Regional distribution of neuropeptide Y and its receptor in the porcine central nervous system

The regional distribution of neuropeptide Y (NPY) immunoreactivity and receptor binding was studied in the porcine CNS. The highest amounts of immunoreactive NPY were found in the hypothalamus, septum pellucidum, gyrus cinguli, cortex frontalis, parietalis, and piriformis, corpus amygdaloideum, and bulbus olfactorius (200-1,000 pmol/g wet weight). In the cortex temporalis and occipitalis, striatum, hippocampus, tractus olfactorius, corpus mamillare, thalamus, and globus pallidus, the NPY content was 50-200 pmol/g wet weight, whereas the striatum, colliculi, substantia nigra, cerebellum, pons, medulla oblongata, and medulla spinalis contained less than 50 pmol/g wet weight. The receptor binding of NPY was highest in the hippocampus, corpus fornicis, corpus amygdaloideum, nucleus accumbens, and neurohypophysis, with a range of 1.0-5.87 pmol/mg of protein. Intermediate binding (0.5-1.0 pmol/mg of protein) was found in the septum pellucidum, columna fornicis, corpus mamillare, cortex piriformis, gyrus cinguli, striatum, substantia grisea centralis, substantia nigra, and cerebellum. In the corpus callosum, basal ganglia, corpus pineale, colliculi, corpus geniculatum mediale, nucleus ruber, pons, medulla oblongata, and medulla spinalis, receptor binding of NPY was detectable but less than 0.5 pmol/mg of protein. No binding was observed in the bulbus and tractus olfactorius and adenohypophysis. In conclusion, immunoreactive NPY and its receptors are widespread in the porcine CNS, with predominant location in the limbic system, olfactory system, hypothalamoneurohypophysial tract, corpus striatum, and cerebral cortex.

Iodinated-NPY binding sites: autoradiographic study in the rat brain

Several authors have described the presence of iodinated neuropeptide-Y binding sites on membranes of the mammalian CNS. In the present study we show a mapping of iodinated-NPY binding sites in the rat brain using receptor autoradiography. The sections were incubated with 125I-Bolton-Hunter coupled NPY (0.5-03 nM), in the absence or presence of 1 microM cold NPY. Some autoradiograms are studied by means of an image analyzer (VDC 501 Tesak) equipped with the host computer PDP 11 Digital, in order to enhance the contrast of the labeling. A very high density of NPY receptors is present in the limbic regions (hippocampus, amygdaloid complex, septal nuclei), in the cortex, and in some thalamic nuclei, while in some hypothalamic regions (paraventricular nucleus and median eminence) we detected a lower amount of NPY receptors. At the mesencephalic level, the substantia nigra presents a very high density of NPY receptors.

Detection of vasopressin messenger RNA in cells within the bed nucleus of the stria terminalis by in situ hybridization histochemistry

In situ hybridization histochemistry and quantitative autoradiography were used to confirm the presence of cells within the bed nucleus of the stria terminalis (BNST) which express the vasopressin (VP) gene and to assess the biosynthetic capacity of these cells throughout the rostrocaudal extent of the nucleus. Brain sections from adult male Wistar rats were hybridized with a 35S-labeled 48-base oligonucleotide probe. Clusters of grains were present over cells in the BNST. Cells were parvocellular in appearance and signal over cells was determined to be specific since it was abolished by RNase pretreatment or incubation with 100-fold excess unlabeled probe. The distribution of VP-mRNA containing cells in the BNST corresponds closely to that previously reported by immunocytochemistry. No clear-cut rostral to caudal gradient was found for gene expression as measured by grains/cell. In situ hybridization techniques can provide a powerful tool to study the regulation of central VP pathways in the BNST.

GABA concentrations in forebrain areas of suicide victims

Concentrations of GABA and seven other amino acids, including the neurotransmitters or neuromodulators taurine, glycine, aspartate, and glutamate, were determined in postmortem brain samples from suicide victims and normal controls. The five brain areas (caudate nucleus, nucleus accumbens, frontal cortex, amygdala, and hypothalamus) contained very similar concentrations of the amino acids in both groups. The only significant difference between the groups was a low glutamine concentration in the hypothalamus of suicide victims. Even when the data were adjusted for differences in tryptophan concentration, a putative biochemical index for agonal and postmortem changes of brain tissue, no new differences emerged in the concentrations of neuroactive amino acids between suicide victims and control subjects.

17 beta Estradiol-induced increase in brain dopamine D-2 receptor: antagonism by MIF-1

Animal behavioral and neurochemical studies implicate dopaminergic systems in the neurological sequelae induced by estrogen. In the present study, we demonstrated for the first time that MIF-1, a neuropeptide unrelated to classical dopamine agonists, when given prior to, concurrently with, and after 17 beta-estradiol, antagonized significantly the estrogen-induced increase in the density of dopamine D-2 receptor both in the striatum and the mesolimbic area of male rat brain. The current findings have implications for the prophylactic and therapeutic potential for MIF-1 in extrapyramidal motor disorders caused by estrogen imbalance in humans.

Effects of methamphetamine administration on brain neurotensin-like immunoreactivity in rats

The effects of methamphetamine (MAP) administration on neurotensin-like immunoreactivity (NTLI) were investigated in the rat brain. A single administration of MAP induced dose-dependent and reversible increases in NTLI in the caudate-putamen, limbic forebrain and midbrain. NTLI in the caudate-putamen, limbic forebrain and midbrain was also enhanced after repeated administration of MAP. It was assumed that MAP enhanced NTLI in the caudate-putamem, limbic forebrain and midbrain through its action upon the nigrostriatal and mesolimbic dopamine systems.

