Location of substance P-, bombesin-gastrin-releasing peptide, [Met5]enkephalin- and [Met5]enkephalin-Arg6-Phe7-like immunoreactivities in adult human sympathetic ganglia

Protective effect of RC-3095, an antagonist of the gastrin-releasing peptide receptor, in experimental arthritis

OBJECTIVE

To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved.

METHODS

RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1β, and tumor necrosis factor α (TNFα) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA.

RESULTS

In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1β, and TNFα, and showed a diminished expression of GRPR.

CONCLUSION

These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

Localization and expression of gastrin-releasing peptide (GRP) in the bovine cervix

Gastrin-releasing peptide (GRP) has been suggested as a novel regulatory peptide in the female reproductive tract but the presence of GRP and GRP mRNA in the non-neurogenic tissue of the cervix has not yet been clarified. In the present study, immunohistochemistry and in situ hybridization were used to reveal the distribution of GRP immunoreactivity and expression of GRP mRNA in the bovine cervix. The cervixes from 21 non-pregnant and 20 pregnant cows, and 6 fetuses were used in the study. In the fetus, adult non-pregnant and pregnant specimens, GRP and GRP mRNA were predominantly detected in the luminal epithelial cells of basal areas of peripheral regions of the cervix. Positive staining of GRP in the epithelial cells of the cervix was first detected in the CRL 37 cm of the fetus. During the estrous cycles, the staining intensity of GRP in the epithelial cells was stronger in the follicular phase than in the luteal phase. During the early gestational period, GRP immunoreactivity was detected at relatively similar intensity to the follicular phase. In situ hybridization results ascertained the expression of GRP mRNA in the superficial epithelial cells of the cervix of non-pregnant and pregnant cows. The results suggest that GRP may be important both in the development of the fetal cervix and secretory activity of the epithelial cells of the cervix.

Unusual autonomic ganglia: connections, chemistry, and plasticity of pelvic ganglia

The pelvic ganglia provide the majority of the autonomic nerve supply to reproductive organs, urinary bladder, and lower bowel. Of all autonomic ganglia, they are probably the least understood because in many species their anatomy is particularly complex. Furthermore, they are unusual autonomic ganglia in many ways, including their connections, structure, chemistry, and hormone sensitivity. This review will compare and contrast the normal structure and function of pelvic ganglia with other types of autonomic ganglia (sympathetic, parasympathetic, and enteric). Two aspects of plasticity in the pelvic pathways will also be discussed. First, the influence of gonadal steroids on the maturation and maintenance of pelvic reflex circuits will be considered. Second, the consequences of nerve injury will be discussed, particularly in the context of the pelvic ganglia receiving distributed spinal inputs. The review demonstrates that in many ways the pelvic ganglia differ substantially from other autonomic ganglia. Pelvic ganglia may also provide a useful system in which to study many fundamental neurobiological questions of broader relevance.

Localization, regulation and functions of neurotransmitters and neuromodulators in cervical sympathetic ganglia

Cervical sympathetic ganglia represent a suitable model for studying the establishment and plasticity of neurochemical organization in the nervous system since sympathetic postganglionic neurons: (1) express several neuromediators, i.e., short acting transmitters, neuropeptide modulators and radicals, in different combinations; (2) receive synaptic input from a limited number of morphologically and neurochemically well-defined neuron populations in the central and peripheral nervous systems (anterograde influence on phenotype); (3) can be classified morphologically and neurochemically by the target they innervate (retrograde influence on phenotype); (4) regenerate readily, making it possible to study changes in neuromediator content after axonal lesion and their possible influence on peripheral nerve regeneration; (5) can be maintained in vitro in order to investigate effects of soluble factors as well as of membrane bound molecules on neuromediator expression; and (6) are easily accessible. Acetylcholine and noradrenaline, as well as neuropeptides and the recently discovered radical, nitric oxide, are discussed with respect to their localization and possible functions in the mammalian superior cervical and cervicothoracic (stellate) paravertebral ganglia. Furthermore, mechanisms regulating transmitter synthesis in sympathetic neurons in vivo and in vitro, such as soluble factors, cell contact or electrical activity, are summarized, since modulation of transmitter synthesis, release and metabolism plays a key role in the neuronal response to environmental influences.

