Immunohistochemical mapping of galanin-like neurons in the rat central nervous system

Using an antiserum generated in rabbits against synthetic galanin (GA) and the indirect immunofluorescence method, the distribution of GA-like immunoreactive cell bodies and nerve fibers was studied in the rat central nervous system (CNS) and a detailed stereotaxic atlas of GA-like neurons was prepared. GA-like immunoreactivity was widely distributed in the rat CNS. Appreciable numbers of GA-positive cell bodies were observed in the rostral cingulate and medial prefrontal cortex, the nucleus interstitialis striae terminalis, the caudate, medial preoptic, preoptic periventricular, and preoptic suprachiasmatic nuclei, the medial forebrain bundle, the supraoptic, the hypothalamic periventricular, the paraventricular, the arcuate, dorsomedial, perifornical, thalamic periventricular, anterior dorsal and lateral thalamic nuclei, medial and central amygdaloid nuclei, dorsal and ventral premamillary nuclei, at the base of the hypothalamus, in the central gray matter, the hippocampus, the dorsal and caudoventral raphe nuclei, the interpeduncular nucleus, the locus coeruleus, ventral parabrachial, solitarii and commissuralis nuclei, in the A1, C1 and A4 catechaolamine areas, the posterior area postrema and the trigeminal and dorsal root ganglia. Fibers were generally seen where cell bodies were observed. Very dense fiber bundles were noted in the septohypothalamic tract, the preoptic area, in the hypothalamus, the habenula and the thalamic periventricular nucleus, in the ventral hippocampus, parts of the reticular formation, in the locus coeruleus, the dorsal parabrachial area, the nucleus and tract of the spinal trigeminal area and the substantia gelatinosa, the superficial layers of the spinal cord and the posterior lobe of the pituitary. The localization of the GA-like immunoreactivity in the locus coeruleus suggests a partial coexistence with catecholaminergic neurons as well as a possible involvement of the GA-like peptide in a neuroregulatory role.

An apparent genetic polymorphism for a protein present in the hypothalamus of Sprague-Dawley rats

Using two-dimensional gel electrophoresis, an apparent genetic polymorphism was detected in the hypothalamus of a group of inbred Sprague-Dawley rats. The proteins involved in this polymorphism have a molecular weight of 57,000 daltons and isoelectric points ranging from 6.1 to 6.3. These proteins met four criteria that should be met before a positional shift on two-dimension gels can be attributed to a genetic polymorphism. This is the first report of the existence of a genetic polymorphism in the brains of a group of inbred Sprague-Dawley rats. The functional significance of this polymorphism is currently under investigation.

Corticotropin releasing factor-like immunoreactivity in sensory ganglia and capsaicin sensitive neurons of the rat central nervous system: colocalization with other neuropeptides

Immunohistochemistry and radioimmunoassay (RIA) revealed that corticotropin releasing factor (CRF)-like immunoreactivity was found to be colocalized with substance P (SP)-, somatostatin (SST)- and leu-enkephalin (LENK)-like immunoreactivity in the dorsal root- and trigeminal ganglia, the dorsal horn of the spinal cord (laminae I and II), the substantia gelatinosa, and at the lateral border of the spinal nucleus and in the tractus spinalis of the trigeminal nerve. These peptides were also located in fast blue labeled cells of the trigeminal ganglion following injection of the dye into the spinal trigeminal area. This indicates that there are possible sensory projections of these peptides into the spinal trigeminal area. Capsaicin treatment of neonatal rats resulted in a marked decrease in the density of CRF-, SP-, VIP- and CCK-containing neurons in the above mentioned hindbrain areas, whereas SST- and LENK-immunoreactivity were not changed. RIA revealed that, compared to controls, CRF, SP and VIP concentrations in these areas were decreased in rats pretreated with capsaicin, while SST levels were increased; CCK and LENK levels were unchanged. It is concluded that the primary afferent neurons of the nucleus and tractus spinalis of the trigeminal nerve are richly endowed with a number of peptides some of which are sensitive to capsaicin action. The close anatomical proximity of these peptide containing neurons suggests the possibility of a coexistance of one or more of these substances.

Distribution of corticotropin releasing factor-like immunoreactivity in the rat brain by immunohistochemistry and radioimmunoassay: comparison and characterization of ovine and rat/human CRF antisera

The distribution of corticotropin releasing factor (CRF)-like immunoreactivity in the rat brain has been demonstrated by immunohistochemistry and radioimmunoassay using 4 different antisera. Two antisera were directed against synthetic ovine CRF, two antisera were directed against synthetic rat/human CRF. Immunohistochemistry revealed that there are discrete regions where CRF immunoreactive cell bodies are seen with all 4 antisera (e.g., the paraventricular nucleus, the dorsolateral tegmental nucleus) whereas there are cells observed only with one rat CRF antiserum (e.g., in the cortex) or terminal fields observed only with ovine CRF antisera (e.g., the spinal trigeminal tract, the substantia gelatinosa, the spinal cord). Radioimmunoassay showed different cross reactivity of the antisera with synthetic ovine or rat/human CRF and sauvagine, however, there was no cross reactivity with a variety of other peptides. Tissue values of CRF obtained by RIA of micropunched brain nuclei with the 4 antisera were frequently dissimilar suggesting that different antisera recognize different substances. High performance liquid chromatography and radioimmunoassay of brain tissue samples, revealed that there is more than one form of CRF-like immunoreactivity present. There is indirect evidence that there exists at least one peptide in the rat brain, prominent in the medulla and the spinal cord, which cross reacts with antisera directed to ovine CRF only.

Origin of cholinergic nerves to the rat major cerebral arteries: coexistence with vasoactive intestinal polypeptide

The distribution and density of vasoactive intestinal polypeptide (VIP) immunoreactive and acetylcholinesterase (AChE)-containing nerves around the cerebral arteries was studied by using whole mounts with or without lesioning the sphenopalatine ganglia. Abundant VIP immunoreactive and AChE-containing nerves were observed around the cerebral blood vessels in normal rats especially in the anterior circulation of the cerebral arteries. VIP-immunoreactivity and AChE-staining was also demonstrated in neurons within the sphenopalatine ganglia. Lesions of the sphenopalatine ganglia resulted in a marked reduction of both VIP-immunoreactivity and AChE activity. In many neurons, coexistence of both VIP and AChE was revealed. These results demonstrate that cholinergic neurons from the sphenopalatine ganglia innervate the cerebral vasculature at the base of the brain, and that VIP and AChE coexists within the same fibers.

