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PubMed1996

Expression of tachykinin NK1 receptor mRNA in dorsal root ganglia of the mouse.

We examined whether mRNA coding for tachykinin NK1 receptor is expressed in the dorsal root ganglion (DRG) of the mouse, using reverse transcription-polymerase chain reaction (RT-PCR). Both the RT-PCR of the total RNA from the DRGs using four pairs of primers and the digestion of these products with the restriction enzymes gave bands with the predicted length. Further amplification (nested PCR) of part of one PCR product also gave a band with the predicted length. Southern blot hybridization of RT-PCR products of total RNA from the DRG and several CNS regions revealed that the expression level of NK1 receptor mRNA in the DRG was similar to the cerebellum and less than the olfactory bulb, cerebral cortex, medulla oblongata and spinal cord. The present results suggest that NK1 receptor mRNA is expressed in the mouse DRG, although the level is relatively low.

Animals↗
PubMed1981

Secretin immunoreactivity in rat and pig brain.

Secretin immunoreactivity in rat and pig brain has been identified and characterized utilizing a highly specific radioimmunoassay and fractionation on a high pressure liquid chromatographic system reverse phase column. One immunoreactive peak from each brain extract was observed. Secretin immunoreactivity from rat brain and duodenum coelute, but eluted slightly ahead of the immunoreactivity from pig brain and duodenum and from synthetic porcine secretin. Immunoreactive secretin is widely distributed in the thalamus, hypothalamus and olfactory bulb, cerebral cortex, midbrain, septum, striatum, hippocampus, medulla and pons. The highest concentrations occur in the pineal and the pituitary gland.

Animals↗
PubMed1994

Distribution of FMRFamide-like immunoreactivity in the brain of the lizard Podarcis sicula.

The distribution of FMRFamide-like immunoreactive peptides was investigated in the brain of the lizard, Podarcis sicula, using the indirect immunofluorescence technique. The main populations of FMRFamide-immunoreactive cell bodies were located in the forebrain. In the telencephalon, FMRFamide-containing neurons were found both in the pallium and subpallium, namely in the medial cortex, the anterior olfactory nucleus, the nucleus accumbens, the septal nuclei, the nucleus of the medial forebrain bundle, and the nucleus of the diagonal band of Broca. In the diencephalon, a dense accumulation of FMRFamide-immunoreactive neurons was observed in the area preoptica lateralis, the nucleus suprachiasmaticus, the nucleus periventricularis hypothalami, the area lateralis hypothalami, and the dorsal region of the nucleus geniculatus lateralis. In the midbrain, sparse immunoreactive perikarya were found in the tegmentum of the mesencephalon. FMRFamide-immunoreactive fibers were visualized in all regions containing positive cell bodies. In particular, dense bundles of immunoreactive processes were seen in the area preoptica lateralis, in the hypothalamus, and in the median eminence. The tectum and the basal mesencephalon were also densely innervated. Conversely, the caudal brain stem only exhibited scarce immunoreactive processes. The distribution pattern of FMRFamide-immunoreactive neurons in the brain of Podarcis sicula exhibits a number of similarities with that reported in mammals, but significantly differs from that reported in amphibians and fish, suggesting that the neuromodulatory functions of FMRFamide may have diverged during the emergence of terrestrial life.

Age Factors↗
PubMed1992

Molecular characterization of D2 dopamine-like receptors from brain and from the pituitary gland.

D2 dopamine-like receptors have been purified from five bovine brain regions (caudate nucleus, putamen, olfactory tubercle, frontal cortex, cerebellum) and the anterior and neurointermediate lobes of the pituitary gland using a combined ligand-affinity and lectin-affinity chromatography procedure. In all the brain regions except cerebellum and in the neurointermediate lobe of the pituitary gland the purified species appeared as a M(r) 95,000 doublet on SDS-PAGE. In the anterior lobe of the pituitary an additional M(r) 142,000-145,000 species was seen. The M(r) 95,000 species had a low affinity for the lectin wheat germ agglutinin (WGA) whereas the M(r) 142,000-145,000 species had a higher affinity for WGA and additionally showed some affinity for concanavalin A. It is concluded that both the M(r) 95,000 and 142,000-145,000 species are D2 dopamine-like receptors and that the differences between the species are mainly at the oligosaccharide level. Some evidence was also obtained for heterogeneity at the protein level which may correspond to the D2(short) and D2(long) isoforms of these receptors.