Immunohistochemical correlation of human adrenal nerve fibres and thoracic dorsal root neurons with special reference to substance P

Applying a double-labelling immunofluorescence technique, six types of substance P-containing nerve fibres were distinguished in the human adrenal gland according to the immunohistochemical colocalization of (I) calcitonin gene-related peptide (CGRP), (II) cholecystokinin, (III) nitric oxide synthase, (IV) dynorphin, (V) somatostatin, and (VI) vasoactive intestinal polypeptide. Fibre populations I to IV in their mediator content resembled the respective subpopulations of primary sensory neurons in human thoracic dorsal root ganglia, while populations V and VI revealed no correspondence with dorsal root neurochemical coding. Nerve fibres with the combination substance P/nitric oxide synthase occurred only in the adrenal cortex, whereas all other fibre types were present in both cortex and medulla. As revealed by immuno-electron microscopy, substance P-immunolabelled axon varicosities (a) exhibited synaptic contacts with medullary chromaffin cells or with neuronal dendrites, (b) were directly apposed to cortical steroid cells and (c) were separated from fenestrated capillaries only by the interstitial space. These findings provide immunochemical support for an assumed sensory innervation of the human adrenal gland, and additionally suggest participation of substance P in efferent autonomic pathways. Furthermore, the results are indicative for a differentiated involvement of substance P in the direct and indirect regulation of neuroneuronal and neuroendocrine interactions.

Immunohistochemical localization of neuropeptides in the porcine thoraco-lumbar paravertebral ganglia

The existence and distribution pattern of neuropeptide Y, Met5-enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide, calcitonin gene-related peptide, substance P and bombesin/gastrin releasing peptide in the neuronal elements of the thoracolumbar paravertebral ganglia (T4-L6) were studied immunohistochemically in sexually immature female pigs. Subpopulations of nerve cell bodies containing immunoreactivity to neuropeptide Y, Met5-enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide and calcitonin gene-related peptide were described. However, neurons were non-immunoreactive for substance P and bombesin/gastrin releasing peptide. The solitary small intensely fluorescent cells contain calcitonin gene-related peptide-, substance P- and Met5-enkephalin-Arg6-Gly7-Leu8-, whereas the some cells in clusters contained only substance P and only substance P and Met5-enkephalin-Arg6-Gly7-Leu8. Immunoreactivities to all studied peptides occurred in the nerve fibres within investigated ganglia. Additionally the number of nerve fibres containing particular peptides as well as their distribution pattern were found to vary. The results of this study were compared with those of previous investigations in other species.

Distribution of neuropeptides in the porcine stellate ganglion

The localization and distribution of neuropeptides including neuropeptide Y (NPY), [Met5]enkephalin-Arg6-Gly7-Leu8 (MEAGL), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), substance P and somatostatin (SOM) were analyzed in the stellate ganglion of the pig by use of the indirect immunofluorescence technique. NPY, MEAGL, SOM, VIP and CGRP immunoreactivities were found to exist in subpopulations of neuronal cell bodies of the stellate ganglion. A population of the small intensely fluorescent (SIF) cells showed MEAGL immunoreactivity. In addition, the presence of NPY-, MEAGL-, CGRP-, SP-, SOM- and VIP-immunoreactive nerve fibers and axonal varicosities were observed in the stellate ganglion. The localization and pattern of distribution of these peptides in the porcine stellate ganglion were compared with studies carried out on stellate ganglia of other mammalian species.

Comparison of immunohistochemical localization of [Met5] enkephalin-Arg6-Gly7-Leu8, vasoactive intestinal polypeptide and tyrosine hydroxylase in the major pelvic ganglion of the rat