Primate model of parkinsonism: selective lesion of nigrostriatal neurons by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine produces an extrapyramidal syndrome in rhesus monkeys

Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to rhesus monkeys (1.0-2.5 mg/kg i.v.) produces irreversible damage to nigrostriatal neurons. Dopaminergic neurons in the dorsolateral part of striatum were the most vulnerable. The major clinical signs of an extrapyramidal syndrome, but not resting tremor, appeared only in MPTP-treated monkeys suffering from more than 80% reduction in striatal dopamine. No chronic changes in the mesolimbic dopaminergic system were observed. Immunocytochemical staining of the mid-brain with a tyrosine hydroxylase antiserum indicated that MPTP produced a significant decrease of dopaminergic cell bodies in the A9, but not in the A10 ventrotegmental area. Despite greater than 80% decrease in A9 nigral cell bodies, the dopamine content decreased only by 50%. Sprouting of the surviving nigral A9 neurons was observed histologically and neurochemically in the area above substantia nigra. The present behavioral, neurochemical and histological results indicate that MPTP produces an ideal primate model for studying parkinsonism. Selective lesion of more than 80% of the nigrostrial neurons by MPTP is sufficient to produce the major clinical signs of the extrapyramidal syndrome in idiopathic parkinsonism.

Evidence for the existence of atrial natriuretic factor-containing neurons in the rat brain

Immunoreactive atrial natriuretic factor- (ANF-)positive nerve fibers and cell bodies were observed in the preoptic area, hypothalamus, mesencephalon, and pons of rats. In colchicine-treated animals a large number of immunoreactive ANF-positive cell bodies were seen in the organum vasculosum of the lamina terminalis, in several hypothalamic nuclei (e.g. periventricular, arcuate, and ventral premammillary nuclei), and in the dorsolateral tegmental nuclei of the pons. Varicose nerve fibers containing ANF were generally observed in the vicinity of the cells. These findings indicate that a widespread network of ANF-containing neurons is present in the brain.

Identification of neuron-specific enolase and nonneuronal enolase in human and rat brain on two-dimensional polyacrylamide gels

The location of the enzymes neuron-specific enolase and nonneuronal enolase on two-dimensional gels generated from tissue samples obtained from fresh human and rat cortex has been identified. This identification is based upon the following criteria: comigration on polyacrylamide gels with the appropriate purified protein and staining on nitrocellulose protein blots of human and rat cortex using antibodies specific for each protein. The results show that our preparation of neuron-specific enolase from rat and human brain is highly pure, as only one spot is obtained on two-dimensional gels. Further, the antiserum to neuron-specific enolase is highly specific, as it reacts only with neuron-specific enolase on nitrocellulose blots derived from two-dimensional gels of cortical tissue. The location of these proteins is of interest because it positively identifies two major brain proteins on two-dimensional polyacrylamide gels of fresh cortical tissue. This information will be useful in a variety of future studies aimed at both identifying specific proteins on two-dimensional gels and observing the effects of experimental manipulations on brain and other neuronal proteins.

Suggestive evidence for a functional unit between mast cells and substance P fibers in the rat diaphragm and mesentery

A close spatial relationship between serotonin-containing mast cells and substance P-containing nerves was shown by immunohistochemistry using a combination of antisera specific for serotonin and substance P. This supports earlier morphological results suggesting an innervation of mast cells and pharmacological studies which postulate an influence of substance P on the release of histamine from mast cells.

Two-dimensional gel electrophoresis used in neurobiological studies of proteins in discrete areas of the rat brain

Using two-dimensional gel electrophoresis, we studied proteins in the rat brain. The relative amounts of individual proteins differ in discrete areas of the brain, and the concentrations of three different proteins can be altered by chronic administration of desmethylimipramine or reserpine. Brain proteins can be radiolabeled in vitro by incubating samples of fresh tissue with [35S]methionine. We identified several proteins by using immunoblotting and comigration. Finally, we developed a possible animal model for studying proteins related to Alzheimer's disease by depleting the cholinergic innervation to the cortex and the hippocampus.

Two-dimensional gel electrophoresis used in neurobiological studies of proteins in discrete areas of the rat brain

Using two-dimensional gel electrophoresis, we studied proteins in the rat brain. The relative amounts of individual proteins differ in discrete areas of the brain, and the concentrations of three different proteins can be altered by chronic administration of desmethylimipramine or reserpine. Brain proteins can be radiolabeled in vitro by incubating samples of fresh tissue with [35S]methionine. We identified several proteins by using immunoblotting and comigration. Finally, we developed a possible animal model for studying proteins related to Alzheimer's disease by depleting the cholinergic innervation to the cortex and the hippocampus.

Proteins in normal, irradiated, and postmortem human brain quantitatively compared by using two-dimensional gel electrophoresis

Using a combination of two-dimensional gel electrophoresis (2DE), silver staining, and computerized densitometry, we studied protein patterns in human cerebral cortex: normal fresh-frozen, fresh-frozen but previously irradiated, and post-mortem. The relative molecular mass of the resolved proteins ranged from 14 400 to 100 000, the isoelectric points from 4.75 to 7.0. The pattern of proteins (six of them identified) was essentially the same for all three groups. However, computerized densitometry demonstrated significant alterations in the density of several spots in the irradiated and postmortem groups as compared with the normal controls. Irradiated cortex showed statistically significant changes in only six spots (three increased and three decreased in density); postmortem material showed 20 altered spots (16 diminished and four increased). Evidently normal human cerebral cortex has a consistent protein pattern on 2DE, which is quantitatively (but not qualitatively) altered in irradiated and postmortem material. These findings provide a point of reference against which proteins from abnormal brain material can be compared, both qualitatively and quantitatively.

