Neuropeptides of the human magnocellular hypothalamus

Hypothalamic magnocellular nuclei with their large secretory neurons are unique and phylogenetically conserved brain structures involved in the continual regulation of important homeostatic and autonomous functions in vertebrate species. Both canonical and newly identified neuropeptides have a broad spectrum of physiological activity at the hypothalamic neuronal circuit level located within the supraoptic (SON) and paraventricular (PVN) nuclei. Magnocellular neurons express a variety of receptors for neuropeptides and neurotransmitters and therefore receive numerous excitatory and inhibitory inputs from important subcortical neural areas such as limbic and brainstem populations. These unique cells are also densely innervated by axons from other hypothalamic nuclei. The vast majority of neurochemical maps pertain to animal models, mainly the rodent hypothalamus, however accumulating preliminary anatomical structural studies have revealed the presence and distribution of several neuropeptides in the human magnocellular nuclei. This review presents a novel and comprehensive evidence based evaluation of neuropeptide expression in the human SON and PVN. Collectively this review aims to cast a new, medically oriented light on hypothalamic neuroanatomy and contribute to a better understanding of the mechanisms responsible for neuropeptide-related physiology and the nature of possible neuroendocrinal interactions between local regulatory pathways.

Distribution Patterns of Cocaine- and Amphetamine-Regulated Transcript- and/or Galanin-Containing Neurons and Nerve Fibers Located in the Human Stomach Wall Affected by Tumor

The aim of the study was to investigate the distribution patterns of cocaine- and amphetamine-regulated transcript- (CART-) and galanin-immunoreactive (GAL-IR) neuronal structures in the human stomach wall, focusing on differences observed in regions directly affected by the cancer process, and those from the surgical margin. Samples from the stomach wall were collected from 10 patients (3 women and 7 men, the mean age 67.0 ± 11.9). Next, triple-immunofluorescence staining was used to visualize the changes in the frequency of neurons inside myenteric plexi and intramural fibers containing CART and/or GAL, as well as protein gene product 9.5 (as panneuronal marker). Tumor into the stomach wall caused a decrease in the number of CART-positive (+) nerve fibers in the longitudinal (LML) and circular muscle layers (CML). Notable changes in the dense network of CART+/GAL+ nerve fibers (an increase) were observed in the LML and lamina muscularis mucosae (LMM) within carcinoma-affected areas of the human stomach. Additionally, an elevated number of these nerve fibers from LMM were accompanied by an increase in the number of fibers containing GAL in the vicinity of the neoplastic proliferation. Obtained results suggest that a carcinoma invasion may affect the innervation pattern of the human stomach wall and their function(s).

Short N-terminal galanin fragments are occurring naturally in vivo

The galanin family currently consists of four peptides, namely galanin, galanin-message associated peptide, galanin-like peptide and alarin. Unlike galanin that signals through three different G protein-coupled receptors; GAL₁, GAL₂, and GAL₃, binding at its N-terminal end, the cognate receptors for other members of the galanin family are currently unknown. Research using short N-terminal galanin fragments generated either by enzymatic cleavage or solid-phase synthesis has revealed differences in their receptor binding properties exerting numerous biological effects distinct from galanin(1-29) itself. Our studies on tissue extracts derived from rat small intestine and bovine gut using chromatographic techniques and sensitive galanin(1-16)-specific radioimmunoassay revealed the presence of immunoreactive compounds reacting with antiserum against galanin(1-16) distributed in distinct elution volumes. These results suggested a possible presence of short N-terminal galanin fragments also in vivo. Moreover, employing immunoaffinity chromatography and reverse-phase high performance liquid chromatography (HPLC) followed by mass spectrometry allowed specific enrichment of these immunoreactive compounds from rat tissues and identification of their molecular structure. Indeed, our study revealed presence of several distinct short N-terminal galanin sequences in rat tissue. To prove their receptor binding, four of the identified sequences were synthetized, namely, galanin(1-13), galanin(1-16), galanin(1-20), galanin(6-20), and tested on coronal rat brain sections competing with ¹²⁵I-labeled galanin(1-29). Our autoradiographs confirmed that galanin(1-13), galanin(1-16), and galanin(1-20) comprehensively displaced ¹²⁵I-galanin(1-29) but galanin(6-20) did not. Here we show, for the first time, that short N-terminal galanin fragments occur naturally in rat tissues and that similar or identical galanin sequences can be present also in tissues of other species.

BIOLOGICAL SIGNIFICANCE

This study is first to provide an evidence of the presence of short N-terminal galanin fragments in vivo in a biological system and provides further foundations for the previous studies using synthetized short N-terminal galanin fragments.

Effects of Fluoxetine Administration on Regional Galanin Expression in Obese Zucker Rat Hypothalamus

The aim of the present work was to study the potential involvement of hypothalamic galanin system in the anorectic mechanism of fluoxetine in obese Zucker rats. Male obese Zucker (fa/fa) rats were administered fluoxetine (10 mg/kg; i.p.) daily for two weeks. The control group was given 0.9% NaCl solution. Significant decreases in food intake, final body weight and total body fat were observed after fluoxetine treatment. Although fluoxetine-treated rats showed a decrease in urine elimination, this effect was not enough to compensate decreased water intake, leading to dehydration, as showed by decreased body water content. Chronic fluoxetine administration increased the numbers of galanin positively immunostained neural cells in medial and lateral preoptic areas, lateral hypothalamic area and paraventricular nucleus (rostral and magnocellular regions), without changes in dorsomedial, ventromedial, supraoptic, suprachiasmatic and arcuate nuclei. Taken into account that galanin stimulates appetite, these results could represent rather a compensatory response against reduced food intake than a direct anorectic mechanism. Changes in the magnocellular region of the hypothalamic paraventricular nucleus suggest a role for galanin neural circuits at this level in fluoxetine-induced hydro-osmotic impairment.

Immunolocalization of NOS, VIP, galanin and SP in the small intestine of suckling pigs treated with red kidney bean (Phaseolus vulgaris) lectin

Lectins belong to a family of glycoproteins that can act both beneficially and detrimentally on the morphology of the small intestine. The aim of the study was to determine whether experimental treatment with red kidney bean (Phaseolus vulgaris) lectin influences the chemical code of the small intestine nervous system of suckling pigs. The immunolocalization sites of vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), substance P (SP) and galanin were determined in control and lectin-treated animals. In all segments of the small intestine (duodenum, jejunum, ileum), the subpopulations of VIP-, NOS-, SP- and galanin-immunoreactive (IR) myenteric neurons were unchanged. After lectin stimulation, increased proportions of NOS-IR and decreased numbers of VIP-IR submucous neurons/mucosa innervating nerve fibers were observed in the duodenum, jejunum and ileum. In lectin-treated animals down-regulation of submucous neurons expressing SP and up-regulation of galanin-IR submucous neurons were seen in the duodenum and jejunum (but not in the ileum). The distribution patterns of NOS-IR, galanin-IR and SP-IR nerve fibers supplying the duodenum, jejunum and ileum of the lectin-treated animals showed no substantial differences in relation to control piglets. We conclude that exposure to red kidney bean (P. vulgaris) lectin substantially changes the chemical content of VIP, NOS, SP and galanin in submucous neurons of the small intestine. These results are in line with previous findings outlining the key role(s) of these substances in enteric neuroplasticity processes and may constitute the basis for further functional studies on maturation of the gut.

Effect of gestational diabetes and intrauterine growth restriction on the offspring's circulating galanin at birth

CONTEXT

Experimental studies linked gestational diabetes mellitus (GDM) and intrauterine growth restriction (IUGR) with altered expression of the offspring's hypothalamic galanin mRNA, possibly contributing to the development of obesity and metabolic syndrome in later life. We hypothesized that plasma galanin levels at birth would reflect presumably altered hypothalamic galanin expression and production that cannot be assessed in the human offspring.

OBJECTIVE

Our objective was to investigate whether neonates born to GDM mothers or being IUGR differ from healthy ones in circulating galanin at birth.

DESIGN, PATIENTS, AND METHODS

Twenty-five neonates born to GDM mothers, 25 with IUGR, and 15 healthy neonates (controls) were prospectively studied. Neonatal plasma galanin levels were assayed immediately after birth by using enzyme immunoassay.

RESULTS

Neonatal plasma galanin showed a high variability within each group and did not differ significantly among the three groups of neonates. No correlation between plasma galanin and anthropometric maternal and neonatal data was found. Multiple linear regression confirmed that the neonatal group (infants of diabetic mothers, IUGR, and controls) was not an independent predictor for galanin levels at birth after controlling for possible confounders, i.e. maternal body mass index and weight gain during pregnancy and neonatal body mass index.

CONCLUSIONS

Circulating galanin levels at birth are not affected by GDM and IUGR, providing no evidence for alternations in hypothalamic galanin expression and secretion in humans, as they were previously documented in experimental models. This fact precludes the use of plasma galanin as an early indicator for the development of obesity and metabolic syndrome in this high-risk population.

