Reinnervation of sympathetically denervated rat iris by superior cervical ganglion cells has been demonstrated to occur in vitro. Return of [(3)H]norepinephrine uptake by irises incubated in contact with ganglia was associated with the reappearance of nerve fibers containing catecholamines that were demonstrable by fluorescent histochemistry. The reinnervating neurons appeared to follow the same general pattern of innervation seen in the normal iris, but the density of the neural plexus was much greater. Nerve growth factor influenced the rate and extent of innervation of the iris but not of neuronal growth within the ganglion.

Animals↗

PubMed1968

Direct adrenergic innervation of a teleost melanophore.

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Animals↗

PubMedDate not supplied

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.

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PubMedDate not supplied

Changes in alpha-melanotropin in discrete brain areas of isolated aggressive mice.

Adult male Swiss-Webster (NIH) mice were isolated for 6 weeks. Aggressive behavior was tested on 2 occasions, 24 hours apart. Immediately following the 2nd test period, aggressors and isolated non-aggressors (controls) were decapitated and alpha-MSH concentration was measured in discrete areas of the brain. Only the nucleus accumbens and preoptic lateralis of the aggressors, showed a higher level of alpha-MSH when compared to the controls. The significance of these changes is discussed.

Aggression↗

PubMedDate not supplied

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.

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PubMedDate not supplied

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.

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PubMedDate not supplied

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.

Animals↗

PubMedDate not supplied

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.

Animals↗

PubMedDate not supplied

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)

Adrenergic Fibers↗

PubMedDate not supplied

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)

Animals↗

PubMedDate not supplied

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.

Acetylcholinesterase↗

PubMedDate not supplied

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.

Animals↗