Animals↗
PubMed1986

Radioautographic evidence that axons from the area of supraoptic nuclei in the rat project to extrahypothalamic brain regions.

The axonal efferents of neurons of the supraoptic nucleus area were studied by radioautography in the rat after discrete stereotaxic injections of [3H]leucine into this nucleus. Beside a densely labeled pathway running from the nucleus to the posterior pituitary through the internal median eminence, several of the visualized labeled axonal bundles were found to project into various extrahypothalamic regions, including the olfactory bulb, the cortex, the lateral habenula, the subcommissural organ, the amygdala, the mammillary bodies and the locus coeruleus. These results suggest that part of the vasopressin- or oxytocin-containing perikarya located in the supraoptic nucleus constitute the cells of origin of axons which also contain these peptides and which have already been shown to be present in the above extrahypothalamic areas. This also implies that, like the paraventricular nucleus, the supraoptic nucleus is also involved in central extrahypothalamic regulations.

Animals↗
PubMed1993

Immunohistochemical localization of a metabotropic glutamate receptor, mGluR5, in the rat brain.

A trpE-fusion protein containing a C-terminal sequence of a rat metabotropic glutamate receptor, mGluR5, was used to produce an antibody. On immunoblot, the antibody specifically reacted with mGluR5 expressed in mammalian cells and rat brain. Immunohistochemical analysis revealed intense mGluR5-like immunoreactivity (LI) in the olfactory bulb, anterior olfactory nuclei, olfactory tubercle, cerebral cortex, hippocampus, lateral septum, striatum, nucleus accumbens, inferior colliculus, and spinal trigeminal nuclei. The distribution pattern of mGluR5-LI corresponds very well with that of mGluR5 mRNA. Electron microscope analysis of the striatum revealed dense accumulation of immunoreaction products in dendrites which were often provided with asymmetrical synapses. These results suggest that mGluR5 is predominantly located in postsynaptic elements.

Animals↗
PubMed1994

Expression of ciliary neurotrophic factor receptor mRNA and protein in the early postnatal and adult rat nervous system.

We have used reverse transcription/polymerase chain reaction (RT-PCR) and Western blotting with an anti-peptide antibody to study the expression of the alpha-component of the receptor for ciliary neurotrophic factor (CNTFR alpha) in rat nervous tissue. At the early postnatal stage CNTFR alpha protein could be detected in all parts of the nervous system studied (and also in muscle and liver). It was particularly abundant in pons, cerebellum, spinal cord, retina and sciatic nerve. In adult tissues the content was dramatically reduced except for olfactory bulb and cortex, where CNTFR alpha protein was upregulated during development. Only in part of the tissues, expression of CNTFR alpha mRNA and its developmental regulation paralleled that of the protein. These differences are partly explainable by the different cellular localization of mRNA and the membrane associated receptor protein, but, in addition, they suggest the existence of different regulatory mechanisms for CNTFR alpha. Our results support the idea that CNTF plays an important role during the development of the nervous system and that CNTF actions may be found in many brain regions and target cells.

Animals↗
PubMed1996

Fos oncoprotein expression in the rat forebrain following muscimol-induced absence seizures.

Fos oncoprotein expression is a marker of neuronal activation following seizures. Here, using this method we examined the anatomical locations of muscimol-induced absence seizures in the rat forebrain. Six hours after a systemic injection of muscimol a massive Fos immunoreactivity appeared in the olfactory system, retrosplenial cortex and paraventricular thalamic nucleus, whereas other cortical areas contained low level of Fos expression. These results provide the first functional morphological evidence suggesting that these forebrain structures with Fos expression may play an important role in the pathophysiology of muscimol-induced absence seizures.