Selected pathological, immunohistochemical and ultrastructural changes associated with an infection by Diphyllobothrium dendriticum (Nitzsch, 1824) (Cestoda) plerocercoids in Coregonus lavaretus (L.) (Coregonidae)

The pathological changes induced by an infection of Diphyllobothrium dendriticum (Nitzsch, 1824) plerocercoids in powan, Coregonus lavaretus (L.), from Loch Lomond, Scotland, were assessed using immunohistochemical and ultrastructural techniques. In a sample of 26 powan, the occurrence of encysted plerocercoids of D. dendriticum on the outer surface of the stomach was 38.5% (n = 10) with the number of cysts ranging from 4 to 15 and measuring 4.2 +/- 1.0 mm x 3.4 +/- 0.9 mm (mean +/- SD). Histological examination of intestinal samples also revealed plerocercoids (2-21) encapsulated within a proliferation of mesenteric fibrous tissues of the gastric wall and, occasionally, by the gut lamina propria-submucosa and lamina muscularis. In section, cysts were tri-layered and were formed from a series of concentric whorls of fibroblast and collagen fibre-based connective elements. The extent of necrosis within each muscle layer and the serosa of the stomach differed, notably within the latter that was marked by a chronic inflammatory reaction and fibrosis. Within the cyst and around it, a large number of degranulating mast cell/eosinophilic granule cells were seen, in addition to melano-macrophage centres. Immunohistochemical staining of sections of infected stomach revealed a high density of elements, in close proximity to plerocercoids, staining positive for serotonin, bombesin, substance P and galanin. Uninfected material did not present the same levels of activity. Sections through both infected and uninfected tissue were also tested for elements containing vasoactive intestinal peptide, met-enkephalin, calcitonin gene-related peptide, neuropeptide Y and nitric oxide synthase, but these were absent.

Chemical coding of myenteric neurons with different axonal projection patterns in the porcine ileum

The aim of this study was to perform an immunohistochemical characterization of two different myenteric neuron types of the pig displaying opposite axonal projections. These were type I neurons equipped with lamellar dendrites that projected mainly orally, and type VI neurons that displayed typical axonal dendrites and projected anally. Double immunostainings of longitudinal muscle/myenteric plexus wholemounts from ileal segments of four pigs were performed to visualize neurofilaments (NF) in combination with calcitonin gene-related peptide (CGRP), leu-enkephalin (ENK) and substance P (SP), respectively. Triple immunostainings of wholemounts, using antibodies against neuronal nitric oxide synthase (nNOS) and vasoactive intestinal peptide (VIP) as well as against VIP and galanin (GAL), were performed. We found that 78% of type I neurons immunoreacted to ENK, 21% to CGRP and 24% to SP. The NF-positive type I neurons co-reactive for one of the three above markers displayed mostly frayed outlines of both their somal contours and their broadened dendritic endings. By contrast, most of the non-coreactive type I neurons displayed rather sharply outlined somata and dendrites. No type I neuron immunoreacted to nNOS, VIP or GAL and none of the type VI NF-reactive neurons reacted to CGRP, ENK or SP. All type VI neurons investigated displayed immunoreactivity for nNOS, 92% of which were co-reactive for VIP. Co-reactivity for VIP and GAL was found in 69% of type VI neurons, 21% were positive for VIP but negative for GAL, 9% were negative for both GAL and VIP, and 1% were positive for GAL but negative for VIP. We conclude that there are two subpopulations of morphological type I neurons. One of these displays mainly oral projections and could not be further characterized in this study. The other, which may correspond to neurons innervating the longitudinal and circular muscle layers, were partly immunoreactive for ENK, CGRP and/or SP. Type VI neurons are immunoreactive for nNOS frequently co-localized with VIP and, partly, also GAL. These may be inhibitory motor neurons and are different from VIP/GAL-coreactive minineurons described earlier.

Sexually dimorphic immunoreactivity of galanin and colocalization with arginine vasotocin in the chicken brain (Gallus gallus domesticus)

The bed nucleus of the stria terminalis medialis (BSTM) of adult chickens (Gallus gallus domesticus) was previously shown to synthesize arginine vasotocin (AVT) in males only and coincides spatially and temporally with steroid activity regulating male reproductive behavior. Galanin has been shown to be a potent modulator of the behavioral and neuroendocrine responses in the mammalian BSTM and in other sexually dimorphic brain regions. In the present study of adult chickens the morphological relationship of AVT and galanin was examined by immunohistochemical analysis of two limbic structures, the BSTM and the lateral septum (SL). The analysis also included the hypothalamic nuclei supraopticus (SON) and paraventricularis (PVN). In males galanin and AVT were both synthesized in the BSTM, while in females neither galanin nor AVT was present. Furthermore, in the males galanin and AVT were colocalized in the majority of neurons within BSTM and in fibers of the SL. In both sexes galanin neurons in the PVN were scattered between the distinct clusters of AVT neurons and there was no colocalization of galanin and AVT in single PVN neurons. Furthermore, AVT immunoreactivity was significantly higher in the SON than in the PVN in both sexes. In the SON, galanin was colocalized with AVT in significantly more neurons in hens than in males (P </= 0.05%). These results demonstrate that the distributions of galanin and AVT are sexually dimorphic not only in the limbic BSTM but also in the hypothalamic SON. It is tempting to speculate that galanin in the SON is involved in regulation of oviposition as an AVT-dependent female-specific function.

Prenatal exposure to undernutrition and programming of responses to high-fat feeding in the rat

Fetal undernutrition programmes risk of later metabolic disorders. Postnatal factors modify the programmed phenotype. This study aimed to assess the effects of a postnatal high-fat (HF) challenge on body weight gain, adiposity and gene expression following prenatal undernutrition. Pregnant rats were fed either a control diet or a low-protein (LP) diet, targeted at days 0-7 (LPE), days 8-14 (LPM), or days 15-22 (LPL) gestation. At 12 weeks of age offspring were either fed standard laboratory chow diet (4.13 % fat), or a 39.5 % fat diet, for 10 weeks. LP exposure had no effect on weight gain or abdominal fat in males. Females exposed to LP diet in utero exhibited a similar weight gain on HF diet as on the chow diet. Programming of fat deposition was noted in LPE females and males of the LPM and LPL groups (P = 0.019). Hypothalamic expression of galanin mRNA was similar in all groups, but expression of the galanin-2 receptor was modified by LP exposure in female offspring. Hepatic expression of sterol response element binding protein (SREBP-1c) was decreased by LP at both the mRNA (P = 0.008) and protein (P < 0.001) level. HF feeding increased expression of SREBP-1c mRNA three-fold in controls, with little response noted in the LP groups. Interactions of factors such as postnatal diet, age and sex act together with prenatal factors to determine metabolic function and responsiveness at any stage of postnatal life. This study further establishes a role for prenatal nutrition in programming the genes involved in lipid metabolism and appetite regulation.

[Analysis of enteral nervous system in children with drug resistant ulcerative colitis]

INTRODUCTION

pathogenesis of inflammatory bowel diseases has been intensively investigated for many years. The role of enteric nervous system (ENS) and neuroprotective transmitters such as galanine (GAL), vasoactive intestinal peptide (VIP) and pituitary adenosine cyclase activating peptide (PACAP) has been underlined recently. Neuroprotective transmitters play a role in the regulation of intestinal contractions, ion transport in the intestinal epithelium and modulation of the proinflammatory cytokine production, which may result in diminuation of inflammation.

AIM OF THE STUDY

was to investigate activity of ENS in children with drug resistant ulcerative colitis measured by the density of GAL, VIP and/or PACAP containing nervous fibres in mucosal membrane in course of pharmacological treatment and 12 months after colectomy.

MATERIAL AND METHODS

16 children were included in the study. Group I consisted of 7 children with drug resistant ulcerative colitis. Mucosal biopsy specimen was taken twice: colonoscopy before colectomy during (12 months earlier on average) and from resected colon. Group II (reference group) consisted of 9 children with excluded inflammatory bowel diseases based on colonoscopy and biopsy mucosal specimen assessment. Histology and immunochemistry of mucosal samples were analysed.

RESULTS

decreased density of GAL, VIP and/or PACAP containing nervous fibres in colon mucosal membrane of children with ulcerative colitis was found: GAL-IR (3.5 +/- 3.15), VIP-IR (19.7 +/- 2.7), PACAP-IR (6.3+/-2.52) as compared to the reference group: GAL-IR (11.2+/-5.58), VIP-IR (36.1 +/- 16.0) and PACAP-IR (15.7 +/- 9.95). Significant diminuation of the density of GAL, VIP and/or PACAP containing nervous fibres was found in the study.

CONCLUSION

1. The density of VIP, PACAP and GAL containing nerve fibres diminishes in the course of ulcerative colitis, which may be a result of progressive degradation of colon mucosal membrane. 2. The hypothesis that absence of chemotaxis inhibition by low levels of neuroprotective transmitters might be a reason for drug resistance in ulcerative colitis.

Hypothalamic galanin and early state of hyperphagia in obese Zucker rats

Galanin (GAL) stimulates food intake in normal rats when it is injected in different hypothalamic areas involved in feeding such as the paraventricular and ventromedial nuclei and the lateral hypothalamus. At adulthood, the hyperphagic obese Zucker rat is characterized by a general dysregulation of some important neuropeptides involved in the regulation of food intake including GAL. The aim of this study was to measure GAL in different microdissected brain areas in 2- and 4-week-old lean (FA/-) and obese (fa/fa) male Zucker rats in order to know if GAL actively participates in triggering abnormal feeding behavior in obese rats. There was a significant increase (40%-220%) in GAL concentration with age in the arcuate and dorsomedial nuclei and in the above areas except for the lateral hypothalamus. Genotype differences were observed in the arcuate and paraventricular nuclei only. GAL levels were globally lower in obese than in lean rats (-15% to -25%) and the difference was significant at 2 weeks of age in the paraventricular nucleus and at 4 weeks of age in the arcuate nucleus. In agreement with human observations, these data suggest that GAL is not an early player in the development of overeating.