Distribution and morphology of vasopressin-, neurophysin II-, and oxytocin-immunoreactive cell bodies in the forebrain of the cat

Experiments were done to provide a detailed map of the location and a description of morphological characteristics of vasopressin (AVP-IR)-, neurophysin II (NII-IR)- and oxytocin (OXY-IR)-immunoreactive neuronal perikarya in the forebrain of the cat. In addition, the location of cells in the forebrain retrogradely labeled following injections of tracers into the neurohypophysis was determined. The distribution of AVP-IR and NII-IR was similar in all cases studied. Most of the cells containing AVP-IR and OXY-IR were observed in the hypothalamic paraventricular (PVH) and supraoptic (SON) nuclei. In addition, AVP-IR and OXY-IR cell bodies were found in the regions of the nucleus of the diagonal band of Broca, the dorsal chiasmatic nucleus, the anterior hypothalamic-preoptic area, the periventricular area, the nucleus circularis, the perifornical area of the lateral hypothalamus, the accessory SON, the area of the tuber cinereum (Tca), and the medial nucleus of the amygdala. The density of AVP-IR cells was greater than that of OXY-IR cells in these regions. Several forebrain areas were also observed to contain only AVP-IR perikarya: the suprachiasmatic nucleus (Sc), the bed nucleus of the stria terminalis, and the region of the substantia innominata and ventral globus pallidus (SI/GP). In addition, the dorsomedial nucleus of the hypothalamus only contained OXY-IR perikarya. Most of the cells immunoreactive to AVP were multipolar and had spinelike processes over their somata and proximal dendrites. In addition, the majority of cells in the PVH and SON were round or oval, whereas those outside these nuclei were fusiform or triangular. The mean somal area of AVP-IR cells in the region of the SI/GP was significantly (P less than 0.05) larger than that of AVP-IR cells in all other regions examined, whereas the mean somal area of Sc AVP-IR cells was significantly (P less than 0.05) smaller than that of all other groups of AVP-IR cells examined. Most OXY-IR cells were similar morphologically to those immunoreactive to AVP, except that OXY-IR cell bodies and their appendages did not have spinelike processes. In addition, OXY-IR perikarya were generally of uniform size. OXY-IR cells in the PVH and accessory SON were significantly (P less than 0.05) larger than AVP-IR cells in the same regions, but were not different from AVP-IR cells in the lateral hypothalamus and SON.(ABSTRACT TRUNCATED AT 400 WORDS)

Hydrocortisone administration alters glial reaction to entorhinal lesion in the rat dentate gyrus

Young adult male rats received subcutaneous implants of Alzet osmotic minipumps which delivered 400 micrograms hydrocortisone per day. Untreated rats received no pumps or pumps containing the vehicle. Five days after receiving the implantation, both groups of rats were subjected to unilateral entorhinal lesion. Seven days after surgery, brains were analyzed quantitatively for glial changes in the denervated dentate outer molecular layer. Numerical densities of astrocytes and nonastrocytic glia were calculated by cell counting using 1.0-micron toluidine blue-stained sections. Glial acid phosphatase staining was quantitated using computer-assisted cytophotometric measurement of individual glial cells. Hydrocortisone-treated animals demonstrated 31% more astrocytes and 22.4% less nonastrocytes in the dentate outer molecular layer compared with untreated animals. Glia in the treated animals also showed a 33% decrease in average optical density of cytoplasmic acid phosphatase staining. These findings suggest that hydrocortisone treatment prior to and following an entorhinal lesion accelerates lesion-induced migration of astrocytes to the outer molecular layer, and reduces the increase in microglial number resulting from the lesion. The observed effect on microglia may result from a direct hormonal inhibition of local proliferation of microglia or from the well known systemic anti-inflammatory action of glucocorticoids on monocytes, the putative precursors of brain microglia. Our findings suggest that glucocorticoid hormones significantly alter the response of non-neuronal cells to neural tissue damage.

Effects of short-term lithium administration on tryptophan levels and 5-hydroxytryptamine synthesis in whole brain and brain regions in rats

The effects of short-term lithium administration on tryptophan levels and 5-hydroxytryptamine (5-HT) synthesis in whole brain and brain regions in rats were studied. Short-term lithium administration was found to increase whole brain tryptophan levels without affecting whole brain 5-HT synthesis. However, the increase of tryptophan varied between various brain regions, which may possibly be due to differences in the synaptosomal uptake of tryptophan between brain regions. In the striatum, where the tryptophan increase was most pronounced, an increase in 5-HT synthesis was found too. These latter findings suggest that the increase in 5-HT synthesis might be due to an increase in tryptophan availability.

Distribution of putrescine in rat brain measured by gas chromatography-mass spectrometry

We measured putrescine levels in minute sites of single rat brains using a sensitive, specific assay involving gas chromatography-mass spectrometry. The putrescine level was measured in 20 sites of single rat brains: three sites in the cerebral cortex, six sites in the hypothalamus, three sites in the basal ganglia, three sites in the thalamus, three sites in the limbic system, and two sites in the cerebellum. The level of putrescine was very high in the hypothalamus, high in the basal ganglia and limbic system, and low in the thalamus, cerebellum, and two of the three sites in the cerebral cortex. The highest levels were in the anterior hypothalamic area and the lateral hypothalamic area, and the lowest levels were in the vermis and the lobe of the cerebellum.