Proteins in normal, irradiated, and postmortem human brain quantitatively compared by using two-dimensional gel electrophoresis

Using a combination of two-dimensional gel electrophoresis (2DE), silver staining, and computerized densitometry, we studied protein patterns in human cerebral cortex: normal fresh-frozen, fresh-frozen but previously irradiated, and post-mortem. The relative molecular mass of the resolved proteins ranged from 14 400 to 100 000, the isoelectric points from 4.75 to 7.0. The pattern of proteins (six of them identified) was essentially the same for all three groups. However, computerized densitometry demonstrated significant alterations in the density of several spots in the irradiated and postmortem groups as compared with the normal controls. Irradiated cortex showed statistically significant changes in only six spots (three increased and three decreased in density); postmortem material showed 20 altered spots (16 diminished and four increased). Evidently normal human cerebral cortex has a consistent protein pattern on 2DE, which is quantitatively (but not qualitatively) altered in irradiated and postmortem material. These findings provide a point of reference against which proteins from abnormal brain material can be compared, both qualitatively and quantitatively.

Primate model of Parkinson's disease: alterations in multiple opioid systems in the basal ganglia

A motor disorder similar to idiopathic Parkinson's Disease develops in rhesus monkeys after several daily repeated doses of N-methyl-4-phenyl, 1,2,3,6-tetrahydropyridine (MPTP). The concentrations of peptides derived from proenkephalin A, proenkephalin B, substance P and somatostatin were measured by specific radioimmunoassays in the basal ganglia of MPTP-treated monkeys. In MPTP-treated monkeys, dynorphin B concentration was reduced in the caudate. In the putamen, the concentrations of peptides derived from both proenkephalin A and proenkephalin B were decreased. In the globus pallidus, the concentrations of all opioid peptides tend to be increased, reaching significance only for alpha-neo-endorphin. In the substantia nigra, only Met-enkephalin concentration was reduced, while other peptides derived from either proenkephalin A or proenkephalin B were not changed. Substance P and somatostatin were not changed in any brain area examined. Some of the symptoms associated with Parkinson's Disease may be related to altered activity of endogenous opiates in basal ganglia.

A study of afferent projections to the rat interpeduncular nucleus

Forebrain and brainstem afferents projecting to the interpeduncular nucleus (IPN) have been demonstrated in male rats by retrograde transport of fluorescent dye, "fast blue," microinjected in IPN, followed by intraventricular colchicine 48 hr prior to perfusion. The most intensely labeled cells projecting to IPN were concentrated throughout the entire rostrocaudal extent of the medial habenular nuclei. A small number of labeled medial habenular cells located dorsomedially also revealed SP immunofluorescence. Additional forebrain afferents originate from septal, hypothalamic and mammillary nuclei. Of brainstem afferents projecting to IPN, the most intensely labeled neurons were present in a circumscribed region overlying the dorsal aspect of the dorsal tegmental nucleus, an area described in the cat as the nucleus incertus [5], and which we now suggest is present in the rat. Many labeled cells in the medial aspect of this nucleus also revealed L-ENK immunofluorescence. Additional brainstem afferents include the raphe, dorsolateral tegmental nuclei and locus coeruleus. This study demonstrates both forebrain and brainstem afferents projecting to IPN and reveals an SP and L-ENK projection from the medial habenula and nucleus incertus, respectively.

The subnuclear distribution of substance P, cholecystokinin, vasoactive intestinal peptide, somatostatin, leu-enkephalin, dopamine-beta-hydroxylase, and serotonin in the rat interpeduncular nucleus

The distribution of immunofluorescent somata and processes within the interpeduncular nucleus (IPN) containing substance P (SP), cholecystokinin (CCK), vasoactive intestinal peptide (VIP), somatostatin (SST), leu-enkephalin (L-ENK), dopamine beta hydroxylase (DBH), and serotonin (5HT) was examined in male rats treated with colchicine 48 hours prior to perfusion. Serial sections were examined for immunofluorescence and variations in the density of fluorescence rated 1 + (sparse) to 4 + (dense). The rostral subnucleus contained SP, SST, and L-ENK-positive somata and processes. Substance P and VIP processes were present throughout the rostral subnucleus but were concentrated in two ovoid areas located dorsally in the caudal region of this subnucleus. Cholecystokinin and L-ENK processes surrounded these ovoid areas. The entire width of the central subnucleus was crossed by SP and L-ENK processes oriented horizontally in narrow bands. Substance P processes were also aligned into vertical columns adjacent to the lateral margins of the central subnucleus. Leu-enkephalin and 5HT processes were distributed throughout this subnucleus, while VIP processes were present only caudally. Dopamine beta hydroxylase processes were evenly distributed but were restricted from the vertical columns laterally. The intermediate subnuclei contained a sparse density of SP and 5HT processes that were present in proximity to the major blood vessels penetrating this subnucleus. Only DBH processes were evenly distributed. The lateral subnuclei contained a dense concentration of SP processes. The medial edges of this subnucleus were distinguished by VIP, CCK, L-ENK, and 5HT processes. The dorsal subnucleus contained 5HT, L-ENK, and SST-positive somata and processes. Substance P, VIP, CCK, and DBH processes were also present. Dorsal-lateral subnuclei contained SP, SST, L-ENK, and DBH processes. Interstitial subnuclei contained SP, CCK, L-ENK, 5HT, and DBH processes. This study demonstrates that perikarya and processes containing peptides and monoamines are distributed within subnuclei of IPN in a topographic and heterogeneous pattern. New features of IPN organization are revealed.