The major pelvic ganglion is an autonomic ganglion containing both sympathetic and parasympathetic postganglionic neuronal cell bodies. The existence of the proenkephalin A-derived peptide [Met5]enkephalin-Arg6-Gly7-Leu8 immunoreactivity in the rat major pelvic ganglion has been described quite recently. The aim of this study was to compare the relations of [Met5]enkephalin-Arg6-Gly7-Leu8-containing postganglionic neurons and nerve fibers to noradrenergic (tyrosine hydroxylase-immunoreactive) and non-noradrenergic (putative cholinergic) neurons of the rat major pelvic ganglion. Immunohistochemical double staining and elution-restaining techniques were used to investigate the distribution of [Met5]enkephalin-Arg6-Gly7-Leu8 in correlation with tyrosine hydroxylase and vasoactive intestinal polypeptide. The major pelvic ganglion contained neurons immunoreactive either for tyrosine hydroxylase or vasoactive intestinal polypeptide. Many principal neurons, however, were immunoreactive for tyrosine hydroxylase nor vasoactive intestinal polypeptide. [Met5]Enkephalin-Arg6-Gly7-Leu8-immunoreactive principal neurons formed a minor subpopulation in the ganglion and were not immunoreactive for tyrosine hydroxylase. The majority of [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive principal cells were non-immunoreactive for vasoactive intestinal polypeptide, but a few of them also contained vasoactive intestinal polypeptide. In contrast to the large [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive principal neurons, which formed a population of non-noradrenergic (putative cholinergic) cells, the small [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive cell exhibited intense tyrosine hydroxylase immunofluorescence and represented a subpopulation of small, intensely fluorescent cells. [Met5]Enkephalin-Arg6-Gly7-Leu8-immunoreactive pericellular fiber plexuses were found around tyrosine hydroxylase- and vasoactive intestinal polypeptide-immunoreactive principal neurons and in association with small intensity fluorescent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuropeptides in the human celiac/superior mesenteric ganglionic complex: an immunohistochemical study

The occurrence of vasoactive intestinal polypeptide (VIP), peptide histidine-isoleucine (PHI), calcitonin gene-related peptide (CGRP), substance P (SP), somatostatin (SOM), galanin (GAL) and enkephalins (ENK) is studied in the human celiac/superior mesenteric ganglionic complex of pre- and full-term newborns, and adult subjects by means of immunohistochemistry. The antisera used labelled nerve fibres and terminal-like networks for each examined peptide, as well as VIP- and SOM-positive postganglionic neurons. Differences in the relative amount and density of the structures immunoreactive to the various peptides were observed. Moreover, variations in the amount and type of labelled elements were appreciable for each peptide when specimens from subjects at perinatal and adult ages were compared. Double-labelling immunofluorescence for SP and each other peptide showed that co-localization with SP is very frequent for CGRP, moderate to scarce for GAL and SOM, and rare to absent for PHI, VIP and ENK. VIP-, ENK- and CGRP-immunolabeled perikarya bearing the morphological features of the small intensely fluorescent (SIF) cells occurred in the organ. The presence of a paraganglion in one of the specimens examined allowed the detection of VIP- and ENK-positive cell bodies and VIP-, ENK-, SP- and GAL-like immunoreactive varicose nerve fibres in it. The results obtained provide substantial morphological data in support of the involvement of the examined peptides in the chemical interneuronal signalling in the human celiac/superior mesenteric ganglia.

The effects of neuropeptides on mucous glycoprotein secretion from human nasal mucosa in vitro

The role of neuropeptides in the regulation of macromolecule secretion from human nasal mucosa is incompletely understood. Previous in vitro explant culture studies have demonstrated the effects of neuropeptides on lactoferrin release from serous cells and 3H-glucosamine labeled respiratory glycoconjugate secretion from mucus-containing cells. The generation of a new monoclonal antibody, 7F10, has led to the development of an ELISA for high molecular weight respiratory mucous glycoproteins (MGP). This ELISA was used to measure the ability of sensory, parasympathetic and sympathetic neuropeptides to stimulate MGP release from human nasal mucosal fragments in short term explant culture in vitro. Significant MGP release was stimulated by the sensory neuropeptides gastrin releasing peptide (10 microM GRP: 10.6% +/- 2.4% increase, n = 8, P less than 0.01 vs. control), substance P (1 microM SP: 12.5% +/- 5.4%, n = 11, P less than 0.05), neurokinin A (1 microM NKA: 17.8 +/- 4.3%, n = 6, P less than 0.01), while calcitonin gene related peptide (CGRP) was without effect. Vasoactive intestinal peptide (VIP), a neurotransmitter from parasympathetic nerves, induced significant dose dependent MGP secretion, but had no additive or inhibitory interaction with methacholine-induced secretion. Neuropeptide Y (NPY), present in sympathetic nerves, had no effect on MGP secretion. These observations correlate with the effects of neuropeptides on serous cell lactoferrin secretion, and the presence of specific GRP, SP, and VIP binding sites on human nasal submucosal glands that have been detected by autoradiography. GRP and tachykinins (SP and NKA) from sensory nerves, and VIP released during parasympathetic reflexes may significantly stimulate mucous and serous cell secretion from human nasal mucosa in vivo.