Galanin-like immunoreactivity in the brain of the snake Bothrops jararaca

The distribution of galanin-like immunoreactive perikarya and nerve fibers in the brain of the snake Bothrops jararaca was studied by means of immunohistochemistry using an antiserum against porcine galanin. Immunoreactive neurons were only detected in the infundibular recess nucleus. Immunoreactive fibers were found in the telencephalic, diencephalic and mesencephalic areas such as the dorsal cortex, nucleus accumbens, lamina terminalis, preoptic area, mediodorsal region of the supraoptic nucleus, subfornical organ, nucleus of the paraventricular organ, subcommisural organ and periventricular grey region. The habenula, paraventricular nucleus, infundibular recess nucleus and hypothalamo-hypophyseal tract presented denser innervations. The outer layer of the median eminence displayed numerous fibers located close to the portal system, while scarce fibers were seen in the inner median eminence and neural lobe of the hypophysis. The distribution of labelled neurons in the brain of this snake was more restricted than that described in a turtle. The wide hypothalamic and extrahypothalamic distribution of labelled fibers suggests that galanin peptides may have hypophysiotropic, neuromodulator and neurotransmitter roles in the snake B. jararaca.

Galanin modulates neuronal and synaptic properties in the rat supraoptic nucleus in a use and state dependent manner

The magnocellular neurons of the hypothalamic supraoptic nucleus (SON) synthesize and secrete oxytocin (OXT) and vasopressin (AVP) from their dendrites. These peptides, and several other neurotransmitters, have been shown to modulate afferent glutamatergic neurotransmission in the SON. The neuropeptide, galanin (GAL) is also localized in SON magnocellular neurons and in afferent fibers in the nucleus. We show that GAL dose-dependently reduces evoked excitatory postsynaptic currents (eEPSCs), alters paired pulse ratio and decreases mEPSC frequency, but not amplitude or decay kinetics in both OXT and AVP neurons. GAL therefore modulates excitatory neurotransmission at a likely presynaptic receptor. Neither OXT/AVP, GABA(B) nor cannabinoid antagonists blocked this effect. A GAL2/3 agonist mimicked GAL's action while GAL1 antagonist did not block GAL's effect, suggesting that GAL2/3 receptors mediate the presynaptic effect. In nondehydrated rats GAL causes a small postsynaptic response, as assessed by input resistance measurements. When the rats were water deprived for 2 days the presynaptic response to GAL was unaltered; however, the postsynaptic decrease in input resistance and hyperpolarization was increased, an effect consistent with a previously described increase in GAL1 receptor expression in dehydration. A GAL1 receptor antagonist blocked the postsynaptic effects. Last, when a train of eEPSCs was elicited, GAL was found to inhibit the earlier events in a train but not the latter. This indicates that GAL may modulate a single synaptic event more effectively than trains of synaptic inputs, thereby acting as a high-pass filter.

[Changes in the number of neuroprotective transmitter containing mucosal nerve fibres in children with ulcerative colitis]

INTRODUCTION

Ulcerative colitis and Crohn's disease are two main disease entities that belong to the group of inflammatory bowel diseases (IBD). Chronic inflammatory process concerning intestinal mucosal membrane causes structural and functional changes of intestinal nervous system. This phenomenon is called the plasticity of the nervous system and is due to the ability of nerve cells to adapt to changing environmental conditions. The resulting alterations of intestinal neurons' chemical code are augmentation, inhibition or initiation of the neurotransmitters' synthesis (synthesis "de novo"). The role of neuroprotective transmitters - galanine (GAL), vasoactive intestinal peptide (VIP) and pituitary adenosine cyclase activating peptide (PACAP) seems to be important in the pathogenesis of inflammatory bowel diseases. They are responsible for the regulation of intestinal contraction and modification of ions' transport in the intestinal epithelium. They also diminuate the inflammation by modulation of the proinflammatory chemokines and cytokines production.

THE AIM

of the study was to analyse the changes in the nerve fibres' containing GAL, VIP and/or PACAP, density in the mucosal membrane of children with ulcerative colitis (UC) with different Clinical activity index.

MATERIAL AND METHODS

the study included 33 children hospitalised due to UC with different activity and 9 children in the control group, after exclusion of IBD. All the studied patients underwent colonoscopic examination with colon mucosa biopsies. Histology and immunochemistry of mucosal samples were analysed. Those studies helped to assess the changes in the number of nerve fibres containing analysed transmitter substances in the mucosal membrane of the colon.

RESULTS

the results showed a statistically significant diminuation of nerve fibres containing analysed neurotransmitters number in colon mucosa samples of children with UC. There were no statistically significant changes in number of nerve fibres dependent on the clinical activity index of UC.

CONCLUSIONS

the process of degradation present in UC is accompanied by the important diminuation on neurotransmitter containing fibres number. However, their density is not dependent of the clinical activity of the disease.

Neurochemical properties of the middle cervical ganglion in the sheep

The neurochemical properties of the ovine middle cervical ganglion (MCG) were studied using antibodies raised against tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DbetaH), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and galanin (GAL). Double-labelling immunocytochemistry revealed that the vast majority (95.5 +/- 0.8%) of postganglionic sympathetic MCG neurons expressed simultaneously both catecholamine-synthesizing enzymes (neurons were TH/DbetaH-positive). A large population of noradrenergic neurons exhibited immunoreactivity (IR) to NPY (62.2 +/- 2.2%), but single NPY-positive perikarya-lacking noradrenergic markers were also observed (2.0 +/- 0.3%). None of the examined MCG neuronal somata contained SP, CGRP, GAL or VIP. A moderate number of noradrenergic nerve fibres located amongst neuronal cell bodies was also found. In small number of these terminals the presence of NPYor GAL (but not CGRP or VIP) was detected. The ovine MCG was numerously innervated with SP-immunoreactive nerve fibres which sometimes formed basket-like formations around postganglionic neurons. The MCG exhibited a sparse CGRP-immunoreactive innervation and lacked VIP-positive nerve terminals. In many aspects the chemical coding of MCG postganglionic neurons and nerve terminals resembles that found in other mammalian cervico-thoracic paravertebral ganglia, but some important species-dependent differences exist. The functional implications of these differences remain to be elucidated.

Morphological evidence of sensory neurons in the root of the rat tongue

In our previous studies, a large number of substance P (SP)-immunoreactive (IR) nerve fibers were detected in the rat tongue and their number increased after inflammation, suggesting that these fibers might be involved in the axon reflex. Therefore, in this study, we have examined the different neuropeptide-containing nerve elements by light, electron, and confocal laser microscopy. SP, vasoactive intestinal polypeptide (VIP), and neuropeptide Y (NPY) IR varicose fibers were numerous compared with other ones. Small groups of ganglia with perikarya IR for SP, VIP, NPY, galanin, and somatostatin were observed. The SP-IR nerve cell bodies were mainly located in the tunica propria just below the epithelial lining. Double-labeling immunohistochemistry showed that the intrinsic SP-IR neurons did not colocalize VIP. The SP containing nerve terminals were observed in and below the epithelium as well as in very close contact to or making real synapses with other neurons in the intralingual ganglion. Our data confirmed the possibility of intrinsic sensory neurons, which might be the afferent branch of the intralingual reflex arch, while the VIP- and NPY-IR neurons located in the salivary glands, around the blood vessels, and in the muscle layer might constitute the efferent site of this reflex.

Different forms of obesity as a function of diet composition

OBJECTIVE

To characterize the phenotype of obesity on a high-carbohydrate diet (HCD) as compared to a high-fat diet (HFD) or moderate-fat diet (MFD).

METHODS AND PROCEDURES

In four experiments, adult Sprague-Dawley rats (275-300 g) were maintained for several weeks on a: (1) HFD with 50% fat; (2) balanced MFD with 25% fat; or (3) HCD with 10% fat/65% carbohydrate. Then, based on the amount of body fat accumulated in four dissected fat pads, the animals were subgrouped as lean (lowest tertile) or obese (highest tertile) and characterized with multiple measures.

RESULTS

The obese rats of these diet groups, with 70-80% greater body fat than the lean animals, exhibited elevated levels of leptin and insulin and increased activity of lipoprotein lipase in adipose tissue (aLPL), with no change in muscle LPL. Characteristics common to the obese rats on the HFD or MFD, but not seen on the HCD, were hyperphagia, elevated circulating levels of triglycerides (TG), nonesterified fatty acids (NEFA) and glucose, and a significant increase in beta-hydroxyacyl-CoA dehydrogenase (HADH) activity in muscle, reflecting its greater capacity to metabolize fat. This was accompanied by a significant increase in expression of the peptide, galanin (GAL), in the paraventricular nucleus (PVN), as measured by in situ hybridization and real-time quantitative PCR, and also in GAL peptide immunoreactivity. These measures of GAL were consistently, positively correlated with circulating TG levels and also with HADH activity in muscle. In contrast to these fat-associated changes, rats that became obese on an HCD maintained normal caloric intake and levels of TG, NEFA, and glucose. They also showed no change in PVN GAL mRNA or peptide. Instead, they exhibited a significant reduction in HADH activity compared to the lean animals, along with increased activity of phosphofructokinase in muscle, a key enzyme in glycolysis.

CONCLUSION

Specific characteristics of obesity, including expression of hypothalamic peptides, are dependent upon diet composition. Whereas obesity on an HFD is associated with hyperphagia and elevated lipids, fat metabolism in muscle, and fat-stimulated peptides such as GAL, obesity on an HCD with a similar increase in body fat shows none of these characteristics and instead exhibits a metabolic pattern in muscle that favors carbohydrate over fat oxidation. These results suggest the existence of multiple forms of obesity with different underlying mechanisms that are diet dependent.