Cardiovascular effects produced by injections of thyrotropin-releasing hormone in specific preoptic and hypothalamic nuclei in the rat

Microinjection of 1.4 pmol TRH (0.5 ng; 50-150 nl) into both the preoptic suprachiasmatic nucleus (pos) and the A7000-6800 region of the medial preoptic nucleus (pom) produced increases in blood pressure and heart rate of 7% and 19%, respectively; heart rate responses in these two areas were higher than those occurring in other areas tested. TRH induced a significant increase in blood pressure and heart rate in the posterior hypothalamic nucleus (nhp) and increased heart rate only in the anterior (nha) and dorsomedial (ndm) hypothalamic nuclei. A small decrease in both blood pressure and heart rate resulted with TRH injections in the A7400-7050 region of the pom. No changes in respiratory rate or rectal temperature were observed at any site with this dose of TRH. Preliminary studies into the mechanism of the cardiovascular actions of TRH suggested that inhibition of the parasympathetic nerves to the heart make a partial contribution to the TRH-induced heart rate increase in the pos and that adrenal catecholamine release mediates the TRH response in the nhp. Neither methylatropine pretreatment nor adrenalectomy prevented the response to TRH injected into the nha, suggesting that activation of the cardiac sympathetic nerves may mediate TRH actions in this region. In the ndm, neither methylatropine nor adrenalectomy prevented the response to TRH; however, there was a tendency for the response to be less after methylatropine. Therefore, both inhibition of the parasympathetic and activation of the sympathetic nervous systems may contribute to the response observed, but no adrenal involvement could be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Capsaicin depletes corticotropin-releasing factor-like immunoreactive neurons in the rat spinal cord and medulla oblongata

Treatment of newborn rats with capsaicin was shown to cause a disappearance of corticotropin-releasing factor immunoreactive nerve fibers in the dorsal horn of the spinal cord (laminae I and II), the spinal trigeminal nucleus and tract, and the nucleus tractus solitarius, but not in the median eminence and the nucleus amygdaloideus centralis. Since it is well known that capsaicin acts selectively on primary sensory neurons of the C-fiber type, it is suggested that corticotropin-releasing factor is also located in peripheral sensory neurons, representing a novel peptidergic neuronal system, possibly involved in the modulation or transmission of peripheral nociceptive impulses, which is different from the capsaicin-resistant hypothalamoinfundibular corticotropin-releasing factor system.

Corticotropin releasing factor-like immunoreactive neurons in the rat retina

Corticotropin releasing factor (CRF)-like immunoreactive neurons have been identified in the rat retina by immunohistochemical methods using antisera directed against ovine and rat CRF. CRF-like immunoreactivity was observed in both amacrine and ganglion cells which projected fine varicose processes to the inner plexiform layer of the retina. It is suggested that CRF may play a role in retinal function.

Effect of desmethylimipramine and reserpine on the concentration of specific proteins in the parietal cortex and the hippocampus of rats as analyzed by two-dimensional gel electrophoresis

The effect of desmethylimipramine (DMI) and reserpine on the concentration of specific proteins in the parietal cortex and the hippocampus of rats was assessed using two-dimensional gel electrophoresis combined with computer-assisted scanning densitometry. Chronic administration of DMI for 3 weeks was found to produce a significant reduction in the concentration of two proteins in both brain regions examined. Both of these proteins have a molecular weight of approximately 57,000 daltons and isoelectric point of 6.2 to 6.3. A third, smaller protein (MW 28,000 daltons, isoelectric point 5.9) was increased in concentration in rats treated repeatedly with DMI. Acute drug treatment was, in all three cases, found to be without effect. In contrast, chronic treatment of rats with reserpine produced effects on these three proteins in the hippocampus which were quantitatively opposite to those obtained after chronic DMI administration. Again, acute drug treatment was without effect. These results demonstrate that chronic, but not acute, administration of agents affecting noradrenergic reactivity can also have an effect on the concentration of specific proteins within the central nervous system and are of interest in view of the known effects of these drugs on neurotransmitter and enzyme systems in the central nervous system.

Cardiovascular effects of discrete intrahypothalamic and preoptic injections of bradykinin

Blood pressure and heart rate were monitored during discrete injections of bradykinin (5 nmol; 100-300 nl) in the hypothalamus and preoptic area of halothane anesthetized rats. In the paraventricular nucleus, bradykinin produced bradycardia without effecting blood pressure. The decrease in heart rate was abolished by pretreatment with methylatropine (IP), suggesting that the parasympathetic nervous system mediates this response. In contrast, in the dorsomedial and posterior hypothalamic nuclei, bradykinin increased both heart rate and blood pressure; methylatropine pretreatment (but not adrenalectomy) blocked these responses, suggesting that inhibition of the parasympathetic nervous system is responsible for the actions of bradykinin in these nuclei. In the preoptic suprachiasmatic nucleus, bradykinin produced an increase in heart rate only, which was attenuated by either methylatropine or adrenalectomy, indicating that both inhibition of the parasympathetic nervous system and adrenal catecholamine release contribute to the actions of bradykinin at this site. The increase in heart rate observed with bradykinin in the medial preoptic and anterior hypothalamic (A6400-6001 region) nuclei was not effected by either methylatropine or adrenalectomy, therefore activation of the sympathetic nervous system may be involved in responses in these regions. Finally, a 5 nmol dose of bradykinin potentiating factor (converting enzyme inhibitor; CEI) had effects similar to bradykinin when injected into the posterior hypothalamus, but no effect at any other brain site. CEI administration into brain sites 15 min prior to bradykinin injections failed to alter the bradykinin response. In summary, the central cardiovascular responses to bradykinin depend upon the specific site of injection and these sites correspond with the localization of bradykinin-like immunoreactivity previously reported by others.

Increases in heart rate and blood pressure produced by injections of dermorphin into discrete hypothalamic sites

Central cardiovascular sites of action for dermorphin were determined by injecting 40 pmol of the peptide into discrete sites within the hypothalamus of halothane anesthetized rats. Blood pressure and heart rate in 101 rats were 88 +/- 1 mm Hg and 338 +/- 3 beats/min, respectively, prior to 100 nl intrahypothalamic injections of either vehicle or dermorphin. In the caudal anterior hypothalamic nucleus (A5800-5300), dermorphin, but not vehicle, increased blood pressure 8% and heart rate 26%, without changing respiration rate. The peak response was at 32 +/- 5 min, the duration greater than 90 min. Injections of naloxone (30 nmol) into the same anterior hypothalamic site, or 3 mg/kg naloxone administered i.m., completely reversed the cardiovascular actions. Similar increases in heart rate and blood pressure occurred at A6600-6300, the region between medial preoptic and anterior hypothalamic nuclei. Small increases in heart rate, but not blood pressure, resulted from dermorphin injections into the septal area, medial preoptic nucleus, paraventricular hypothalamic nucleus and the lateral ventricle, while injections in the posterior and dorsomedial hypothalamic nuclei were without effect on blood pressure and heart rate. These data provide support for anterior hypothalamic and medial preoptic sites for the cardiovascular actions of the opiate receptor agonist, dermorphin, and indicate greatest effects with this dose (primarily on heart rate) are produced at discrete sites (A6600-6300 and A5800-5300) within these nuclei.