Does failed natural opioid modulation in regional sympathetic ganglia cause reflex sympathetic dystrophy?

Early features of reflex sympathetic dystrophy in a limb resemble the general effects of autonomic arousal associated with opioid withdrawal. It is suggested that natural opioid peptide modulation in regional sympathetic ganglia normally rises to prevent excessive autonomic activity in an injured limb. After an injury (especially a trivial one) to a susceptible subject, this localised increase in opioid modulation may fail or may rapidly wane so that autonomic features of opioid withdrawal appear in the affected limb. Florid dystrophic changes may then occur because of passive complications of disuse associated with pain, or as a result of more active processes. Preservation of an appropriate opioid bias in the regional sympathetic ganglia might be an important factor in the successful management and prevention of reflex sympathetic dystrophy.

Immunohistochemical quantification of substance P in spinal dorsal horns of patients with multiple system atrophy

Using a computer-assisted image analyser, an immunohistochemical quantification method of substance P-like immunoreactivity (SPLI) in laminae I + II of spinal dorsal horn was established and applied to 13 patients with multiple system atrophy (MSA) with no disturbance of pain sensation, including olivo-ponto-cerebellar atrophy and striatonigral degeneration, and 13 neurologically normal controls. To investigate whether alteration of SPLI is related to an autonomic disorder, myelinated fibre counts of the fourth thoracic ventral roots were performed. Eleven of 13 MSA patients showed a significant decrease in small and large myelinated fibres, and were diagnosed with definite Shy-Drager syndrome (SDS), with the exception of two who had no apparent history of autonomic dysfunction. SPLIs in laminae I + II in 10 of these 11 patients, when adjusted for age, were significantly decreased at both levels of the fourth thoracic and third lumbar spinal segments. The results suggest the disorder of SP-containing synapses of primary afferent neurons and/or those of interneurons in SDS.

Source of Stress-Induced Increase in Plasma Met-Enkephalin in Rats: Contribution of Adrenal Medulla and/or Sympathetic Nerves*

Abstract The contribution of the adrenal medulla and/or the sympathetic nerves to the plasma levels of Met-enkephalin was investigated. Rats were divided into four groups: sham-operated/saline, sham-operated/guanethidine, adrenal-demedullated/saline, demedulla-ted/guanethidine. After 4 weeks of injection with either saline or guanethidine (25 mg/kg/day), animals were cannulated in the left carotid artery for blood sampling. Three days later, blood samples were taken before and at 2 and 30 min of restraint stress. Adrenal demedullation lowered basal plasma epinephrine levels markedly and prevented entirely the increase induced by restraint stress. Chronic guanethidine treatment lowered basal plasma norepinephrine levels and decreased the response to stress. Guanethidine treatment increased the basal plasma epinephrine level without affecting the response to stress. The combination of guanethidine plus adrenal demedullation lowered basal plasma concentrations of all three catecholamines and further attenuated the norepinephrine response. Restraint stress increased plasma native and peptidase-derivable Met-enkephalin. Adrenal demedullation, resulting in greater than 95% depletion of adrenal catecholamines and significant depletion of adrenal Met-enkephalin, did not inhibit the stress-induced increase in plasma Met-enkephalin, and in fact, was associated with a potentiated response to stress. Guanethidine treatment with or without demedullation increased baseline plasma native Met-enkephalin and abolished the stress-induced increase in plasma native and peptidase-derivable Met-enkephalin. Thus, the stress-induced increase in plasma Metenkephalin results from release from sympathetic nerves, rather than adrenal medulla. However, the sympathetic nerves and adrenal medulla together do not appear to account entirely for basal concentrations of circulating Met-enkephalin. Hepatic portal vein plasma concentration of native Met-enkephalin was greater than that in the carotid artery, suggesting contribution from the gastrointestinal tract; however, evisceration did not decrease plasma native Met-enkephalin. Some compensatory mechanism results in elevation of basal plasma native Met-enkephalin in sympathectomized rats. Also, in the absence of the adrenal medulla there is a compensatory increase in the amount of Met-enkephalin released into the circulation in response to stress.