The measurement of neuropeptide Y in discrete hypothalamic and limbic regions of male rhesus macaques with a human NPY-directed antiserum

The distribution of neuropeptide Y (NPY) in microdissected brain regions of male macaques was quantified with a specific radioimmunoassay (RIA). The RIA consisted of a specific antiserum (R31) against human NPY that could detect 7 pg/tube with an IC50 of 125 pg/tube at a final dilution of 1:20,000. Varying amounts of rabbit and monkey mediobasal hypothalami yielded parallel [125I]NPY displacement curves in the assay and similar chromatographic elution profiles with those of synthetic human NPY. The NPY activity in acid extracts of discrete brain regions in castrate and castrated-testosterone-treated rhesus males was highest in mediobasal hypothalamus, followed by more rostral hypothalamic regions and amygdaloid nuclei. Testosterone did not alter NPY levels in any of the brain areas that we examined.

Quantitative autoradiography of multiple 5-HT1 receptor subtypes in the brain of control or 5,7-dihydroxytryptamine-treated rats

The distribution of the 2 main types (A and B) of 5-HT1 binding sites in the rat brain was studied by light-microscopic quantitative autoradiography. The 5-HT1A sites were identified using 3H-8-hydroxy-2-(N-dipropylamino)tetralin (3H-8-OH-DPAT) or 3H-5-HT as the ligand. In the latter case, it was shown that 3H-5-HT binding to 5-HT1A sites corresponded to that displaceable by 0.1 microM 8-OH-DPAT or 1 microM spiperone. The "non-5-HT1A" sites labeled by 3H-5-HT in the presence of 0.1 microM 8-OH-DPAT corresponded mainly to 5-HT1B sites. 5-HT1A binding was notably high in limbic regions (dentate gyrus, CA1 and CA3 hippocampal regions, lateral septum, frontal cortex), whereas 5-HT1B binding was particularly concentrated in extrapyramidal areas (caudate nucleus, globus pallidus, substantia nigra). Except in the latter regions, where only one class of 5-HT1 sites was found, both 5-HT1A and 5-HT1B sites existed in all areas examined. The selective degeneration of serotoninergic neurons produced by an intracerebral injection of 5,7-dihydroxytryptamine was associated only with a significant loss of 5-HT1A binding to the dorsal raphe nucleus (-60%) and of 5-HT1B binding to the substantia nigra (-37%). These results are discussed in relation to the possible identity of 5-HT1A and/or 5-HT1B sites with the presynaptic 5-HT autoreceptors controlling nerve impulse flow and neurotransmitter release in serotoninergic neurons.

The distribution of dopamine immunoreactivity in the forebrain and midbrain of the lizard Gekko gecko: an immunohistochemical study with antibodies against dopamine

The distribution of dopamine (DA) immunoreactivity in the forebrain and the midbrain of the lizard Gekko gecko was studied by using recently developed antibodies against DA. Dopamine-containing cells were found around the glomeruli of the olfactory bulb, in several parts of the periventricular hypothalamic nucleus, in the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus of the diencephalon, and in the ventral tegmental area, the substantia nigra, and the presumed reptilian equivalent of the mammalian A8 cell group of the mesencephalon. Dopaminergic fibers and terminals were observed throughout the whole brain, but particularly in the diencephalon and the telencephalon. The nucleus accumbens appears to have the most dense innervation, but also the striatum, amygdaloid complex, olfactory tubercle, septum, and dorsal ventricular ridge (especially its superficial zone) show numerous DA-containing fibers and terminals. Except for the lateral cortex, cortical areas are not densely innervated by DA fibers. In several respects DA distribution in the gekkonid brain differs from that in other reptiles studied. For instance, in the Gekko the dorsal ventricular ridge is densely innervated by DA fibers, whereas in turtles and crocodiles the same structure shows only weak catecholaminergic histofluorescence. When compared to the distribution of DA immunoreactivity in mammals, it appears that the DA system in the gekkonid telencephalon resembles the distribution of DA in the limbic forebrain and striatum of mammals. Whether these similarities in distribution of DA also imply similarities in function will be discussed.

Widespread reduction of somatostatin-like immunoreactivity in the cerebral cortex in Alzheimer's disease

Although several studies have documented reduced concentrations of somatostatin-like immunoreactivity (SLI) in the cerebral cortex in Alzheimer's disease, there is controversy concerning the extent and importance of these changes. We measured SLI in brains obtained post mortem from 12 patients with pathologically confirmed Alzheimer's disease and from 13 neurologically normal controls. All major cortical and subcortical regions were examined. Widespread reductions of SLI in Alzheimer's disease cerebral cortex were found, with the most profound changes seen in temporal lobe; but there also were major reductions in both the frontal and occipital cortex. There were no significant reductions in subcortical regions. Characterization of SLI by high-pressure liquid chromatography showed no significant difference in profiles between Alzheimer's disease and control frontal cortex. These results suggest that the reduction in somatostatin immunoreactivity in Alzheimer's disease may be caused by degeneration of intrinsic somatostatin cortical neurons.

A comparison of regional somatostatin and neuropeptide Y distribution in rat striatum and brain

Somatostatin-like immunoreactivity (SLI) and neuropeptide Y-like immunoreactivity (NPYLI) were detected using specific radioimmunoassays in extracts from rat brain. Since we have previously found a topographic distribution of SLI in rat striatum the distribution of NPYLI was examined in the same regions. NPYLI showed an identical distribution to SLI in rat striatum and levels were significantly correlated (r = 0.93, P less than 0.01). Concentrations of both neuropeptides were consistently highest in ventromedial striatum and nucleus accumbens while they were lowest in dorsolateral striatum. These findings provide further evidence of neurochemical heterogeneity in the striatum. Concentrations of NPYLI and SLI were also significantly correlated in cerebral cortex (r = 0.99, P less than 0.01). Concentrations of NPYLI were generally higher than SLI and showed a similar predilection for limbic system nuclei. The present findings support the concept that somatostatin and neuropeptide Y may be co-localized in both striatal and cortical neurons.