Effects of adrenalectomy, propranolol and methylatropine on the increase in heart rate induced by injection of dermorphin in the rat anterior hypothalamic nucleus

Anterior hypothalamic injections of 40 pmol dermorphin, a potent opiate receptor agonist, increased heart rate 17% and had no effect on blood pressure in halothane-anesthetized rats. Administration of the beta-receptor antagonist, propranolol, during the peak response to dermorphin, reduced the heart rate to levels not different from pretreatment control; pretreatment with propranolol completely blocked the tachycardia produced by a subsequent injection of dermorphin. In contrast, neither adrenalectomy nor pretreatment with methylatropine altered the response to dermorphin. These data suggest that increased activity of the sympathetic nervous system, primarily to the heart, and not increased release of adrenal catecholamines or inhibition of parasympathetic nervous system activity, is responsible for the increase in heart rate resulting from injection of dermorphin into the anterior hypothalamic nucleus.

Localization of substance P, acetylcholinesterase, muscarinic receptors and alpha-bungarotoxin binding sites in the rat interpeduncular nucleus

On the basis of acetylcholinesterase (AChE) staining, the rat interpeduncular nucleus was subdivided into five distinct zones. Intense AChE staining was observed in the dorsal cap and the lateral zones. Moderate staining was seen in the median zone and the dorsoventral column. The perivascular zones were unlabeled. Adjacent sections were stained for AChE and for substance P immunofluorescence. Substance P like immunoreactivity was found to coincide with the localization of AChE in the dorsal cap and the lateral zones. Both muscarinic receptors and alpha-bungarotoxin binding sites had distributions resembling that of AChE. Neither unilateral nor bilateral lesions of the habenulae changed the number or distribution pattern of the receptors. It was concluded that cholinergic receptors are localized postsynaptically. Our study suggests AChE and substance P containing fibers terminate in well defined zones of the interpeduncular nucleus which also contain muscarinic and nicotinic receptors.

Phenylethylamine, norepinephrine and mounting behavior in the male rat

Phenylethylamine, which induces mounting behavior in naive adult male rats when administered chronically, was shown to selectively raise brain norepinephrine levels in the medial preoptic nucleus, a region known to be implicated in the regulation of sexual behaviors. It is suggested that the catecholamine alteration is a secondary response to the primary influence of phenylethylamine on the preoptic nucleus.

The development of peptide-containing neurons within neocortical transplants in adult mice

Transplantation of embryonic neocortex into adult host neocortex leads to the survival of many donor cells, with the subsequent differentiation of the cortical neurons within a loosely laminated cellular pattern. We wanted to know whether peptide-containing neurons that are known to exist in normal neocortex would survive in the transplants, and if so, whether they would differentiate into morphological cell types that normally contain these peptides in cortex. By 30 days after transplantation, the implants were well vascularized and the donor neurons appeared healthy in Nissl-stained preparations. AChE-positive axons grew across the interface and innervated the transplant in moderate densities. Immunocytochemical localization of peptides in the transplant revealed that processes containing the four peptides normally present in cortex also develop in the transplants. These were vasoactive intestinal polypeptide, cholecystokinin, pancreatic polypeptide and somatostatin. Other peptides not yet demonstrated in and presumably not present in neocortex, did not develop in the transplants. These included alpha-melanocyte stimulating hormone, arginine-vasopressin, corticotropin releasing factor, beta-endorphin and substance P. The results demonstrate that peptide-immunoreactive neurons survive in neural transplants, where they develop complicated patterns of axonal arborization. The conditions used in these experiments produced no evidence that peptidergic neurons within the transplant grow out of the transplant and into the host brain within six weeks. Similarly, host peptidergic axons were never seen crossing the interface zone and entering the transplant in any significant numbers.

Sex differences in specific proteins in the preoptic medial nucleus of the rat hypothalamus

Using two-dimensional gel electrophoresis and a highly sensitive silver stain, specific proteins in adult male and female rat brain were examined. Based on previous studies, the preoptic medial nucleus (POM) of the hypothalamus served as the area of interest, with the parietal cortex acting as control. A significant difference between the sexes was found in the concentration of two proteins in the POM, a difference which was not found in the parietal cortex.

Mapping and quantitation of proteins from discrete nuclei and other areas of the rat brain by two-dimensional gel electrophoresis

A map of the location and relative concentration of a number of different proteins present in 25 distinct neuroanatomical regions of the male rat brain has been established utilizing two-dimensional polyacrylamide gel electrophoresis. The regions examined include cortical areas as well as nuclei from the hypothalamus, amygdala, thalamus, forebrain, and hindbrain. Tissue samples were obtained from each region of interest by microdissection. Proteins within these samples were first separated by charge using the technique of isoelectric focusing. In the second dimension, proteins were separated by mass on polyacrylamide slab gels containing sodium dodecyl sulfate. Proteins were visualized using a highly sensitive silver stain and quantitated by computerized scanning densitometry. The results demonstrate that all proteins examined varied somewhat in concentration among the different brain regions. The majority (53%) of polypeptides selected for quantitation were found to vary less than 4-fold in concentration between the neuroanatomical areas with the lowest and highest detected amounts. In contrast, approximately 10% of the proteins examined varied widely in the quantity measured in each brain region, with concentration values ranging more than 10-fold between the regions with the lowest and highest detected amounts. This atlas is a first attempt at systematically classifying the mass, charge, and relative concentration of proteins present in a variety of regions of the rat brain. The system presented here will serve as a basis for future studies in this area.