Gastrin-releasing peptide in human nasal mucosa

Gastrin-releasing peptide (GRP), the 27 amino acid mammalian form of bombesin, was studied in human inferior turbinate nasal mucosa. The GRP content of the mucosa measured by radioimmunoassay was 0.60 +/- 0.25 pmol/g tissue (n = 9 patients; mean +/- SEM). GRP-immunoreactive nerves detected by the immunogold method of indirect immunohistochemistry were found predominantly in small muscular arteries, arterioles, venous sinusoids, and between submucosal gland acini. 125I-GRP binding sites determined by autoradiography were exclusively and specifically localized to nasal epithelium and submucosal glands. There was no binding to vessels. The effects of GRP on submucosal gland product release were studied in short-term explant culture. GRP (10 microM) significantly stimulated the release of the serous cell-specific product lactoferrin, and [3H]glucosamine-labeled glycoconjugates which are products of epithelial goblet cells and submucosal gland cells. These observations indicate that GRP released from nerve fibers probably acts on glandular GRP receptors to induce glycoconjugate release from submucosal glands and epithelium and lactoferrin release from serous cells, but that GRP would probably not affect vascular permeability.

Immunocytochemical analysis of [Met5]enkephalin-Arg6-Gly7-Leu8 immunoreactive structures in the rat superior cervical ganglion

Indirect immunofluorescence and immunoelectron microscopy were employed to analyze the enkephalinergic systems in the rat superior cervical ganglion (SCG). These systems were identified using specific antiserum against [Met5]Enkephalin-Arg6-Gly7-Leu8 (ENK-8), a peptide which is derived only from proenkephalin A. Abundant ENK-8 like immunoreactive (ENK-8-LI) neurons and fibers were observed in the SCG, but their distribution patterns were heterogenous; ENK-8-LI neurons were localized preferentially in the caudal two-thirds of the SCG, while immunoreactive fibers were found to be distributed more densely in the rostral one-third than in the remaining part of the SCG. Most of the ENK-8-LI neurons were large and had ultrastructural features resembling those of principal cells, some were identified electron microscopically as small intensely fluorescent (SIF) cells. ENK-8-LI fibers were varicose in appearance and surrounded the perikarya of neurons. Since most of these fibers were not detected after experimental decentralization of the SCG and since ENK-8-LI terminals were seen to contain small lucent vesicles, most of the former were thought to be preganglionic fibers. Immunoreactive fibers mainly formed synaptic contacts with the dendrites of non-immunoreactive principal cells, but a small proportion of ENK-8-LI principal cells also received synaptic input from them. Occasionally, immunoreactive fibers formed synapses with the processes or the soma of both ENK-8-LI and non-immunoreactive SIF cells. On the basis of these findings, we conclude that: (1) preganglionic ENK-8-LI fibers terminate mainly on the principal cells, which are devoid of ENK-8-LI structures; (2) the majority of ENK-8-LI neurons are principal cells, while the remainder are SIF cells; (3) inputs to these cells mainly involve structures lacking ENK-8 immunoreactivity; and (4) there are, however, a small number of ENK-8-LI preganglionic fibers which terminate on ENK-8-LI principal cells and SIF cells.

Distribution and origin of peptide-containing nerve fibers in the celiac superior mesenteric ganglion of the guinea-pig

The origin of the peptidergic nerve fibers and terminals in the celiac superior mesenteric ganglion of the guinea-pig was studied. The distribution of immunoreactivity to enkephalin, substance P, calcitonin gene-related peptide, cholecystokinin, vasoactive intestinal polypeptide/peptide histidine isoleucine, bombesin and dynorphin was analysed in intact animals and in animals subjected to various denervation and ligation procedures. The present results show that each of the connected nerve trunks carries peptidergic pathways and contributes to the peptidergic networks in the celiac superior mesenteric ganglion. Thus, the thoracic splanchnic nerves contain enkephalin-, substance P- and calcitonin gene-related peptide-immunoreactivity of which substance P and calcitonin gene-related peptide coexist in the same nerve fibers. In addition, cholecystokinin-, vasoactive intestinal polypeptide/peptide histidine isoleucine- and dynorphin-immunoreactivity is present in some fibers. All of these immunoreactivities are present in sensory neurons except enkephalin which probably originates in the spinal cord. The mesenteric nerves carry enkephalin-, calcitonin gene-related peptide-, cholecystokinin-, vasoactive intestinal polypeptide/peptide histidine isoleucine-, bombesin- and dynorphin-immunoreactive fibers from the intestine and are the main source for cholecystokinin, vasoactive intestinal polypeptide/peptide histidine isoleucine, bombesin and dynorphin fibers. Double-staining experiments indicate that many of these peptides are synthesized in the same enteric neurons. Also the intermesenteric nerve contains peptide-immunoreactive fibers to the celiac superior mesenteric ganglion from different sources, probably including the distal colon as well as dorsal root ganglia and spinal cord at lower thoracic and lumbar levels. The results are discussed in relation to earlier morphological and physiological studies supporting the view of a role of the celiac superior mesenteric ganglion in local reflex mechanisms involved in regulation of gastrointestinal functions.