Animals↗
PubMed1996

Expression of a developmentally-regulated neuron-specific isoform of the neurofibromatosis 1 (NF1) gene.

Neurofibromatosis 1 (NF1) is a common autosomal dominant disorder in which affected individuals develop benign and malignant tumors as well as non-tumor-related abnormalities, such as seizures and learning disabilities. Here, we report an NF1 isoform arising from the alternative splicing of exon 9a with predominant central nervous system (CNS) expression. Exon 9a expression is enriched in neurons of the forebrain, specifically septum, striatum, cortex, hippocampus and olfactory bulb with significantly less expression in brainstem, cerebellum and spinal cord. This pattern of NF1 exon 9a expression correlates with the postnatal maturation of these neurons and suggests a role for NF1 in neuronal differentiation.

Animals↗
PubMed1994

A possible inhibitory action of baclofen on hippocampus GABAergic neurones.

1. The function of the gamma-aminobutyric acid (GABA)ergic system in certain areas of the rat brain was investigated after baclofen treatment (30 mg/kg for 4 days). 2. Two h after the last dose of baclofen GAD activity was reduced in the hippocampus without changes in GABA levels. 24 h after baclofen, GAD activity was increased and the GABA content was decreased. 3. 48 h after the last dose both parameters returned to control values. 4. These results were not observed in any of the other areas investigated: frontal cerebral cortex, corpus striatum, olfactory bulbs, and medio basal hypothalamus. 5. In conclusion, the present study shows that baclofen 30 mg/kg for 4 days, induces an inhibitory action on hippocampus GABAergic neurones, which begins to disappear after 24 h free of drug.

Animals↗
PubMed1986

Autoradiographic localization and pharmacology of unique [3H]tryptamine binding sites in rat brain.

The distribution and pharmacological specificity of [3H]tryptamine binding to coronal and horizontal sections of the rat brain were investigated with computer-assisted autoradiography. [3H]Tryptamine bound to brain regions with up to 58% specificity, as determined with 10 microM tryptamine as a displacer. The capacity (Bmax) of saturable [3H]tryptamine binding sites was greatest in the nucleus accumbens and claustrum (660-760 fmol mg protein-1), with intermediate binding site concentrations in hippocampus, septum, olfactory tubercle, frontal cortex, cingulate cortex and caudate-putamen. The phenylalkylamine, p-methoxyphenylpropylamine and the beta-carboline, harmaline, as well as 5-methyl-tryptamine, displaced [3H]tryptamine from each of these brain regions with a potency that approximated the 5-9 nM affinity (Kd) of [3H]tryptamine binding to each site. Only micromolar concentrations of serotonin displaced [3H]tryptamine, which did not bind to S1, S2, D1, D2 or alpha- or beta-adrenergic sites. The unique pharmacology and the regional overlap of [3H]tryptamine binding sites with dopaminergic nerve terminals in the nucleus accumbens and caudate-putamen suggest that tryptamine-containing neurons in the mammalian brain may modulate behavioral functions such as locomotion.

Animals↗
PubMed1987

Autoradiographic mapping of [mono[125I]iodo-Tyr10, MetO17]vasoactive intestinal peptide binding sites in the rat brain.