Vasoactive intestinal peptide inhibitory innervation in bovine mesenteric lymphatics. A histochemical and pharmacological study

The localization of vasoactive intestinal peptide-immunoreactive nerves innervating bovine lymphatic vessels was studied by an immunohistochemical technique. Nerve fibers containing vasoactive intestinal peptide immunoreactivity were present in the smooth muscle layers as well as in the adventitia of all mesenteric lymphatics that were examined. The effect of vasoactive intestinal peptide on isolated lymphatic vessels in vitro was studied. Vasoactive intestinal peptide caused a concentration-dependent relaxation of bradykinin-induced contractions of lymphatic vessels. The threshold and maximum relaxations were achieved with vasoactive intestinal peptide at concentrations less than 6 X 10(-9) M and 3 X 10(-7) M, respectively. The relaxant response to vasoactive intestinal peptide was not modified by atropine, propranolol, bretylium, or tetrodotoxin. These results suggest that vasoactive intestinal peptide may be a possible inhibitory neurotransmitter that causes relaxation of lymphatic vessels.

Cardiovascular effects of intrahypothalamic injections of alpha-melanocyte stimulating hormone

Injection of alpha-melanocyte stimulating hormone (alpha-MSH, 0.6-1.2 nmol in 100-300 nl) into the rostral dorsomedial hypothalamic nucleus of the halothane anesthetized rat resulted in a 12% increase in heart rate (41 +/- 4 bpm) which was accompanied by a slight increase in blood pressure (5 +/- 1 mm Hg). The response was characterized by a gradual onset, with a peak increase at 7 +/- 1 min and a duration of 51 +/- 6 min. Tachyphylaxis to the response was apparent for at least 180 min following initial exposure to the peptide. In contrast to the increase in heart rate observed following alpha-MSH injection into the dorsomedial nucleus, injections into the medial preoptic, anterior, paraventricular or posterior hypothalamic nuclei had no significant effects on blood pressure and heart rate. These data suggest a possible role for brain alpha-MSH in the central control of heart rate at a site within the dorsomedial nucleus of the hypothalamus.

Application of high-performance liquid chromatography with electrochemical detection to the determination of catecholamines in microdissected regions of the rat brain

High-pressure liquid chromatography (HPLC) with electrochemical detection was applied for measurement of catecholamines in microdissected tissues from discrete brain regions. Brain areas were dissected, extracted and processed for HPLC assay without further purification. The advantage of this method is its simplicity and relatively low cost and may therefore be applied to the measurement of amines in brain micropunches.

A primate model of parkinsonism: selective destruction of dopaminergic neurons in the pars compacta of the substantia nigra by N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

A syndrome similar to idiopathic parkinsonism developed after intravenous self-administration of an illicit drug preparation in which N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (NMPTP) might have been responsible for the toxicity. In the present study we show that intravenous administration of NMPTP to the rhesus monkey produces a disorder like parkinsonism (akinesia, rigidity, postural tremor, flexed posture, eyelid closure, drooling) that is reversed by the administration of L-dopa. NMPTP treatment decreases the release of dopamine and dopamine accumulates in swollen, distorted axons in the nigrostriatal pathway just above the substantia nigra, followed by severe nerve cell loss in the pars compacta of the substantia nigra and a marked reduction in the dopamine content of the striatum. The pathological and biochemical changes produced by NMPTP are similar to the well-established changes in patients with parkinsonism. Thus, the NMPTP-treated monkey provides a model that can be used to examine mechanisms and explore therapies of parkinsonism.

Localization of GRF-like immunoreactive neurons in the rat brain

The localization of human GRF1-44-immunoreactive neurons was studied in the rat brain. A dense accumulation of GRF-containing fibers was noted in the external layer of the median eminence. Cell bodies were observed in colchicine-treated rats. The most intensely fluorescent cluster of cells was contained in the arcuate nucleus. Other cells were seen on the base of the hypothalamus, within the median forebrain bundle, dorsal and ventral aspects of the ventromedial nucleus, zona incerta and dorsal part of the dorsomedial nucleus. These cells may influence the pulsatile release of pituitary growth hormone.

The effects of pancreatic polypeptides and neuropeptide Y on the rat vas deferens

In order to study the physiological significance of the coexistence of pancreatic polypeptide and norepinephrine (NE) in peripheral noradrenergic nerves, the effects of pancreatic polypeptides of several species were tested on the isolated rat vas deferens. Neuropeptide Y (NPY) was also studied because of its sequence homology to the pancreatic polypeptides. The contractile responses, which were mediated predominantly by activation of noradrenergic nerves following electrical stimulation, were inhibited by bovine pancreatic polypeptide (BPP), human pancreatic polypeptide (HPP), avian pancreatic polypeptide (APP) and NPY in a dose-dependent manner using a constant flow bath. The decreasing order of the inhibitory responses was as follows: BPP = HPP greater than NPY greater than APP. The inhibitory responses produced by BPP and HPP lasted more than 1 hr and displayed a marked tachyphylaxis. In contrast, the inhibitory effects induced by NPY and APP usually returned to the control level after 20-30 min and had minimal tachyphylaxis. The inhibitory action of NPY was still present during alpha-adrenergic blockade. Contractions produced by a single submaximal dose of exogenous NE or serotonin (5-HT) in unstimulated preparations were not affected by pretreatment with NPY. The amplitude of contractions was partially reduced 1 min after pretreatment with BPP or HPP; recovery occurred about 15 min after peptide pretreatment in a constant flow bath. These results suggest that an NPY receptor exists presynaptically in the rat vas deferens and that stimulation of the receptor by NPY inhibits the release of NE from noradrenergic nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

Lesions of the paraventricular nucleus area of the hypothalamus disrupt the suprachiasmatic leads to spinal cord circuit in the melatonin rhythm generating system