Circulating acylated and total ghrelin and galanin in children with insulin-treated type 1 diabetes: relationship to insulin therapy, metabolic control and pubertal development

OBJECTIVE

To study the circulating levels of two gut-derived peptides in children with type 1 (insulin-dependent) diabetes mellitus (IDDM).

RESEARCH DESIGN AND METHODS

Plasma levels of ghrelin, both total ghrelin (TG) and the acylated form (AG), and galanin and their relationships with insulin dosage, metabolic control, IGFBP-1, body mass and pubertal development were evaluated in 91 children, aged 11.1 +/- 2.7 years, affected by IDDM and treated with insulin. Ninety-one healthy children were selected as controls.

RESULTS

Body mass index (BMI)-adjusted levels of both forms of ghrelin were reduced in IDDM compared with healthy subjects, with greater values in prepubertal than pubertal IDDM subjects. A negative association was found between AG and fasting insulin serum levels and insulin resistance [measured by using the homeostasis model assessment of insulin resistance (HOMA IR)] among the healthy children. IDDM children showed a negative association of their plasma ghrelin (both acylated and total) with daily insulin dosage, and the three adiposity indices (BMI, skinfold thickness and percentage fat mass). IGFBP-1 levels were higher among the IDDM children without any association with ghrelin serum values. BMI-adjusted plasma levels of galanin were higher among IDDM compared to healthy subjects, irrespective of sex or pubertal development. Greater values for galanin were found among pubertal than prepubertal subjects in both groups without any significant differences between the genders. A positive association was found between galanin and BMI in both groups and between galanin and haemoglobin A1c (HbA1c) among the IDDM children. No relationship existed between either galanin and fasting serum insulin among the healthy subjects or galanin and both insulin dosage or duration of treatment among the IDDM subjects.

CONCLUSIONS

The associations found between both ghrelin and galanin with adiposity indices could be considered as an indirect signal of involvement of the two peptides in the development of the nutritional status of the IDDM adolescents. The reduction in both forms of ghrelin could be involved in the development of the body mass increase of IDDM subjects with opposite effects, either influencing insulin sensitivity or exerting a compensatory restraint of feeding.

Fasting-induced changes of neuropeptide immunoreactivity in the lateral septum of male rats

The objective of the present study was to determine the rostrocaudal distribution and the effect of reduced food intake (60% of the average daily food intake for 1-4 weeks) on the amount of leucine-enkephalin (Leu-enk), neuropeptide Y (NPY) and galanin (Gal) in the lateral septum of male rat brain. Using pre-embedding immunocytochemistry combined with densitometry on 60 microm serial vibratome sections we found that in control animals Leu-enk-immunoreactive elements showed an increasing density from rostral towards the medial part of the septum, then a gradual decrease towards the caudal direction. The distribution of NPY proved to be rather even along the examined sequence of sections with two smaller peaks roughly at the 1/3 and 2/3 of the rostrocaudal axis. Gal showed similar distribution but the peaks were shifted to more caudal direction. We also found that Leu-enk forms the most dense plexus followed by a moderate amount of NPY-positive axonal meshwork. Gal was present in the lowest amount along the lateral septal nuclei. The effect of reduced food intake was marked and differential in the case of the three examined peptides. During the first 2 weeks of reduced food intake NPY-immunoreactivity was upregulated as compared to the control, then it was reduced close to the control value by the 4th week. The changes in Gal immunoreactivity showed similar pattern. The average relative density of Leu-enk-immunoreactive elements immediately decreased as a result of reduced food intake for 1 week and it gradually decreased by the end of the 4th week. These results indicate that reduced food intake affects the expression of NPY, Gal and Leu-enk not only in the relevant hypothalamic neuroendocrine centres, but also in the lateral septal area.

Increase in sensory neuropeptides surrounding the Achilles tendon in rats with adjuvant arthritis

The Achilles tendon in rats with adjuvant arthritis was analyzed by radioimmunoassay (RIA) and semi-quantitative immunohistochemistry for the occurrence of two sensory neuropeptides, substance P (SP) and calcitonin gene related peptide (CGRP), and a sensory modulating peptide, galanin (GAL). The tissue concentration of SP and CGRP in the Achilles tendon and its envelope, i.e. the paratenon and bony insertion, as assessed by RIA was increased by 22% and 71%, respectively, compared to normal controls, whereas the level of GAL was unchanged. Semi-quantitative immunohistochemistry applied to different regions of the tendon in arthritic rats disclosed an increased occurrence of SP and CGRP positive nerve fibers in the paratenon and bone tendinous junction, whereas GAL fibers were only increased at the bone tendinous junction. Notably, neither neuropeptides nor inflammatory cells were seen in the tendon proper. The increased occurrence of SP and CGRP in the tendon envelope presumably reflects inflammatory actions, whereas that of GAL implies an endogenous anti-inflammatory response. The observed SP and CGRP upregulation in the paratenon and bony insertion suggests a pathophysiological role in paratenonitis and enthesitis often seen in patients with rheumatoid arthritis. Presumably Achillodynia originates in the tendon envelope rather than the tendon proper. The observations could be used to define new pharmacological targets for mitigating symptoms from tendons in rheumatoid arthritis and possibly also in other disorders. Whether a neuronal pathogenic mechanism underlies tendon overuse disorders in non-arthritic tendinopathies and the development of degeneration, i.e. tendinosis, remains to be studied.

Morphological basis of sensory neuropathy and neuroimmunomodulation in minor salivary glands of patients with Sjögren's syndrome

OBJECTIVE

A predominance of sensory neuropathy was earlier described in Sjögren's syndrome (SS), which might precede the presence of sicca symptoms. The mechanism of sensory neuropathy in SS is unknown. Therefore, the aim of this study was to determine the quantitative changes of the different neuropeptide containing nerve terminals and the immunocompetent cells in labial salivary glands of primary SS.

DESIGN

Immunohisto- and immunocytochemical methods were used for the detection of immunoreactive (IR) elements and the data were compared with the healthy controls.

RESULTS

All of the investigated IR nerve fibres were found in different quantity and localisation in both of control and SS glands. The density of them was changed variously in SS. The number of the substance P (SP), neuropeptide Y (NPY) (P < 0.05), galanin (GAL) IR nerve terminals was decreased, however, the number of vasoactive intestinal polypeptide (VIP) and tyrosine beta-hydroxylase (TH) IR nerve fibres (P < 0.05) was increased compared to the control. There were no IR immunocompetent cells in the control materials, however, a large number of them showed IR for SP (46.2%) and NPY (34.4%) in the SS. The IR was demonstrated mainly in the mast cells, plasma cells and some of the lymphocytes.

CONCLUSIONS

These neuropeptides might have a role in the sensory neuropathy; they might activate nociceptive and sympathetic pathways. Some neuropeptides (SP, NPY) are endogenous in the immune system and produced in certain conditions, e.g. inflammation and chronic autoimmune disorders such as SS, so they might participate in the neuroimmunomodulation and contribute to the atrophy, apoptosis and necrosis.

Immunocytochemical properties of stellate ganglion neurons during early postnatal development

Neurotransmitter features in sympathetic neurons are subject to change during development. To better understand the neuroplasticity of sympathetic neurons during early postnatal ontogenesis, this study was set up to immunocytochemically investigate the development of the catecholaminergic, cholinergic, and peptidergic phenotypes in the stellate ganglion of mice and rats. The present study was performed on Wistar rats and Swiss mice of different ages (newborn, 10-day-old, 20-day-old, 30-day-old, and 60-day-old). To this end, double labeling for tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), vasoactive intestinal (poly)peptide (VIP), neuropeptide Y (NPY), galanin (GAL), and somatostatin (SOM) was applied. The results obtained indicate that the majority of the neurons in the stellate ganglion of both species were TH-positive from birth onward and that a large part of these neurons also contained NPY. The percentage of neurons containing TH and NPY invariably increased with age up to 60 days postnatally. A smaller portion of the stellate ganglion neurons contained other types of neuropeptides and showed a distinct chronological pattern. The proportion of VIP- and ChAT-positive neurons was maximal in 10-day-old animals and then decreased up to 60 days of age, whereas the number of SOM-positive cells in rats significantly decreased from birth onward. In newborn rats, VIP-, ChAT- and SOM-positive neurons were largely TH-positive, while their proportions decreased in 10-day-old and older rats. Accordingly, the largest part of VIP-positive neurons also expressed SOM immunoreactivity at birth, after which the number of neurons containing both peptides diminished. The VIP- and SOM-positive cells did not contain NPY in any of the age groups studied. In rats up to 10 days of life, GAL-immunoreactive (-IR) neurons were scarce, after which their number increased to reach a maximal value in 30-day-old animals and then declined again. The SOM-reactive cells had the smallest size in all rats, while the largest neurons were those containing ChAT. In the mouse stellate ganglion, VIP- and ChAT-IR neurons were larger in comparison to NPY- and TH-IR cells. Our study further revealed some species differences: compared to mice the proportion of neurons containing TH and NPY was higher in rats at all ages under study. Furthermore, no GAL-immunostained neurons were found in mice and the number of SOM-positive cells in mice was limited compared to that observed in rats. In conclusion, the development of neurotransmitter composition is complete in rats and mice by their second month of life. At this age, the percentages of immunopositive cells have become similar to those reported in adult animals.