Differential distribution of neurotransmitter amino acids from the limbic system of aggressive and non-aggressive bull strains

The amino acid content of crude synaptosomal fractions from the limbic system and related CNS regions showed significant differences between the aggressive Spanish fighting-bull and the non-aggressive Friesan bull breeds. Neurotransmitter amino acids (glutamate, aspartate, GABA and glycine) were the most unequally distributed. A higher ratio of excitatory to inhibitory neurotransmitter amino acids was always found in all the CNS regions studied in the aggressive breed. The concentrations of five non-transmitter amino acids (threonine, alanine, serine, leucine and isoleucine) showed minor variations between both studied bull strains and cannot be ascribed to differences in central energy metabolism. The results are explained in terms of a possible relationship between the amino acid neurotransmitter levels and the innate aggressiveness of the Spanish fighting-bull.

Sexual dimorphism of messenger RNA isolated from neonatal rat brain

The rat brain is sexually dimorphic with respect to structure and function, and there is evidence that these differences are effected in the fetus through changes in protein synthesis, some of which may result from the intervention of gonadal steroids. To investigate this, messenger RNA (mRNA) from the limbic system and cerebellum of neonatal rats was prepared, translated in a rabbit reticulocyte system in vitro and the products were analysed by two-dimensional electrophoresis and fluorography. Some of the results were further analysed using image analysis. There was a striking sexual dimorphism in the patterns of incorporation of [35S]methionine into proteins using mRNA from the limbic system, in that groups of proteins were apparently present in male-but not in female-derived fluorograms and vice versa. One protein, tentatively identified from its coordinates as alpha-tubulin, was more abundant in male-derived fluorograms. Although there were no clear-cut qualitative sex differences using mRNA derived from the cerebellum, that derived from the male cerebellum appeared to be consistently more active. These results provide direct evidence for a sexual dimorphism at the transcriptional level in the neonatal limbic system of the rat.

Brain dopamine D-1 receptors in senile dementia

Brain dopamine D-1 binding sites were studied by using [3H]flupenthixol in 4 brain regions of 44 senile patients with neuropathologically verified organic dementia and 28 age-matched controls. The D-1 binding sites were decreased in the substantia nigra and nucleus accumbens in patients with Alzheimer's disease, while no change was found in multi-infarct or combined dementia. The striatal D-1 binding sites were unchanged in all groups of patients. Only a few correlations between various clinical and post-mortem variables and the [3H]flupenthixol binding of the dementia patients were found. The findings of this study indicate that there is reduction of brain D-1 binding sites in patients with Alzheimer's disease.

Muscarinic cholinergic receptors and the canine model of narcolepsy

The role of the muscarinic cholinergic receptor in narcolepsy was examined using radioligand binding to various brain regions of normal and genetically narcoleptic Doberman pinschers. In this multi-litter study, a previous report of a proliferation of muscarinic cholinergic receptors in the brainstem was confirmed, and the concentration of the M2 receptor subtype, in particular, was elevated. This up-regulation of brainstem cholinergic receptors suggests a problem with release of acetylcholine, which, together with previous reports of an impairment of dopamine release, may be indicative of a fundamental membrane problem in narcolepsy.

Norepinephrine and amino acids in prepyriform cortex of rats fed imbalanced amino acid diets

Monoamines and amino acids were measured in anterior prepyriform cortex (PPC) and anterior cingulate cortex (CC) of male Sprague-Dawley rats after they were offered basal, imbalanced (IMB) or corrected amino acid diets, limited in threonine (THR) or isoleucine (ILE). In the THR study, brains were taken after 2.5 hr of feeding, when intake of THR-IMB was just depressed. In the ILE study the brains were taken after 3.5 hr on ILE-IMB, a less severely imbalanced ration, before the onset of food intake depression. The PPC has been shown to be involved in the acute response of animals to imbalanced amino acid diets. In the PPC from the IMB diet groups, NE was reduced by 30%, but the other monoamines were unchanged. In CC, an area involved in the adaptive, but not the acute feeding response to imbalanced diets, the monoamines were unchanged in the IMB diet groups. In both studies, in both tissues, the limiting amino acids were decreased in the IMB groups, although the decrease of ILE in the CC failed to reach significance. The remaining indispensable amino acids, added to create the imbalance, were slightly reduced in the THR-IMB group, but not in the ILE-IMB group in both tissues. Thus, the amino acid patterns were altered in the PPC and CC, as they are in whole brains from animals fed imbalanced amino acid diets. These results also suggest that the concentration of NE in the PPC may be associated with the initial food intake response of animals to imbalanced amino acid diets.