The circadian rhythm in melatonin production in mammals is regulated by a suprachiasmatic (SCN) leads to spinal cord leads to pineal circuit. In the present investigation the possible participation of the paraventricular nucleus of the hypothalamus (PVN) in the SCN leads to spinal cord segment of this circuit was investigated in the rat. Bilateral lesions of the PVN area were produced and one to two weeks later melatonin production was evaluated by measuring the activities of the two pineal enzymes required for the formation of melatonin from serotonin, indoleamine N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), and urinary 6-hydroxymelatonin, the major melatonin metabolite. In some cases pineal melatonin was also measured. Control animals received sham-PVN lesions. Histological examination of the lesions indicated that the PVN were bilaterally destroyed 100% in 12 animals. The nighttime pineal melatonin and urinary 6-hydroxymelatonin values in this group were reduced about 90%, nighttime pineal NAT activity was reduced about 98%, and HIOMT activity about 75%. The urinary 6-hydroxymelatonin values of PVN-lesioned animals and animals with denervated pineal glands were similar. In animals with hypothalamic lesions involving less than 30% of the PVN, nighttime values of NAT, HIOMT, and urinary 6-hydroxymelatonin were normal; in animals with 30 to 95% PVN damage these parameters were altered to a small degree. These studies, together with histochemical observations, indicate the SCN neurons responsible for pineal circadian rhythms project to the PVN area of the hypothalamus.

Choline acetyltransferase activity in the nucleus tractus solitarius: regulation by the afferent vagus nerve

The influence of nodose ganglionectomy or transection of the peripheral branches of the afferent vagus nerve on choline acetyltransferase (ChAT) activity in the nucleus tractus solitarius (NTS) was studied. ChAT activity was reduced in the microdissected caudal and intermediate portions of the NTS in vagotomized as well as ganglionectomized rats. However, only the ganglionectomy resulted in the degeneration of medullary nerve fibers. These results suggest that the changes in ChAT activity in the NTS are independent of neuronal degeneration and may be due to transynaptic modulation of ChAT activity by afferent vagal impulses. The presence of ChAT in the sensory nodose projection to the NTS, however, cannot be ruled out.

Effects of time and experience on hippocampal neurochemistry after damage to the CA3 subfield

Bilateral injections of kainic acid into the hippocampal CA3 subfield destroyed the CA 3 pyramidal cells and produced a behavioral impairment, an inability to solve spatial maze problems. The behavior recovered, however, with daily experience in a maze task, and the rate of recovery was accelerated by additional daily experience. This recovery of function could be the result of compensatory changes in the distribution or function of the various hippocampal pathways. In the present experiment, this possibility was investigated neurochemically. Five putative neurotransmitters or their synthetic enzymes were measured in dissected regions of the hippocampal formation. Both the long-term effects of the lesions and the effects of behavioral training were determined. A number of alterations in hippocampal neurochemical systems were detected. Acute changes due to the lesions included a widespread loss of glutamate, and regionally specific decreases in glutamic acid decarboxylase (GAD) activity and cholecystokinin (CCK) and norepinephrine (NE) concentrations. Long-term changes included a decline in choline acetyltransferase (ChAT) activity throughout the hippocampal formation, and increases in NE in certain regions. Behavioral testing prevented the decline of ChAT activity, and increased the concentrations of GAD and CCK. The neurochemical conditions present at the time when trained rats recovered behavioral function may indicate the crucial conditions for the occurrence of the behavior.

Bovine pancreatic polypeptide-like immunoreactive nerves in the rat major cerebral arteries

Immunofluorescence histochemical observation of the major cerebral arteries of the rat demonstrated the presence of an extensive plexus of bovine pancreatic polypeptide (BPP) containing nerves. The density of the nerves were similar to those previously observed in the adrenergic plexus. The density of BPP-immunoreactive fibers markedly decreased following bilateral superior cervical ganglionectomy. It is concluded that BPP-containing fibers of the cerebral arteries emanate mostly from the superior cervical ganglion and that BPP and norepinephrine coexist in the adrenergic nerves.

The coexistence and release of bovine pancreatic polypeptide-like immunoreactivity from noradrenergic superior cervical ganglia neurons

The coexistence of bovine pancreatic polypeptide-like (BPP) immunoreactivity within the cell bodies and axons of the superior cervical ganglia (SCG) was studied. Adjacent sections stained by the indirect immunofluorescence technique for either BPP or dopamine-beta-hydroxylase (DBH) revealed that virtually all (90-95%) SCG cells contained DBH and a subpopulation (30-50%) also contained BPP. Ligation of the pre- and postganglionic nerves of the SCG demonstrated BPP-positive fibers emanating from the SCG via both axonal trunks. BPP-containing fibers were also observed entering the SCG via the preganglionic nerve. The peptide was co-released with catecholamine by electrical stimulation of the preganglionic cervical sympathetic nerve trunk, but was not effected by reserpine. The extensive distribution and unique coexistence of a PP-like peptide with peripheral sympathetic nerves suggests a neuromodulatory role in autonomic functions.

Cholinergic projection sites of the nucleus of tractus diagonalis

The cholinergic projection sites of the basal portion of the nucleus of the tractus diagonalis (td) were studied following bilateral stereotaxic lesions. Choline acetyltransferase (ChAT) activity was measured in various cortices, hippocampus and amygdala. Significant decreases in ChAT activity were observed in the anterior and posterior cingulate cortex, the frontal cortex, occipital cortex, hippocampus and dentate gyrus. It is concluded that (1) the hippocampus is innervated by the basal portion of the td and not from the medial septal nucleus, (2) the td contains cholinergic cell bodies which project widely to the cortex and hippocampus. It is suggested that these cholinergic projections have important influences on emotional behavior via connections with the cortex and limbic system.

Vasoactive intestinal polypeptide immunoreactive and cholinergic nerves in the whole mount preparation of the major cerebral arteries of the rat

An immunofluorescence histochemical study of vasoactive intestinal polypeptide (VIP) was made in the major rat cerebral arteries of the whole mount preparation. A comparison was made between the distribution of VIP-immunoreactive and cholinergic nerves. An abundant number of VIP-containing nerves were observed in the internal carotid, anterior cerebral, middle cerebral and basilar artery. VIP and cholinergic nerves were unaffected by bilateral superior cervical ganglionectomy. The density and distribution of VIP-immunoreactive fibers was essentially the same as that of the cholinergic fibers of the rat cerebral vasculature. It is suggested that, as was previously demonstrated in other peripheral organs, VIP coexists within cholinergic neurons of the rat cerebral arteries.