Age-related changes of enkephalinergic innervation of human sympathetic neurons

The age-related changes in the distribution of enkephalin-immunoreactive (ENK-IR) nerve fibers in relation to the principal neurons were studied in 23 human sympathetic ganglia from patients aged between 22 and 98 years. There were no age-related changes in the diameter of nerve cells and the packing density of the neurons did not change. There was an age-related decrease in the proportion of neurons innervated by enkephalin-containing fibers. In all age groups the neurons innervated by ENK-IR nerve fibers were larger than those neurons which were not surrounded by ENK-IR nerves. The pigment material in the enkephalin-innervated neurons was non-osmiophilic. The small neurons containing dark neuromelanin type of age pigment were not innervated by ENK-IR nerves. It is speculated that ENK-IR preganglionic nerves play a role in maintaining neuronal integrity of sympathetic neurons.

Decreased expression of neuropeptides in malignant paragangliomas: an immunohistochemical study

Paraffin-embedded sections of 99 human adrenal and extraadrenal paragangliomas were analyzed by the indirect immunoperoxidase technique for the presence of neuron-specific enolase (NSE) and 10 neuropeptides. Each showed diffuse staining for NSE. Most tumors were positive for [Leu5]-enkephalin (76 per cent), [Met5]-enkephalin (75 per cent), somatostatin (67 per cent), and pancreatic polypeptide (51 per cent), followed by vasoactive intestinal polypeptide (VIP) (43 per cent), substance P (31 per cent), ACTH (28 per cent), calcitonin (23 per cent), bombesin (15 per cent), and neurotensin (12 per cent). The neuropeptides paralleled to a large extent those normally found in the sympathetic nervous system. Clinically malignant paragangliomas (n = 25) with proven regional or distant metastases expressed considerably fewer neuropeptides, although the spectrum of those seen remained similar. Malignant paragangliomas contained an average of two neuropeptides per tumor, in contrast to five for the benign tumors (P less than 0.05). Logistic regression analysis of staining results revealed that the paucity of enkephalins, somatostatin, pancreatic polypeptide, and VIP along with the patient's sex was predictive of clinical malignancy. Our results show a definite relationship between expression of neuropeptides and the biologic behavior of these paragangliomas.

Two immunohistochemically identified populations of calcitonin gene-related peptide (CGRP)-immunoreactive axons in human skin

Double labelling immunofluorescence has shown two populations of unmyelinated sensory axons in human skin that contain immunoreactivity (IR) to calcitonin gene-related peptide (CGRP). One population also contains IR to substance P (SP), whilst the other also contains IR to somatostatin (SOM). Axons containing both CGRP-IR and SOM-IR comprised more than 75% of CGRP-IR axons associated with the epidermis; the rest of the CGRP-IR axons contained SP-IR. No axons contained both SP-IR and SOM-IR. Some dermal blood vessels were surrounded by axons containing both CGRP-IR and SP-IR, but most CGRP-IR perivascular axons contained SOM-IR without SP-IR. Sweat glands were well supplied with sensory axons containing CGRP-IR and weak SOM-IR but not SP-IR. Therefore, CGRP is a histochemical marker for a larger number of unmyelinated cutaneous afferents in human skin than is SP. CGRP itself may have a role in the mediation of responses to stimulation of at least two populations of sensory axons.