The distribution of vasoactive intestinal peptide binding sites in the rat brain was examined by in vitro autoradiography on slide-mounted sections. A fully characterized monoiodinated form of vasoactive intestinal peptide (M-[125I]VIP) previously shown to maintain in the central nervous system the full biological activity of native vasoactive intestinal peptide was used for this study. In initial kinetic and pharmacological experiments the binding of M-[125I]vasoactive intestinal peptide to slide-mounted sections was shown to be time-dependent, saturable and reversible. Association of M-[125I]VIP specific binding was maximal within 90-120 minutes. Specific binding, corresponding to approximately 50% of total binding was saturable, of high affinity (Kd of 76.6 pM) and low capacity (fmol/mg prot range). Dissociation of M-[125I]VIP was maximal at 10 minutes. Unlabeled vasoactive intestinal peptide and the two structurally related peptides "peptide-histidine-isoleucine" (PHI) and secretin competed in a concentration-dependent manner for sites labeled by M-[125I]vasoactive intestinal peptide with the following rank order of potencies: vasoactive intestinal peptide greater than PHI greater than secretin. Vasoactive intestinal peptide receptors, as revealed by quantitative autoradiography, are present at various levels of the neuraxis. High densities were observed in olfactory bulb, cerebral cortex (highest in layers I, II, IV and VI), dentate gyrus, subiculum, various thalamic and hypothalamic nuclei, superior colliculus, locus coeruleus, area postrema, subependymal layer and pineal gland. Intermediate densities were found in the amygdala, nucleus accumbens, caudate-putamen, septum, bed nucleus of the stria terminalis, CA1 to CA4 fields of the hippocampus and central gray. No specific binding of M-[125I]vasoactive intestinal peptide was observed in white matter tracts such as corpus callosum, anterior commissure, medial forebrain bundle and fornix. The mapping of M-[125I]vasoactive intestinal peptide binding sites as revealed by autoradiography on slide-mounted sections indicates an association, although not exclusive, of vasoactive intestinal peptide receptors with brain regions involved in the processing of specific sensory inputs.

Animals↗
PubMed1990

Distribution of nerve growth factor receptor-like immunoreactivity in the adult rat central nervous system. Effect of colchicine and correlation with the cholinergic system--I. Forebrain.

Nerve growth factor receptor, as recognized by the monoclonal antibody 192-IgG, was localized to multiple regions of the adult rat forebrain. Immunoreactive cell bodies and fibers were seen in both sensory and motor regions which are known to contain cholinergic and non-cholinergic neurons. Specifically, nerve growth factor receptor immunoreactivity was present in cells lining the olfactory ventricle, rostral portion of the lateral ventricle, in basal forebrain nuclei, caudate putamen, globus pallidus, zona incerta and hypothalamus. Immunoreactive cells which were situated subpially along the olfactory ventricle and anterior portions of the lateral ventricle, and in the arcuate nucleus resembled neuroglia but could not definitively identified at the light microscopic level. Animals pretreated with intracerebroventricular colchicine displayed significantly increased nerve growth factor receptor immunoreactivity in all previously positive neurons and particularly in the medial preoptic area and ventral premammillary nucleus of the hypothalamus. In such animals, receptor immunoreactivity also appeared in previously non-immunoreactive cells of the hippocampal CA3 region and polymorph layer of the dentate gyrus as well as in the mitral cell layer of the olfactory bulb. Nerve growth factor receptor-immunoreactive fibers and varicosities were seen in the olfactory bulb, piriform cortex, neocortex, amygdala, hippocampus, thalamus, olivary pretectal nucleus and hypothalamus. In most regions, such fiber-like immunoreactive structures likely represented axon terminals, although in some areas, neuroglial or extracellular localizations could not be excluded. In this context, diffuse, non-fibrillar receptor immunoreactivity occurred in the lateral habenular nucleus and medial terminal nucleus of the accessory optic tract. Furthermore, intense nerve growth factor receptor immunoreactivity occurred along certain regions of the pial surface on the ventral surface of the brain. The distribution of nerve growth factor receptor-immunoreactive cell bodies and fibers in multiple sensory and motor nuclei suggests wide-spread influences of nerve growth factor throughout the adult rat forebrain. There is a high degree of overlap with regions containing choline acetyltransferase immunoreactivity. However, significant disparities exist suggesting that certain nerve growth factor receptor-containing non-cholinergic neurons of the rat forebrain may also be affected by nerve growth factor.

Animals↗
PubMed1995

An immunohistochemical study of Ca2+/calmodulin-dependent protein kinase IV in the rat central nervous system: light and electron microscopic observations.