Lateralized decrease in self-stimulation induced by haloperidol in rats with unilateral 6-hydroxydopamine lesions

Rats with bilateral hypothalamic electrode placements which generated similar self-stimulation rate-intensity functions were subjected to unilateral injections of 6-hydroxydopamine (6-OHDA) into A9 and A10 areas. Following 12 weeks of postoperative recovery which was bilaterally symmetrical the rats were administered 0.1 mg/kg haloperidol. In sham- and vehicle-injected control rats the haloperidol produced bilaterally symmetrical decreases in self-stimulation. In the rats with 6-OHDA lesions the haloperidol effect was asymmetric with a much greater decrease in self-stimulation evident for electrode placements in the dopamine deficient hemisphere than for electrodes in the non-lesion hemisphere. Biochemical evaluation of the lesions indicated that dopamine was severely depleted in limbic and striatal forebrain areas. The combined use of a lesion with a pharmacological blockade of a neurotransmitter system appears to be an effective technique to distinguish reward versus performance effects of the transmitter on self-stimulation.

Nuclear and cytosolic androgen receptor levels in the limbic brain of neonatal male and female rats

Nuclear and cytosolic androgen receptors in the limbic brain were measured in neonatal male and female rat pups. There were no sex differences in cytosolic receptor concentrations during the neonatal period in any of the regions studied (hypothalamus, amygdala, preoptic area and septum). Receptor concentrations in all 4 regions increase gradually over the first 10 days of life, with no change in the affinity for 5-alpha-dihydrotestosterone. Nuclear receptor levels in intact pups, measured using an exchange assay, are highest between days 4 and 8 of life. In general, nuclear receptor levels are higher in males than in females; however, this sex difference is most consistently seen in the amygdala. These results are discussed in relation to sex differences in circulating testosterone levels and with respect to the contribution of androgens to the sexual differentiation of behavior.

Regional brain levels of N-acetyl-aspartyl-glutamate: the effect of kindled seizures

Rats were subjected to daily amygdaloid-kindling stimulation and sacrificed 48 h after their fifth stage-5 kindled seizure. Regional brain dissection was performed and the regions assayed for levels of N-acetyl-aspartyl-glutamate, an endogenous dipeptide specific to the brain and a putative excitatory neurotransmitter. Kindling produced significant increases in this dipeptide in the entorhinal cortex.

Regional distribution of the dopamine D2 receptors in the mesotelencephalic dopamine neuron system of human brain

Using the [3H]spiroperidol binding technique, we performed a regional distribution of the D2 receptors in the human mesotelencephalic dopamine neuron system. D2 receptors were found in decreasing order of concentration in caudate nucleus greater than putamen greater than nucleus accumbens greater than globus pallidus greater than amygdala greater than substantia nigra. D2 receptors could not be detected in any cortical region. The nigrostriatal and mesolimbic components of the mesotelencephalic dopamine neuron system are easily to reconstitute. If there exists a mesocortical component in man, its actions appear not to be mediated by D2 receptors.

Regulation of rat brain angiotensin II (AII) receptors by intravenous AII and low dietary Na+

Previous studies have shown the presence of specific AII receptors at several areas of the brain. The purpose of this study was to examine by radioreceptor assay the effect of intravenous AII infusion (5 or 25 ng/kg/min) and low dietary Na+ (less than 8 mmol/100 g) on AII receptors in five brain regions: the olfactory lobes (OLF), hypothalamus/thalamus/septum (HTS), midbrain (MID), cerebellum (CER) and medulla (MED). Scatchard analysis of binding data from control rats showed significant (P less than 0.01 ANOVA) differences between brain areas in both Ka (1.54 OLF, 1.87 HTS, 1.25 MID, 1.33 MED, 0.77 CER x 10(9) M-1) and Ro (321 OLF, 224 HTS, 203 MID, 145 MED, 41 CER fmol/g tissue). Following the i.v. infusion of AII for 4-7 days, marked changes were observed in the areas with a porous BBB, the HTS and MED. Both the Ka [3.20 (HTS) and 0.67 (MED) x 10(9) M-1] and Ro [116 (HTS) and 249 (MED) fmol/g tissue] changed. In addition, decreases in Ro were also observed in the OLF (241 fmol/g tissue) and CER (21 fmol/g tissue), areas which have not been considered as being accessible to blood-borne AII. A low Na+ diet for 21-30 days changed the Ka and Ro in all five regions but not in similar directions. Furthermore, with the exception of the OLF the direction of change was not similar to that caused by i.v. infusion of AII. It was concluded that AII receptor sites in the rat brain differ from each other in both receptor properties in their response to such regulatory factors as AII Na+ depletion.(ABSTRACT TRUNCATED AT 250 WORDS)

[Changes in the level of serotonin in the brain and immunocompetent organs during the formation of the immune response]

The serotonin content increased in adrenals within 20 min after immunization of rats with sheep red blood cells, and diminished in ventral part of the anterior hypothalamus, hippocampus and in thymus. The number of antigen--responsive cells was increased twofold in bone marrow after the 1000-fold increase of the antigen dose. On the 4-5th days, the dependence of antibody-forming cells and rosette-forming cells number on the antigen dose was still observed in the spleen. The correlation between the serotonin level in the above brain structures and immunocompetent organs and the intensity of immune responses is discussed.

Various types of thyrotropin-releasing hormone receptors in discrete brain regions and the pituitary of the rat

Receptors for thyrotropin-releasing hormone (TRH) in the rat brain and the pituitary are heterogenous. The receptors were classified into four types according to the dissociation constant (KD). High-affinity receptors (KD less than 3 nM) are present in the pituitary, hypothalamus, amygdala, and limbic forebrain which contains the nucleus accumbens and the septum. Intermediate-affinity receptors (KD, 5-16 nM) are evidently present in the frontal cortex, hippocampus, striatum, thalamus, and the brainstem, but may also be present in other regions. Low-affinity TRH receptors (KD, 50-80 nM) are seen in the limbic forebrain, amygdala, and the hypothalamus. Very-low-affinity receptors (KD, 215 nM) exist in the pituitary. Experiments using DN-1417 (gamma-butyrolactone-gamma-carbonyl-histidyl-prolinamide citrate), a synthetic TRH analogue with a more potent central activity, indicated the presence of TRH receptors having a high affinity to DN-1417 at least in the limbic forebrain but not in the pituitary. This type of receptor is not labeled by [3H](3-methyl-histidine2)-TRH. Density of the TRH receptor is the highest in the pituitary and next highest in the amygdala.