Galanin- but not galanin-like peptide-containing axon terminals innervate hypophysiotropic TRH-synthesizing neurons in the hypothalamic paraventricular nucleus

Galanin and galanin-like peptide (GALP) are both orexigenic peptides involved in the regulation of food intake and energy metabolism. To determine whether these peptides may directly influence the hypophysiotropic thyrotropin-releasing hormone (TRH)-synthesizing neurons, double-labeling immunocytochemistry was performed at light and electron microscopic levels using antisera against proTRH, galanin and GALP. Galanin-IR axons densely innervated all of the major parvocellular subdivisions of the PVN where proTRH neurons were identified. The periventricular and anterior parvocellular subdivisions exhibited a prominent network of galaninergic nerve fibers, while the density of fibers was less intense in the medial parvocellular subdivision. Galanin-immunoreactive (IR) axon varicosities were juxtaposed to the majority of TRH-synthesizing neurons in the anterior, medial and periventricular subdivisions of the PVN. Ultrastucturally, galanin-IR nerve terminals established symmetric type synapses with the perikarya of proTRH-IR neurons, suggesting an inhibitory nature of these contacts. In contrast, GALP immunoreactive fibers and nerve terminals concentrated primarily in the anterior parvocellular subdivision of the PVN and were found in association with only few proTRH-IR neurons in the periventricular and medial parvocellular subdivisions. In conclusion, the dense innervation of TRH neurons in all subdivisions of the PVN by galanin-IR axons indicates that galanin may be involved in the central regulation of the hypothalamic-pituitary-thyroid axis. In contrast, the relative paucity of GALP-containing axons in juxtapsoition to TRH neurons in the medial and periventricular parvocellular subdivisions of the PVN, the origin of hypophysiotropic TRH neurons, makes it unlikely that GALP similarly exerts direct regulatory effects on hypophysiotropic TRH neurons.

Neuromodulation of experimental Shigella infection reduces damage to the gut mucosa

Bacillary dysentery arises when Shigella invades the colonic and rectal mucosae of the human gut and elicits a strong inflammatory response, which may lead to life-threatening complications. Hence, downregulation of the host inflammatory response is an appealing therapeutical alternative. The gastrointestinal tract is densely innervated, and nerve endings are often found in the vicinity of leukocytes. We have assessed the impact of experimental Shigella infection on levels of neuropeptides in the intestinal mucosa of rabbits. Ligated small intestinal loops were created in rabbits, and either live, pathogenic Shigella flexneri, a nonpathogenic mutant of Shigella, or NaCl was injected into the loops. Infection was allowed to proceed for 8 or 16 h, after which the rabbits were sacrificed and intestinal biopsies collected. Tissue destruction, fluid secretion and degree of bacterial invasion were monitored. Intestinal biopsies were homogenized, and levels of the neuropeptides calcitonin gene-related peptide, substance P, peptide YY (PYY), vasoactive intestinal peptide, somatostatin, galanin, motilin and neurotensin were measured by radioimmunoassay. Loops exposed to invasive Shigella had 5.7 times lower levels of PYY (P = 0.0095) than loops exposed to NaCl, after 16 h of infection. The levels of the other neuropeptides tested were unchanged. Inhibition of nicotinic cholinergic neurotransmission partly protected the intestinal mucosa from destruction elicited by invasive Shigella. These findings indicate that a tissue-invasive bacterium such as Shigella, which is strictly localized to the intestinal mucosa, activates intramural nerve reflexes that presumably involve a nicotinic synapse as well as the neuropeptide PYY.

Galanin in adjuvant arthritis in the rat

OBJECTIVE

To study the concentration changes of galanin in the ankles and spinal cord and to detect the distribution of galanin in different tissues in arthritic rats.

METHODS

Adjuvant arthritis was induced by intradermal injection of Mycobacterium butyricum in Freund's incomplete adjuvant at the base of the tail. The concentrations of galanin were measured by radioimmunoassay (RIA) and the distributions of galanin were detected by immunoelectron microscopy (iEM).

RESULTS

Measurements were taken on Day 28 after injection. RIA results showed that the concentration of galanin was significantly lower in the ankles and spinal cords of rats with adjuvant arthritis compared to controls. Our iEM results showed a heterogeneous distribution of galanin labelling in different cells and tissue compartments. In arthritic rats, we observed decreased galanin labelling in the sciatic nerve and in macrophage-like cells in the synovial membrane and increased labelling in monocyte lineage cells, polymorphonucleated lineage cells in the bone marrow, fibroblasts in the periosteum, osteoclasts and osteocytes, and lower labelling in osteoblasts compared to controls.

CONCLUSION

Galanin is involved in the response to inflammation in adjuvant arthritis and might play a role in the regulation of inflammation and nociception. These findings are in accordance with a biological role of galanin in the development of inflammatory arthritis.

Galanin receptor subtype GalR2 mediates apoptosis in SH-SY5Y neuroblastoma cells

Recently we have shown that galanin binding significantly correlates with survival in neuroblastoma patients, indicating a possible modulatory role of galanin receptors in neuroblastic tumor biology. However, the molecular mechanisms beyond this correlation have not been elucidated. Here, the cellular effects on activation of specific galanin receptor subtypes in human SH-SY5Y neuroblastoma cells were analyzed using a tetracycline-controlled expression system. Pharmacological studies confirmed the inducible expression of high affinity binding sites for galanin in SH-SY5Y cells transfected with the galanin receptors GalR1 (SY5Y/GalR1) and GalR2 (SY5Y/GalR2). Microphysiometry revealed that both receptor subtypes were able to mediate an intracellular signal upon galanin application. Interestingly, induction of receptor expression and treatment with 100 nm galanin resulted in a dramatic decrease in cell viability in SY5Y/GalR2 cells (93 +/- 3%) compared with a less pronounced effect in SY5Y/GalR1 cells (19 +/- 10%). The antiproliferative potency of galanin was 100-fold higher in SY5Y/GalR2 (50% effective concentration, 1.1 nm) than in SY5Y/GalR1 cells (50% effective concentration, 190 nm). Furthermore, activation of receptor expression and exposure to galanin resulted in apparent morphological changes indicative of apoptosis in SY5Y/GalR2 cells only. Induction of cell death by the apoptotic process was confirmed by poly-(ADP-ribose)-polymerase cleavage, caspase-3 activation, and the typical laddering of DNA. This study indicates that a high level of GalR2 expression is able to inhibit cell proliferation and induce apoptosis in neuroblastoma cells and therefore identifies GalR2 as a possible target for pharmacological intervention in neuroblastoma.

Distribution of calcitonin gene-related peptide (CGRP), substance P (SP) and galanin (GAL) immunoreactive nerve fibers in the seminal vesicle and prostate of the male sheep

Double immunohistochemistry was used to determine the occurrence and distribution pattern of nerve fibres immunoreactive to calcitonin gene-related peptide (CGRP), substance P (SP) and galanin (GAL) in seminal vesicles and prostate of the male sheep. Numerous CGRP- and SP-immunoreactive (IR) nerve fibres were found in the mucosal layer and smooth musculature of the seminal vesicles and prostate. In both glands nerve terminals immunoreactive to CGRP were more numerous than SP-IR ones. The majority of CGRP-IR nerve fibers showed colocalization of this peptide and SP. In both layers of the seminal vesicle and prostate, rare nerve terminals immunoreactive to GAL were also found. Immunoreactivity to SP was also found in all GAL-IR nerve fibers. The presence of numerous CGRP- and SP-IR nerve fibers in the seminal vesicle and prostate of the male sheep suggests that these neuropeptides may be involved in the sensory transmission and/or control of smooth muscle contractility. On the other hand, a relatively low number of GAL-IR nerve fibers of the seminal vesicle and prostate suggest that this peptide may act as an anti-nociceptive agent. It cannot be excluded that, in the seminal vesicle, GAL may also be involved in the control of the smooth muscle fiber activity. The possible role of CGRP, SP and GAL in the regulation of functions of the accessory sexual glands needs to be determined in further physiological studies.

Expression of galanin and galanin receptor-1 in normal bone and during fracture repair in the rat

The neuropeptide galanin (GAL) has recognized physiological actions in the nervous system and other tissues, but there is no documented evidence of GAL influencing normal or pathological bone metabolism. GAL expression, however, is upregulated in central and peripheral nerves following axotomy and is known to influence neural regeneration. Thus, severance of skeletal-associated nerves during fracture could similarly increase local GAL concentrations and thereby influence fracture healing. The initial aim of this study was therefore to identify the presence of GAL in normal bone and/or fracture callus by assessing the concentration and cellular localization of GAL in intact and/or fractured rat rib, using radioimmunoassay and immunohistochemistry, respectively. Groups of Sprague-Dawley rats (13 weeks old) had their left sixth ribs surgically fractured or underwent sham surgery and then calluses and nonfractured rib samples were analyzed at 1 and 2 weeks postsurgery (n = 5-6 per group). Low (basal) concentrations of GAL were detected in control ribs, whereas at 1 and 2 weeks postfracture, callus samples contained markedly increased levels of peptide ( approximately 32- and 18-fold increase, respectively, relative to controls; P < 0.01), revealing a strong upregulation during bone healing. Plasma GAL concentrations were also increased at 2 weeks postfracture (P < 0.005). In normal (nonfractured) rib, minimal levels of GAL-like immunoreactivity (LI) were present in cortical bone, periosteum, endosteum, and surrounding skeletal muscle. In costal cartilage plates, intense GAL-LI was present in all chondrocytes of the hypertrophic zone and in a population of chondrocytes in the reserve zone. GAL-LI was not present, however, in chondrocytes in the proliferative zone of costal cartilage or skeletal muscle fibers. In fracture callus, levels of GAL-LI were moderate to intense in osteoprogenitor cells and osteoblasts, in some chondrocytes, and in cartilaginous, osseous, and periosteal matrices. Subsequent studies revealed the presence of galanin receptor-1-like immunoreactivity (GALR1-LI) in most cell types shown to contain GAL-LI, although the distribution of GALR1-LI was more extensive in reserve zone chondrocytes than that of GAL-LI; and GALR1-LI also appeared in late proliferative zone chondrocytes of costal cartilage. In summary, GAL concentrations were significantly increased in fracture callus and plasma of rats that underwent rib fracture. In addition, GAL- and GALR1-LI was also detected in specific cells and structures within costal cartilage, bone, and fracture callus. These results strongly implicate GAL in aspects of cartilage growth plate physiology and fracture repair, possibly acting in an autocrine/paracrine fashion via GALR1.