Catecholamines and vasopressin in hindbrain nuclei of hypertension prone and resistant rats

Norepinephrine and epinephrine concentrations in the caudal and rostral part of the nucleus tractus solitarii (NTS) and in locus coeruleus (LC) of Sabra hypertension prone (SBH) rats are 2-4-fold higher than in the parent Sabra (SB) strain; SB rats have higher concentrations than the Sabra hypertension resistant (SBN) rats. Dopamine concentrations were higher in SBH as compared to SB and SBN rats only in the caudal NTS. Vasopressin concentrations in the NTS of SBH were 3-fold higher than the levels found in SB or SBN rats. These data suggest that catecholamines and vasopressin in specific brainstem nuclei are involved in either the pathogenesis or central response to hypertension in SBH rats.

The distribution of corticotropin releasing factor-like immunoreactive neurons in rat brain

Using the indirect immunofluorescent technique, corticotropin releasing factor (CRF)-like immunoreactive nerve fibers and cell bodies were observed to be widely distributed in rat brain. A detailed stereotaxic atlas of CRF-like immunoreactive neurons was prepared. Large numbers of CRF-containing perikarya were observed in the nucleus paraventricularis, with scattered cells in the following nuclei: accumbens, interstitialis stria terminalis, preopticus medialis, supraopticus, periventricularis hypothalami, amygdaloideus centralis, dorsomedialis, substantia grisea centralis, parabrachialis dorsalis and ventralis, tegmenti dorsalis lateralis, vestibularis medialis, tractus solitarius and reticularis lateralis. The most intense staining of CRF-containing fibers was observed in the external lamina of the median eminence. Moderate numbers of CRF-like fibers were observed in the following nuclei: lateralis and medialis septi, tractus diagonalis, interstitialis stria terminalis, preopticus medialis, supraopticus, periventricularis thalami and hypothalami, paraventricularis, anterior ventralis and medialis thalami, rhomboideus, amygdaloideus centralis, habenulae lateralis, dorsomedialis, ventromedialis, substantia grisea centralis, cuneiformis, parabrachialis dorsalis and ventralis, tegmenti dorsalis lateralis, cerebellum, vestibularis medialis, reticularis lateralis, substantia gelatinosa trigemini and lamina I and II of the dorsal horn of the spinal cord. The present findings suggest that a CRF-like peptide may be involved in a neurotransmitter or neuromodulator role, as well as a hypophysiotropic role.

Coexistence of bovine pancreatic polypeptide-like immunoreactivity and catecholamine in neurons of the ventral aminergic pathway of the rat brain

The coexistence of bovine pancreatic polypeptide (BPP) within the cell bodies and axons of noradrenergic neurons of the rat brain was studied. Adjacent hindbrain sections stained by the indirect immunofluorescence technique for either BPP or dopamine-beta-hydroxylase (DBH) revealed A1 and A2 cell bodies containing both antigens. Following bilateral knife cuts of the ventral noradrenergic bundle (VB), the localization of BPP, DBH and catecholamine within the VB and terminal fields of the hypothalamus was determined. An axoplasmic buildup of BPP immunofluorescent material was observed caudal to the knifecut together in the same axonal fields as catecholamine and DBH-containing axons. In the hypothalamus there was a marked decrease in the number of catecholamine-containing nerve fibers. However, there was no obvious decrease in the number of BPP fibers. The influence of high intraventricular doses of 6-hydroxydopamine on BPP and DBH-containing nerves in the hypothalamus was studied. While there was a marked reduction in DBH immunoreactive fibers, BPP fibers appeared relatively unchanged. These results suggest that BPP coexists within some hindbrain catecholamine neurons and their axons. It is suggested that BPP and catecholamine coexist in terminal fields within the hypothalamus. Failure to reveal a decrease in the BPP-fibers in these fields suggests that sprouting of arcuate nucleus derived non-aminergic BPP-containing fibers has occurred.

Secretin in the rat hypothalamo-pituitary system: localization, identification and characterization

Secretin-like immunoreactivity (SLI) has been identified and characterized in the pituitary of the rat. The concentration in the neurointermediate lobe is about 45 fold higher than the concentration of SLI observed in the anterior lobe. Transections of the pituitary stalk of the rat caused a significant depletion of SLI in the neurointermediate lobe without affecting the content in the anterior lobe. In view of the relatively high concentration of SLI reported to occur in the hypothalamus, it appears that there may be a secretinergic pathway between the brain and the neurointermediate lobe of the pituitary.

Bovine pancreatic polypeptide-like immunoreactivity in brain and peripheral nervous system: coexistence with catecholaminergic nerves

The rat central and peripheral nervous system contains a widespread distribution of BPP-like immunoreactive neurons. Some of these neurons coexist with a catecholamine, probably mostly NE. This peptide appears to be releaseable by nerve stimulation. Catecholamine releasing agents such as reserpine do not appear to deplete the BPP. This extensive distribution and unique coexistence of a peptide with peripheral sympathetic nerves suggests a neuromodulatory role of BPP in autonomic functions.

Mechanisms involved in central cardiovascular effects of prostaglandin F2 alpha

Prostaglandin F2 alpha (PGF2 alpha) injected into the cerebroventricular system (icv) of halothane-anesthetized rats increased the arterial blood pressure, heart rate, and rectal temperature. These effects were accompanied by a preferential increase in plasma norepinephrine concentration. Plasma levels of epinephrine, renin, and vasopressin were not changed in the PGF2 alpha-icv-treated rats. Bilateral vagotomy did not affect the PGF2 alpha-induced hypertension and tachycardia nor was there any change in the selective increase in plasma norepinephrine concentration. Hexamethonium pretreatment suppressed, in a dose-response manner, the increases in blood pressure, heart rate, and rectal temperature in response to PGF2 alpha-icv. Plasma norepinephrine and epinephrine levels were not altered by PGF2 alpha-icv in hexamethonium-treated rats, but plasma vasopressin concentration was markedly elevated in all hexamethonium-infused rats. These results suggest that selective central activation of the sympathetic nervous system underlies the profound cardiovascular and temperature responses elicited by central administration of PGF2 alpha.