The neurotoxic actions of 1-methyl-4-phenylpyridine (MPP+) are not prevented by deprenyl treatment

1-Methyl-4-phenylpyridine (MPP+) injected into the cerebral ventricles (ICV) of mouse caused depletions of striatal dopamine (DA)(-42%), 3,4-dihydroxyphenylacetic acid (DOPAC) (-34%) and homovanillic acid (HVA) (-16%) content without significant reductions in levels of noradrenaline (NA), serotonin (5-HT) or 5-hydroxyindoleacetic acid (5-HIAA). When deprenyl was administered before MPP+, striatal DA and its metabolites were further depleted, and striatal NA and 5-HT levels also were reduced. Further, whilst ICV MPP+ alone failed to influence the biochemistry of the limbic areas (nucleus accumbens plus tuberculum olfactorium), in the presence of deprenyl MPP+ caused 20-40% reductions in levels of limbic NA, DA, DOPAC, HVA, 5-HT and 5-HIAA. Therefore, deprenyl treatment does not prevent the neurotoxic actions of MPP+; indeed, a more extensive neurotoxicity for MPP+ is revealed in the presence of this monoamine oxidase inhibitor.

Brain muscarinic receptors in senile dementia

Muscarinic receptors were analyzed in various post-mortem brain samples of 39 patients with different types of dementia and of 30 age-matched controls by the specific binding of [3H]QNB. The diagnoses were verified neuropathologically. The binding of [3H]QNB was significantly decreased in the hippocampus, amygdala and nucleus accumbens in patients with Alzheimer's disease (AD) and with combined type of dementia (CD), whereas in patients with multi-infarct dementia (MID) the binding was not significantly decreased in the limbic areas but only in the caudate nucleus. Of the clinical variables, orofacial dyskinesias in patients with AD but not with MID correlated with low brain weight and with the decreased [3H]QNB binding in the striatum and frontal cortex. The results reveal some differences between AD and MID. Changes in muscarinic receptor binding show that the cholinergic neurons in the limbic system are especially vulnerable in patients with AD and CD.

Biogenic amine alterations in limbic brain regions of muricidal rats

Endogenous levels of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), dopamine, 3-4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in eight brain regions of muricidal (mouse killing) and non-muricidal rats. The regions studied were: the frontal cortex, caudate nucleus, septal area, hypothalamus, thalamus, amygdalae with pyriform cortex, anterior hippocampal formation, and brain stem. Serotonergic systems showed significant differences in discrete brain regions of muricidal rats as compared to those of non-muricidal rats. The differences were: significantly higher serotonin levels in the amygdalae and significantly higher 5-HIAA levels in the hippocampus of the muricidal rats. Serotonin levels were also higher in the hypothalamus of the muricidal rats, but the difference reached only borderline significance. Dopaminergic systems also showed significant differences in the septum of muricidal rats, where DOPAC levels were significantly lower than those of non-muricidal rats. The hippocampus of muricidal rats showed significantly higher dopamine levels. HVA levels in the hippocampus of muricidal rats were also higher but reached only borderline significance. These data suggest both central serotonergic and central dopaminergic involvements in rat muricidal behavior. The discrete brain regions which showed differences further suggest a limbic involvement.

An electrochemical approach to sleep metabolism: a pO2 paradoxical sleep system

Oxygen cathodes chronically implanted in the cat brain recorded changes of local oxygen concentration during paradoxical sleep. Phasic high amplitude pO2 changes were consistently observed in some regions and were characterized by a dramatic increase in the amplitude of the oscillations. The regions displaying these responses included part of the reticular formation, hypothalamus, amygdala and cerebellum which we refer to as the "pO2 paradoxical sleep system." This pO2 pattern was not observed in white matter, in the neocortex or in specific thalamic nuclei. It is postulated that the phasic response is due to a local increase of neuronal activity requiring increased oxygen availability and augmented protein synthesis during paradoxical sleep and may form part of a system related to "plastic" phenomena.

The development of the glucocorticoid receptor system in the rat limbic brain. I. Ontogeny and autoregulation

In order to characterize the development of the glucocorticoid receptor system in the brain, we examined [3H]dexamethasone binding in rat pups at various ages. Using an in vitro, cytosol, receptor assay we found evidence for low levels of glucocorticoid receptors perinatally with a subsequent increase in receptor concentrations that began by about the end of the first week of life. We have also shown that receptors during this period have a ligand specificity similar to that of receptors in adult animals. The postnatal increase in receptor levels parallels an increase in circulating corticosterone titers. Thus, receptor and hormone levels increase coincidentally. In adult animals, however, increasing levels of corticosterone are associated with a decrease in receptor levels and vice versa, such that corticosterone is thought to regulate its own receptor (i.e. autoregulation). This suggested an absence of autoregulation during development. We then determined hippocampal receptor concentrations of rats treated for 5 days with corticosterone, or adrenalectomized (ADX) 5 days prior to assay, examining whether up- or down-regulation occurs throughout development. In adults corticosterone treatment decreased (-45%) and long-term adrenalectomy increased (211%) glucocorticoid receptor concentrations. In contrast, at the youngest age tested (Day 10), the effects of manipulations of corticosterone titers on receptor concentrations were negligible. The potential for autoregulation emerged gradually throughout development. Thus, it appears that corticosterone regulation of its own receptors emerges only by about the time of puberty, and that this permits an increase in receptor levels to occur despite the concurrently increasing levels of circulating corticosterone.