Immunohistochemical localization of substance P, calcitonin gene-related peptide, galanin and calcium-binding proteins in trigeminal ganglia of goat (Capra hircus)

The objectives of this study was to provide a quantitative analysis of calcium-binding proteins, calbindin (CB), parvalbumin (PA), substance P (SP), calcitonin gene-related peptide (CGRP) and galanin (GAL), in trigeminal ganglia of goats, to establish whether they exhibit coexistence relationships between each other, and to examine possible colocalization with SP, CGRP and GAL, which have been well characterized according to their distributions in an abundance of large and/or small neurones. CB (12.78%), PA (31.91%), SP (24.63%), CGRP (44.44%) and GAL (3.29%) immunoreactive (IR) cells were observed. About 38.37, 8.7 and 0.73% of CGRP-IR neurones in the trigeminal ganglion were also immunoreacted with SP, GAL and CB, respectively. Almost all SP-IR cells are labelled with CGRP (approximately 92.52%), whereas only 16.02 and 0.44% of SP-IR neurones colocalized with GAL and CB. Approximately 4.65 and 1.10% of the CB-IR cells were found to contain CGRP and SP immunoreactivity, respectively. Conversely, no CB-IR cell exhibited GAL immunoreactivity. In addition, all the GAL-IR cells showed CGRP and SP immunoreactivity. The number of CB-, PA-, SP-, CGRP- and GAL-IR neurones in goat trigeminal ganglion are abundant than that of other animals. These results elucidate that the goat differs from other mammalian species in the distribution and localization of neurochemical substances in trigeminal ganglia, and suggest that this difference may be relevant to the morphological characteristics of cerebral vasculatures such as epidural rete mirabile of goat.

Galanin-immunoreactive nerve fibers in the periodontal ligament during experimental tooth movement

Neuropeptides have been suggested to play a role in pain transmission during orthodontic tooth movement. We examined this hypothesis by examining the effect of orthodontic tooth movement on the expression of galanin (GAL)-immunoreactive (ir) nerve fibers in the periodontal ligament (PDL) of one mesial root (MR) and two distal roots (DRs) of the rat maxillary first molar. In control rats, GAL-ir fibers were very rare in the PDL. One day after the insertion of the elastic band, the number of GAL-ir fibers increased, becoming most numerous at 3 days. From 5 to 28 days, GAL-ir fibers tended to decrease. Electron microscopic observation showed that all of the GAL-ir fibers were unmyelinated. These findings suggest that GAL-containing nerve fibers in the PDL may play an important role in the response of the tissue to experimental tooth movement.

Topography and neurochemistry of the enteric ganglia in the proventriculus of the duck (Anas platyrhynchos)

The topographical distribution of the enteric ganglia has been investigated in the proventriculus of the duck using protein gene product 9.5 (PGP 9.5) immunohistochemistry. Myenteric ganglia were usually located between the outer longitudinal and the inner circular muscle layer. Submucous ganglia were sparsely distributed and seemed to be substituted by ganglia located in the tunica mucosa. The neurochemical profile of proventricular ganglion cells was also investigated using nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-histochemistry and pituitary adenylate cyclase activating peptide (PACAP)/galanin (Gal) double-labelling immunohistochemistry. The majority of mucosal ganglion cells were shown to contain the NADPH-d enzyme and both the investigated peptides. These findings provide evidence for the presence of a mucosal ganglionated plexus in the glandular stomach of birds. Moreover, the neurochemical characteristics of this plexus suggest that it plays an important role in regulating several mucosal functions and, in particular, the production and the composition of the gastric juice.

Intrinsic innervation in the tracheal smooth muscle of the large flying fox (Pteropus vampyrus): an immunohistochemical study

Structure and innervation of the trachea of the large flying fox (Pteropus vampyrus) were examined by mean hematoxylin-eosin staining and immunohistochemical methods. The tracheal rings were predominantly comprised of bone with a small amount of hyaline cartilage. Bone contained bone marrow and hyaline cartilage attached at the ends of the tracheal rings. The tracheal rings in the anterior third of the trachea were connected at each end with connective tissue to almost form a ring. A narrow membranous wall comprising a single layer of smooth muscle was present in the middle third, while inner and outer layers of smooth muscle were present in the posterior third. Protein gene product 9.5 (PGP 9.5)-, nitric oxide synthase (NOS)-, galanin- and vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers were present in the epithelium, lamina propria, smooth muscle layer and tunica adventitia. In the tunica adventitia, many PGP 9.5- and NOS-immunoreactive neurons were found singly or in small ganglia, while some VIP- and galanin-immunoreactive neurons were observed. A few PGP 9.5- and NOS-immunoreactive neurons were found in the submucosal layer. These results suggest that the trachea of the large flying fox has a rigid structure of tracheal rings and that the posterior two-thirds of the trachea probably contract via the actions of smooth muscles innervated with peptidergic or nitrenergic neurons that are located in tracheal ganglia, whereas the anterior third is non-mobile.

Uterus-innervating neurones in porcine inferior mesenteric ganglion: an immunohistochemical characteristic

The presence of tyrosine hydroxylase, neuropeptide Y, vasoactive intestinal polypeptide, galanin, Met-enkephalin-Arg-Gly-Leu, substance P and calcitonin gene-related peptide was studied with immunohistochemistry in uterus-innervating neurones found in the inferior mesenteric ganglia after fluorescent tracer (Fast Blue) injection into different regions of the porcine uterus (uterine cervix, paracervical, middle and paraoviductal part of the uterine horn). Virtually all Fast Blue-positive neurones found in the inferior mesenteric ganglia after tracer injection into all studied parts of the uterus contained tyrosine hydroxylase and ca. 45% of them contained neuropeptide Y. Single galanin-positive/Fast Blue-positive cells were found in the ganglia only after tracer injections into uterine cervix. No other studied substances were found in the Fast-Blue positive neurones of the inferior mesenteric ganglia.

Immunohistochemical study of the otic ganglion in the pig

The presence of choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), substance P (SP) and calcitonin gene-related peptide (CGRP) was studied in neurons and nerve fibers of the porcine otic ganglion. ChAT-positive neurons were very numerous while VAChT-positive nerve cells were moderate in number. The number of neurons containing NPY and VIP was lower and those containing SOM, GAL, SP or CGRP were observed as scarce, or single nerve cells. The above mentioned substances (except SOM) were present in nerve fibers of the ganglion. ChAT- and VAChT-positive nerve fibers were numerous, while the number of nerve terminals containing NPY, VIP and SP was lower. GAL- and CGRP-positive nerve fibers were scarce.

Effect of metabolic disorders accompanying gastroenteritis on the pancreatic exocrine function in piglets. C. Histopathological and immunohistochemical changes in the pancreas of piglets with gastroenteritis

The study was performed on 20 piglets of both sexes. The control group consisted of 10 healthy piglets, the experimental, group included 10 piglets with symptoms of gastroenteritis. All the animals were subjected to euthanasia at the age of 21 or 35 days (weaning), or 7 days after weaning, and immunohistochemical and histopathological examinations were performed on all of them. Immunohistochemical examinations of the experimental piglets included additional tests made on five piglets with gastroenteritis, characterized by poor general condition. Histopathological examinations of the pancreas revealed retrogressive changes, which might result from hemodynamic disorders. Changes in the localization of SOM and VIP found in the pancreas suggested inhibition of pancreatic enzyme synthesis in piglets with diarrhea. The co-localization of GAL and dopamine beta-hydroxylase (D beta H--a key enzyme of the noradrenaline synthesis pathway) in perivascular nerve fibers could lead to considerable vasospasms in the pancreas, resulting in deeper hypoxia of the organ. Immunohistochemical and histopathological examinations confirmed the results of biochemical analyses, indicating failure of the pancreatic exocrine function in piglets with gastroenteritis.

Neuronal plasticity in relation to nociception and healing of rat achilles tendon

Nerve regeneration and the occurrence of three neuropeptides; i.e. substance P (SP), calcitonin gene related peptide (CGRP) and galanin (GAL), were studied during healing of tendon rupture in the rat by semi-quantitative immunohistochemistry. The neuronal findings were related to nociception as assessed by hindpaw withdrawal latencies at thermal and mechanical tests. Experimental rupture of rat Achilles tendon--normally devoid of nerves--elicited extensive nerve ingrowth into the rupture site in the early phase of healing followed by almost complete fiber disappearance (weeks 12-16). The ingrowth of SP and CGRP positive fibers, seen already at weeks 1-2, was associated with increased nociception. Subsequently, the occurrence of GAL positive fibers at weeks 4-6 was associated with decreased nociception. An even stronger relationship to nociception during healing was observed when the rate of change in neuropeptide expression instead of the expression in absolute terms was considered, according to the "cascade" formula of SP(')+CGRP(')-GAL(').It may prove that the observed temporal occurrence of different neuropeptides reflects a role of the peripheral nervous system in regulating synchronously nociception and healing.