[Met5]enkephalin-Arg6-Phe7- and [Met5]enkephalin-Arg6-Gly7-Leu8-immunoreactive nerve fibres and neurons in the superior cervical ganglion of the rat

[Met5]enkephalin-Arg6-Phe7-(MEAP-) and [Met5]enkephalin-Arg6-Gly7-Leu8-(MEAGL-) immunoreactivity was studied by indirect immunohistochemistry in the superior cervical ganglion of the rat with specific antisera produced in rabbits against the corresponding synthetic opioid peptides. Several MEAP- and a few MEAGL-immunoreactive principal nerve cells were observed in the ganglion, while the small intensely fluorescent cells appeared as non-reactive. The superior cervical ganglion also contained dense networks of MEAP- and MEAGL-immunoreactive nerve fibres, which often formed basket-like structures around the principal nerve cells and small intensely fluorescent cells. After ligation of the preganglionic nerve trunk with simultaneous transection of the main postganglionic trunks, a distinct accumulation of both MEAP- and MEAGL-immunoreactivity was observed on both sides of the ligature. Ligation of the preganglionic nerve trunk caused a marked decrease in the number of both MEAP- and MEAGL-immunoreactive nerve fibres in the ganglion. Ligation of the main postganglionic nerve trunks with simultaneous preganglionic nerve division resulted in accumulation of MEAP- and MEAGL-immunoreactive material on the ganglionic side of the ligature in both the external and internal carotid nerve. After division of both the pre- and postganglionic nerve trunks, some immunoreactive nerve fibres and principal nerve cells were still observed in the ganglion. A few immunoreactive neurons and nerve fibres were also observed in the ganglion stellatum. A large number of MEAP- and MEAGL-immunoreactive nerve fibres was detected in the spinal cord at the levels C6-Th6. A few neurons in the intermediolateral cell column of the spinal cord at levels C8-Th1 showed MEAP- but not MEAGL-immunoreactivity. The cultured superior cervical ganglion contained a few MEAP-immunoreactive neurons, and the fibre outgrowth showed immunoreactivity both to MEAP and MEAGL. In electron microscopy, MEAGL-immunoreactivity in the superior cervical ganglion was localized in nerve fibres containing neurotubules and in principal nerve cells. The present results demonstrate that the rat superior cervical ganglion contains both extrinsic and intrinsic MEAP- and MEAGL-immunoreactive nerve fibres. Most of these fibres are of preganglionic origin. Both the principal nerve and small intensely fluorescent cells are often surrounded by MEAP- or MEAGL-immunoreactive nerve fibres and may receive innervation by these fibres. Several ganglionic neurons projecting to the sympathetic target tissues show MEAP- and/or MEAGL-immunoreactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Met]- and [Leu]enkephalin-like immunoreactive cell bodies and nerve fibres in the coeliac ganglion of the cat

The occurrence and distribution of methionine- and leucine-enkephalin-like immunoreactivity were investigated in the cat coeliac ganglion using either the indirect immunoperoxidase method or the peroxidase-antiperoxidase technique. Several antisera raised to methionine- and leucine-enkephalin were used. Their specificity was assessed by incubating sections of the coeliac ganglion with increasing dilutions of antisera and with antisera saturated with their respective antigen. The present study was performed both in untreated and in colchicine-treated cats. Immunoreactive methionine- and leucine-enkephalin-like cell bodies were only visualized in colchicine-treated cats. Two types of labeled cells were observed. The first type had a size similar to that of unlabeled principal ganglion cells. These labeled cells were numerous and scattered throughout the ganglion; they probably represented enkephalin-containing ganglion cells. The second type of immunoreactive cells were of a much smaller size. They were always gathered in small clusters of about 5-15 cells and were not numerous; they presumably represented enkephalin-containing small intensely fluorescent cells. Immunoreactive nerve fibres were mainly observed in untreated cats and accessorily in colchicine-treated cats. In untreated animals dense networks of methionine- and leucine-enkephalin-like immunoreactive fibres were found in the coeliac ganglion. These fibres had numerous varicosities which often closely surrounded unlabeled principal ganglion cells. In colchicine-treated cats some immunoreactive fibres surrounded labeled principal ganglion cell bodies. The present results establish for the first time the presence of enkephalin-like immunoreactive principal ganglion cells in a mammalian sympathetic prevertebral ganglion. The presence of enkephalin-containing principal ganglion cells, small intensely fluorescent cells and nerve terminals, supports an important role of enkephalins in the integrative synaptic activities of cat coeliac ganglion cells.