Effects of neuroleptic drugs on brain beta-endorphin immunoreactivity

The effect of chronic haloperidol on brain beta-endorphin immunoreactivity was examined in rats. Chronic haloperidol resulted in significant reductions of beta-endorphin immunoreactivity within the striatum, but other brain regions were uneffected. When a variety of neuroleptic drugs were tested, fluphenazine, chlorpromazine and haloperidol resulted in comparable reductions in beta-endorphin immunoreactivity in the striatum. These findings suggest a functional interaction between beta-endorphin and dopamine systems in the striatum.

Distribution of corticotropin-releasing factor in rat brain

Corticotropin-releasing factor (CRF) has been measured in 70 brain nuclei and in the posterior pituitary of the rat by radioimmunoassay (RIA) developed against synthetic rat CRF. CRF-like immunoreactivity was detected in 32 brain areas in concentrations higher than 0.3 ng/mg protein. Most of the CRF in the brain was in the hypothalamus, where the highest level was found in the median eminence. Several limbic nuclei, such as the lateral septal nucleus, central amygdaloid nucleus, periventricular thalamic nuclei, and bed nucleus of the stria terminalis, contained CRF in moderate to low concentrations. CRF was detected in a number of lower brain-stem nuclei, including the ventral tegmental area, central gray matter, dorsal raphe, parabrachial nuclei, and locus ceruleus. Surprisingly, the highest extrahypothalamic CRF level was found in the inferior olive. Our RIA data are, in general, fairly consistent with immunohistochemical findings.

Effect of systemically administered caerulein on dopamine metabolism in rat brain

The effect of caerulein, a cholecystokinin-like peptide, on the dopamine (DA) system was examined in rat brain. Caerulein, when tested in vitro, had no significant influence on either D-1 or D-2 DA receptors. A single injection of caerulein (400 micrograms/kg, i.p.) reduced both homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the striatum. No significant change in DA metabolites was found in the other 7 areas (polar and medial fields of prefrontal cortex, anterior cingulate cortex, nucleus accumbens, tuberculum olfactorium, septum and amygdala). After repeated injections of caerulein (200 micrograms/kg, i.p., daily for 5 days), the decreases in striatal HVA and DOPAC had disappeared, while the amount of HVA had increased in the nucleus accumbens. These results suggest that peripherally administered caerulein modulates the nigrostriatal and mesolimbic DA neuron systems in the different modes of action.

[Homovanillic acid levels in corpus striatum, limbic system and diencephalon of male and female rats]

The HVA levels in corpus striatum, limbic system and diencephalon in male and female rats during the postnatal period have been measured. The HVA levels in corpus striatum and diencephalon differed significantly when both sexes wee compared, whereas in limbic system significant differences were not found. A decrease in the levels of HVA in all areas studied was observed.

Serotonin and 5-hydroxyindoleacetic acid concentrations in individual hypothalamic nuclei and other brain areas of rat

Serotonin and 5-hydroxyindoleacetic acid (5-HIAA) were measured in individual nuclei of rat hypothalamus and other brain areas using HPLC with electrochemical detection. 5-HIAA levels were first demonstrated in hypothalamic and some discrete brain areas. The 5-HIAA/5-HT ratio was highest in the n. caudatus putamen, high in the n. ventromedialis and lowest in the n. suprachiasmaticus.

Postmortem studies in psychiatry

Neurochemical postmortem examination of brain tissue may never be completely replaced as a research tool in psychiatry. This method has already provided support for the hypotheses relating norepinephrine, dopamine, serotonin, peptides, and hemisphere asymmetries to psychiatric syndromes.

L-Dopa methyl ester--a candidate for chronic systemic delivery of L-Dopa in Parkinson's disease

Continuous intravenous infusions of L-Dopa as a treatment for response swings in Parkinson's disease are limited by the insolubility and acidity of L-Dopa. Its methyl ester is a soluble neutral derivative that might be of benefit to these patients, and is examined in the present study in behavioural and biochemical animal models. On intraperitoneal or subcutaneous administration to mice L-Dopa methyl ester was equivalent to L-Dopa in reversing reserpine-induced akinesia and producing contraversive circling behaviour in rats with a 6-hydroxydopamine lesion of the medial forebrain bundle. On oral administration the methyl ester was more active. The administration of L-Dopa or the methyl ester produced equivalent changes in striatal and mesolimbic dopamine, homovanillic acid, and 3,4-dihydroxyphenylacetic acid metabolite levels. We suggest that systemic or subcutaneous infusion of L-Dopa methyl ester to patients who experience response fluctuations may provide a means of maintaining mobility.

Differential changes in central serotonin and dopamine receptors in spontaneous hypertensive rats

Functional significance of central dopaminergic and serotonergic mechanism in relation to the pathogenesis of hypertension, was assessed in the brain of hypertensive rat (SHR) models. In the mesolimbic area, dopamine receptors were found to be significantly enhanced in the SHR as compared with the normotensive control, whereas serotonin receptors in the hippocampus and frontal cortex were not significantly altered in the SHR. Our results, coupled with our previous finding on the enhanced 3H-spiroperidol binding in the striatum support the hypothesis that supersensitivity of central dopamine receptors may contribute towards the development of hypertension.