Sensitivity of galanin- and melanin-concentrating hormone-containing neurones to nutritional status: an immunohistochemical study in the ovariectomized ewe

The sensitivities of galanin and melanin-concentrating hormone (MCH) neuronal systems to nutrition are poorly understood in sheep compared to rodents. The aim of this study was to describe the changes in the numbers of galanin and MCH neurones in ovariectomized ewes submitted to different nutritional levels. In the first experiment, ewes were fed ad libitum or food deprived for 24 h. In the second experiment, two groups of ewes were fed at maintenance level (group 100) or undernourished (group 40) for 167 days, after which one-half of each group was killed or refed ad libitum (group 100R and 40R) for 4 days. The MCH neuronal population located in the lateral hypothalamic area was not affected by these nutritional changes. Long-term undernutrition enhanced the number of galanin neurones located in the infundibular nucleus and the dorsal hypothalamic area (DHA), refeeding resulted in an increase of neurones in the DHA and preoptic area, but short-term starvation had no effect on any galanin subpopulations. Our data suggest that the sensitivity of MCH neuronal populations to nutrition in sheep differs from that of rodents. Various populations of galanin-containing neurones differ in sensitivity in ewes subjected to long undernutrition and refeeding but not to short starvation.

Localization of the neuropeptide galanin in nerve fibers and epithelial keratinocytes of the rat molar gingiva

Knowledge of the histochemical substrates of cellular and neurovascular connections in the gingiva is essential in order to understand the initial mechanisms of inflammation in the periodontium. Since the localization of the neuroendocrine peptide galanin in the gingiva is still unclear, we used immunohistochemical, in situ hybridization and immunoblot techniques to assess the localization of galanin in the gingiva of rat molars. Galanin-immunoreactive nerve fibers were located around blood vessels in the lamina propria, beneath the epithelium, in the epithelial-proprial junction and in the basal layer of the epithelium. Galanin was highly expressed in the suprabasal keratinocytes of the gingival epithelium. The localization of galanin in gingival nerve fibers and the expression of galanin in keratinocytes of the gingival epithelium indicate that galanin may be a possible regulator of different cellular functions in the gingiva.

Ventrolateral preoptic nucleus contains sleep-active, galaninergic neurons in multiple mammalian species

The ventrolateral preoptic nucleus (VLPO) is a group of sleep-active neurons that has been identified in the hypothalamus of rats and is thought to inhibit the major ascending monoaminergic arousal systems during sleep; lesions of the VLPO cause insomnia. Identification of the VLPO in other species has been complicated by the lack of a marker for this cell population, other than the expression of Fos during sleep. We now report that a high percentage of the sleep-active (Fos-expressing) VLPO neurons express mRNA for the inhibitory neuropeptide, galanin, in nocturnal rodents (mice and rats), diurnal rodents (degus), and cats. A homologous (i.e. galanin mRNA-containing cell group) is clearly distinguishable in the ventrolateral region of the preoptic area in diurnal and nocturnal monkeys, as well as in humans. Galanin expression may serve to identify sleep-active neurons in the ventrolateral preoptic area of the mammalian brain. The VLPO appears to be a critical component of sleep circuitry across multiple species, and we hypothesize that shrinkage of the VLPO with advancing age may explain sleep deficits in elderly humans.

Expression of calcitonin gene-related peptide, substance P and protein kinase C in cultured dorsal root ganglion neurons following chronic exposure to mu, delta and kappa opiates

The mechanisms involved in morphine tolerance are poorly understood. It was reported by our group that calcitonin gene-related peptide (CGRP)-like immunoreactivity (IR) was increased in the spinal dorsal horn during morphine tolerance [Ménard et al. (1996) J. Neurosci. 16, 2342-2351]. More recently, we observed that it was possible to mimic these results in cultured dorsal root ganglion (DRG) neurons allowing for more detailed mechanistic studies [Ma et al. (2000) Neuroscience 99, 529-539]. The aim of the present series of experiments was to further validate the DRG cell culture model by establishing which subtypes of opioid receptors are involved in the induction of CGRP in cultured rat DRG neurons, and to examine the signaling pathway possibly involved in the induction of CGRP-like IR following repeated opiate treatments. Other neuropeptides known to be expressed in DRG neurons, such as substance P (SP), neuropeptide Y (NPY) and galanin, were investigated to assess specificity. Following treatment with any of the three opioid agonists (mu, DAMGO; delta, DPDPE; kappa, U50488H), the number of CGRP- and SP-IR cultured DRG neurons increased significantly, and in a concentration-dependent manner, with the effects of kappa agonist being less pronounced. NPY and galanin were not affected.Double-immunofluorescence staining showed that the three opioid receptors were co-localized with both CGRP- and SP-like IR.Protein kinase C (PKC)-like IR was found to be significantly increased following a repetitive treatment with DAMGO. Double-immunofluorescence staining showed the co-localization of PKCalpha with CGRP- and SP-IR in cultured DRG neurons. Moreover, a combined treatment with DAMGO and a PKC inhibitor (chelerythrine chloride or Gö 6976) was able to block the effects of the opioid on increased CGRP-like IR. These data suggest that the three opioid receptors may be involved in the induction of CGRP and SP observed following chronic exposure to opiates, and that PKC probably plays a role in the signaling pathway leading to the up-regulation of these neuropeptides. These findings further validate the DRG cell culture as a suitable model to study intracellular pathways that govern changes seen following repeated opioid treatments possibly leading to opioid tolerance.

Activation of a subset of lumbar spinothalamic neurons after copulatory behavior in male but not female rats

The precise pathways that convey copulation-related information to forebrain regions activated during male and female sexual behavior are poorly understood. Previous work from our laboratory and others has demonstrated the existence of a spinothalamic pathway that is a candidate to relay information to these areas. This pathway originates from a population of spinothalamic neurons in the lumbar spinal cord containing several neuropeptides including galanin, located in laminas 7 and 10 of the lumbar segments 3 and 4. To investigate the involvement of these lumbar spinothalamic neurons in conveying copulation-related information, we tested the hypothesis that these cells are activated after ejaculation in male rats and vaginocervical stimulation in female rats. This was assessed using galanin or cholecystokinin as a marker for this subset of spinothalamic neurons and Fos-immunoreactivity as a marker for neuronal activation. The results demonstrated that activation of these spinothalamic neurons is triggered by stimuli associated with ejaculation. Fos induction was specifically associated with ejaculation, because mounts or intromissions did not trigger expression. Moreover, these spinothalamic neurons were not activated by vaginocervical stimulation in female rats. Spinothalamic neurons have generally been associated with signaling pain and temperature information. The present findings demonstrate that a specific subpopulation of spinothalamic neurons signals information associated with ejaculation.

Characterization of afferent and efferent galanin-containing nerve fibres in the porcine ovary

Double-labelling immunofluorescence combined with retrograde tracing revealed three subpopulations of galanin-immunoreactive nerve fibres innervating the porcine ovary. The first group originated in ipsilateral dorsal root ganglia Th11-L5 and exhibited colocalization with substance P-, but not with tyrosine-hydroxylase- or dopamine-beta-hydroxylase-immunoreactivity. These fibres supplied primordial follicles and large arteries of the ovarian hilus. The second group, arising from the sympathetic inferior mesenteric ganglion, was galanin-immunoreactive, but non-reactive to substance P-, dopamine-beta-hydroxylase- or tyrosine-hydroxylase-antisera. Fibres of this type were sparsely distributed in the ovarian cortex. They were observed in connection with small cortical arterioles or in the ovarian cortical stroma. The third group of galanin-containing nerve terminals originated from postganglionic neurons located in sympathetic chain ganglia Th15-L3 and S1. Most of them contained tyrosine-hydroxylase- and dopamine-beta-hydroxylase-immunoreactivity. This subset of galanin-positive nerve fibres was the least frequent and was almost exclusively associated with cortical arterioles. The findings are indicative of an involvement of galanin in autonomic and sensory neuronal functions in the ovaries, possibly control of follicle maturation and blood flow.

Comparison of the cell immunophenotype of metastatic and primary foci in stage IV-S neuroblastoma

Neuroblastoma represents one of the most frequently developing malignant solid tumours in children. At the time of diagnosis, in more than half of the cases, metastatic cells are also present in the bone marrow. The present study was aimed at immunocytochemical analysis of selected neuropeptide manifestation in metastatic cells of neuroblastoma in bone marrow and at comparing the obtained results with the immunophenotype of parental neuroblastoma cells. The studies were performed on bone marrow material obtained from children treated at the Department of Paediatric Haematology and Oncology, University of Medical Sciences, Poznań, Poland, in 1998-2000. Immunocytochemical analysis of nervous tissue markers (employing the immunomax technique) involved 36 bone marrow preparations obtained from 27 children. The analysis included expression of neuron-specific enolase (NSE), PGP 9.5 protein, substance P (SP), chromogranin A (ChA), bombesin (B), galanin (G), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP). Close to 90% metastatic cells in bone marrow were found to exhibit NSE+SP+B+ phenotype and over a half of the cells manifested additionally expression of PGP 9.5+ChA+NPY+. Comparison of the obtained results with the immunophenotype of neuroblastoma cells obtained directly from the primary tumour demonstrated high correlation of NSE, SP and PGP 9.5 expression. Due to the relative ease of obtaining the bone marrow material and absence of neuromarkers in bone marrow metastatic cells in solid tumours other than neuroblastoma, determination of immunophenotype of the cells may represent a valuable supplementation in preliminary diagnosis of this tumour in children.