Effect of gonadectomy on brain homovanillic acid levels

The effect produced by gonadectomy on homovanillic acid (HVA) levels in three regions of male and female rat brain during the postnatal period has been studied. In all areas, the HVA levels rise in gonadectomized rats when they are compared with the controls in the first period, but later these levels decrease with respect to the control rats. When female rats were 60 days old there were differences between gonadectomized and controls; these differences were not found in male rats.

Corticotropin releasing factor (CRF) immunoreactivity in hypothalamic and extrahypothalamic nuclei of sheep brain

In sheep, 26 brain areas of 62 investigated contained corticotropin releasing factor (CRF)-like immunoreactivity in concentrations higher than 0.5 ng CRF/mg protein. Most of the CRF in the brain was in the hypothalamus. The highest level of CRF in the sheep brain was in the median eminence, almost two orders of magnitude higher than anywhere else. All of the hypothalamic nuclei had measureable amounts of CRF. A number of extrahypothalamic regions such as amygdala, hippocampus, claustrum, cingulate cortex, habenula and certain lower brainstem nuclei had CRF but generally in very low concentrations.

Hypothalamic and limbic GABA concentrations and turnover rates and glutamate concentrations following induction of hyperprolactinemia in ovariectomized rats

Hyperprolactinemia was induced by transplantation of pituitaries of donor rats under the kidney capsule of ovariectomized recipient rats. This results in a permanently increased serum prolactin and temporarily suppressed luteinizing hormone (LH) levels. Concentrations of gamma-aminobutyric acid (GABA) and glutamate as well as turnover rates of GABA were determined in micropunches of the nucleus accumbens (ACB), medial preoptic area (MPO), anterior and posterior part of the mediobasal hypothalamus (AMBH and PMBH) and in the mediocortical amygdala (AMY). GABA concentration in the ACB and MPO were reduced in hyperprolactinemic rats. This was significant at day 8. At days 4 to 21 following pituitary transplantation glutamate concentrations were also significantly reduced in the AMY. The most conspicuous changes in GABA turnover rates were observed in the ACB and MPO. In the former structure hyperprolactinemia reduced GABA turnover, while in the latter high prolactin levels increased GABA turnover at day 4. It is concluded that the suppressive effect of hyperprolactinemia on blood LH levels may involve a preoptic GABAergic component and possibly a glutamatergic mechanism in the AMY. Alternatively, the AMY and the ACB may be involved in eliciting the many behavioral effects associated with hyperprolactinemia.

[Effect of cholecystokinin octapeptide on brain monoamine levels during feeding and drinking motivational excitation]

The paper presents studies of the influence of octapeptide cholecystokinin (ChCK-8) on the level of dofamine, noradrenaline and serotonine in the hypothalamus, septum, amygdala, striatum and mesencephalon of the rats brain during 24-, 48- and 96-hour alimentary and water deprivation. A change of catecholamines content under the influence of ChCK-8 was observed for the most part in conditions of thirst and only in the hypothalamus. ChCK-8 action in conditions of water deprivation was selective and directed mainly to the restoration of the changes in transmitter's level. ChCK-8 did not have a significant influence on the level of the brain monoamines during hunger. It may be assumed, that "satiation" hormone ChCK-8 is to a great extent connected with the mechanisms of reinforcement, and its "satiating" effect would appear at catecholamines' level in the process of satisfying of corresponding need.

Changes in hypothalamic and extra-hypothalamic vasopressin content of water-deprived rats

A correlative radioimmunoassay (RIA) and immunocytochemical (ICC) study was carried out on vasopressin (VP) distribution and content in brains of normal and 3-day water-deprived rats. By RIA there were statistically significant differences in brain VP per pg/mg between normal and osmotically stressed specimens in hypothalamus (338.4 versus 134.4), thalamus (4.8 versus 0.9), septum (18.0 versus 3.4), striatum (1.6 versus 0.7) and amygdala (17.3 versus 1.3), but not in other brain regions measured. Pituitary VP decreased from 71.1 to 8.7 ng/mg, and plasma VP rose from 3.6 to 19.3 pg/ml during water deprivation. Application of the peroxidase-anti-peroxidase ICC method of Sternberger to vibratome sections showed that VP-immunoreactivity in dehydrated specimens decreased in perikarya of paraventricular nucleus and suprachiasmatic nucleus, while intrahypothalamic immunoreactive magnocellular fibers appeared more conspicuous due to proliferation of large Herring bodies. In extrahypothalamic sites VP-immunoreactivity in water-deprived rats was visibly reduced in periventricular thalamus and septum. Thus it is apparent that both intra- and extrahypothalamic VP are affected by osmotic stress, and these results are discussed within the context of current ideas relating to co-activation of neurosecretory cells that project to different sites.

Sustained improvement in tardive dyskinesia with diazepam: indirect evidence for corticolimbic involvement

A rater-bind, ABA's design study of 21 cases indicates that diazepam significantly improves tardive dyskinesia and that some of the improvement persists for an extended period after diazepam is withdrawn. Since benzodiazepine receptors and sites of action seem to be mainly in the neocortex (especially frontal), limbic cortex, and deep limbs nuclei, and these structures provide most of the input into the nigrostriatopallidal system that probably regulates its role in voluntary movement, it may be suggested that impaired corticolimbic control of basal ganglia may be a factor in the pathogenesis of tardive dyskinesia.