Distribution of cholecystokinin, calcitonin gene-related peptide, neuropeptide Y, and galanin in the primary gustatory nuclei of the goldfish

Cholecystokinin (CCK), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), and galanin all are known to have central effects on food intake. Immunocytochemistry was used to examine the presence of these substances within the primary gustatory nuclei of the goldfish, including the vagal lobe, which is a large, laminated structure composed of discrete sensory, fiber, and motor layers. The vagal lobes receive primary afferent input from the gustatory portion of the vagus nerve and contain reflex circuitry involved in the ingestion or rejection of potential food items. Immunohistochemistry indicates a heavy concentration of CCK-, CGRP-, NPY-, and galanin-immunoreactive fibers in the capsular fiber layer as well as in deeper sensory layers of the vagal lobe. CGRP immunoreactivity throughout the sensory layers and capsular immunoreactivity for CCK are greatly reduced 1-2 weeks following vagus nerve transection, indicating that the majority of these fibers are primary sensory afferents. In contrast, NPY and galanin immunoreactivity in the capsular fiber layer and reactivity for CCK, NPY, and galanin in the deeper sensory and fiber layers are relatively unaffected by vagus transection. CCK-, NPY-, and galanin-immunoreactive fibers and puncta also were present in the motor layers, as were CGRP-immunoreactive motor somata. CCK-immunoreactive cell bodies are present in layer III and layer VII/VIII of the vagal lobe and in the superficial granular layer of the lateral subnucleus of the commissural nucleus of Cajal, which is caudally contiguous with the vagal lobe.

Co-localization of histamine with GABA but not with galanin in the human tuberomamillary nucleus

The presence of GABA and galanin in histaminergic neurons was previously reported in the rodent brain but whether such co-localizations also occur in the human brain was not known. We used in situ hybridization histochemistry and immunohistochemistry to study the co-localization of histamine with GABA and galanin in neurons of the tuberomamillary nucleus of adult human posterior hypothalamus. On consecutive formalin-fixed paraffin-embedded sections, co-localization was assessed using the in situ hybridization for L-histidine decarboxylase mRNA and immunocytochemistry for glutamate decarboxylase-67 kDa or galanin in the two profiles of same cell. The pattern of distribution and number of histaminergic neurons identified by in situ hybridization of the synthesizing enzyme gene transcripts were in accordance with data reported for histamine immunoreactivity. The great majority of neurons within the main divisions of the tuberomamillary nucleus containing L-histidine decarboxylase mRNA was also immunoreactive for glutamate decarboxylase-67 kDa. The range of co-localization of the two markers varied from 72% in the lateral part, to 75-87% in the medial part and 83-88% in the ventral part. In contrast, no cell containing L-histidine decarboxylase mRNA was immunoreactive for galanin. We conclude that tuberomamillary neurons in human co-express histamine with GABA but, unlike the neurons in rodents, do not express galanin, indicating that neurotransmitter co-localization patterns differ in the two species.

Pancreatic tissue grafts are reinnervated by neuro-peptidergic and cholinergic nerves within five days of transplantation

The reinnervation process is crucial for the survival and functioning of cell, tissue or organ transplants. This study was designed to examine the exact time of reinnervation of intraocular pancreatic tissue transplants in rats. The rate of survival of neuropeptide-containing cells in pancreatic tissue grafts was also investigated. Calcitonin gene-related peptide (CGRP), galanin (GAL), neuropeptide Y (NPY) were observed in the surviving nerve cell bodies of the grafts. The iridal nerves reinnervating the pancreatic grafts expressed CGRP, GAL, NPY and choline-acetyl-transferase (ChAT) on day 5, and tyrosine hydroxylase (TH) and nitric oxide synthase (bNOS) on day 6 of the transplantation period. The expression of CGRP in the reinnervating nerves was more consistent when compared to GAL, NPY, ChAT, TH and bNOS. Although all of the three neuropeptides (CGRP, GAL, NPY) were present in the surviving nerve cell bodies of the pancreatic tissue graft up to the end (day 9) of the transplantation period, the number of CGRP-immunopositive cells was consistently higher throughout the transplantation period. Hence, the number of CGRP-positive cells in the pancreatic tissue graft was significantly (P < 0.05) higher than that of GAL and NPY. In conclusion, pancreatic fragments were reinnervated by neuropeptidergic (CGRP, NPY) and cholinergic (ChAT) nerves within the first 5 days of transplantation. In addition to the reinnervation of pancreatic tissue grafts, the intrinsic neurones of the grafts also survived after transplantation. The rate of survival of CGRP-containing cells in the pancreatic tissue grafts was more consistent compared to that of NPY and GAL.

Uterus-innervating neurones of paracervical ganglion in the pig: immunohistochemical characteristics

Immunohistochemical characteristics of neurones innervating the porcine uterus located in paracervical ganglia were studied with a combination of retrograde fluorescent tracing and immunofluorescence. Retrograde fluorescent tracer Fast Blue (FB) was injected into the uterine horn and uterine cervix. The presence of biologically active substances, tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), galanin (GAL), Met-enkephalin-Arg-Gly-Leu (MEAGL) and calcitonin gene-related peptide (CGRP) was studied in FB-positive neurones localised in paracervical ganglia. FB-positive neurones containing TH, NPY, VIP and MEAGL were numerous, while those containing CGRP were scarce. The results pointed to some species-related differences in immunohistochemical coding of neurones of paracervical ganglion responsible for uterus innervation.

Galanin in human pituitary adenomas: frequency and clinical significance

OBJECTIVES

Galanin (GAL) is a neuropeptide widely expressed in the central and peripheral nervous system and in neuroendocrine tissue, including the adenohypophysis where, in humans, it is expressed in corticotrophs and in ACTH-producing adenomas. Previous analyses of human tissue have used antiserum against porcine GAL for detection of GAL immunoreactivity (GAL-IR) and no pathophysiological correlates have been reported. Given significant differences between the sequence of porcine and human GAL peptides, the aim of this study was to use antiserum raised against synthetic human GAL to investigate GAL-IR in non tumorous pituitaries and in pituitary adenomas, and to correlate GAL-IR with the clinical and hormonal characteristics of patients with Cushing's disease.

PATIENTS

Six nontumorous pituitaries were obtained from autopsy and 151 pituitary adenomas, comprising 62 functioning (16 corticotroph, 26 somatotroph, 19 lactotroph and one thyrotroph) and 89 nonfunctioning adenomas, were obtained by surgery.

RESULTS

All non tumorous pituitary glands showed GAL-IR in corticotrophs, in basophil cells within the neurohypophysis and in nerve fibres of the neurohypophysis. GAL-IR was found in a subset (10 of 16) of patients with ACTH-secreting tumours causing Cushing's syndrome. GAL-IR was rarely expressed in somatotroph adenomas and prolactinomas, but was expressed in approximately one-third of nonfunctioning tumours. GAL-IR was found in almost 90% of nonfunctioning tumours that were positive for ACTH. There were no significant differences in sex ratio, age at presentation or 24-h urinary free cortisol secretion in the subset of patients with Cushing's disease positive (n = 10) or negative (n = 6) for GAL-IR. However, Cushing's patients positive for GAL-IR tended to have smaller tumours and achieved a higher cure rate than those without (100 vs. 50%, P = 0.017).

CONCLUSIONS

Galanin is present in normal and tumorous human pituitaries. In addition, GAL colocalizes exclusively in corticotrophs of normal pituitaries and is coexpressed almost exclusively in corticotrophs from functioning and nonfunctioning tumours. The finding that corticotroph adenomas can function irrespective of the presence of GAL suggests that GAL may not play a pathophysiological role in Cushing's disease. However, the better surgical outcome observed in patients with Cushing's disease who had tumours positive for GAL-IR suggests that the expression of GAL confers a less aggressive tumour phenotype.

Sexually dimorphic activation of galanin neurones in the ferret's dorsomedial preoptic area/anterior hypothalamus after mating

Male ferrets in breeding condition possess three times as many galanin-immunoreactive (IR) neurones as oestrous females in the sexually dimorphic dorsomedial preoptic area/anterior hypothalamus (dmPOA/AH). Using Fos-IR as a marker of activation, we investigated whether mating with intromission differentially activates this sexually dimorphic group of galanin-IR neurones in male and female ferrets. Male ferrets that intromitted had a significantly greater percentage of galanin-IR neurones in the dmPOA/AH that were colabelled with nuclear Fos-IR than oestrous females that received an intromission. Intromissive stimulation augmented Fos-IR in an equal percentage of galanin-IR neurones in both sexes in the medial amygdala (MA) and bed nucleus of the stria terminalis (BNST). Peripheral anosmia induced by bilateral occlusion of males' nares did not reduce the mating-induced activation of galanin-IR neurones in the dmPOA/AH, and there was a significant correlation among individual males between intromission duration and the percentage of dmPOA/AH galanin-IR neurones colabelled with Fos-IR. Exposure of castrated, testosterone propionate-treated male ferrets to either soiled bedding or to volatile odours from oestrous females failed to induce nuclear Fos-IR in galanin-IR neurones located in the dmPOA/AH, BNST or MA, suggesting that the mating-induced activation of galanin-IR forebrain neurones in male ferrets depends more on genital-somatosensory than on olfactory inputs. The observed sex dimorphism in the mating-induced activation of galanin-IR neurones in the dmPOA/AH raises the possibility that these neurones perform a mating-dependent function that occurs only in males.