We observed the distribution pattern of Ca2+/calmodulin-dependent protein kinase IV in rat brain and spinal cord using an immunohistochemical method by light and electron microscopy. Particularly strong immunoreactivity was detected in the telencephalic structures such as the olfactory bulb, cerebral cortex, hippocampal formation, caudate-putamen, most nuclei of the dorsal thalamus and the granule cell layer of the cerebellum. Relatively weak staining was observed in the amygdaloid body, some neuron groups of the brainstem reticular formation, the inferior olivary nucleus and the posterior horn of the spinal cord. Immunohistochemical reactivity was not detected in the globus pallidus, substantia nigra, sensory and motor nuclei of the cranial nerves, or in the spinal cord anterior horn. Overall, the distribution of Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity broadly paralleled the sites of expression of signals for messenger RNA of this enzyme. At the subcellular level, Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity appeared exclusively in the nuclei of neurons in the various brain regions, and immunopositive reactivity, although less strong, was also observed in dendritic processes, as well as on the granular endoplasmic reticulum in neuronal somata in these areas. Axon terminals, however, did not show immunoreactivity. These studies demonstrate that Ca2+/calmodulin-dependent protein kinase IV-like immunoreactivity is distributed widely in the central nervous system. The significance of the localization of this enzyme in nuclei is discussed in relation to gene expression.

Animals↗
PubMed1995

Corticotropin-releasing factor receptors: physiology, pharmacology, biochemistry and role in central nervous system and immune disorders.

Corticotropin-releasing factor (CRF) plays a major role in coordinating the endocrine, autonomic, behavioral and immune responses to stress through actions in the brain and the periphery. CRF receptors identified in brain, pituitary and spleen have comparable kinetic and pharmacological characteristics, guanine nucleotide sensitivity and adenylate cyclase-stimulating activity. Differences were observed in the molecular mass of the CRF receptor complex between the brain (58,000 Da) and the pituitary and spleen (75,000 Da), which appeared to be due to differential glycosylation of the receptor proteins. The recently cloned CRF receptor in the pituitary and the brain (designated as CRF1) encodes a 415 amino acid protein comprising seven putative membrane-spanning domains and is structurally related to the calcitonin/vasoactive intestinal peptide/growth hormone-releasing hormone subfamily of G-protein-coupled receptors. A second member of the CRF receptor family encoding a 411 amino acid rat brain protein with approximately 70% homology to CRF1 has recently been identified (designated as CRF2); there exists an additional splice variant of the CRF2 receptor with a different N-terminal domain encoding a protein of 431 amino acids. In autoradiographic studies, CRF receptors were localized in highest densities in the anterior and intermediate lobes of the pituitary gland, olfactory bulb, cerebral cortex, amygdala, cerebellum and the macrophage-enriched zones and red pulp regions of the spleen. CRF can modulate the number of CRF receptors in a reciprocal manner. For example, stress and adrenalectomy increase hypothalamic CRF secretion which, in turn, down-regulates CRF receptors in the anterior pituitary. CRF receptors in the brain and pituitary are also altered as a consequence of the development and aging processes. In addition to a physiological role for CRF in integrating the responses of the brain, endocrine and immune systems to physiological, psychological and immunological stimuli, recent clinical data implicate CRF in the etiology and pathophysiology of various endocrine, psychiatric, neurologic and inflammatory illnesses. Hypersecretion of CRF in the brain may contribute to the symptomatology seen in neuropsychiatric disorders, such as depression, anxiety-related disorders and anorexia nervosa. Furthermore, overproduction of CRF at peripheral inflammatory sites, such as synovial joints may contribute to autoimmune diseases such as rheumatoid arthritis. In contrast, deficits in brain CRF are apparent in neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease and Huntington's disease, as they relate to dysfunction of CRF neurons in the brain areas affected in the particular disorder. Strategies directed at developing CRF-related agents may hold promise for novel therapies for the treatment of these various disorders.

Alzheimer Disease↗
PubMed1985

Glycine receptor distribution in mouse CNS: autoradiographic localization of [3H]strychnine binding sites.

Biochemical and electrophysiological studies of mammalian CNS indicate that the amino-acid, glycine, is a major inhibitory neurotransmitter whose location is, for the large part, confined to the spinal cord and brain stem. In this study, autoradiographs of C57BL/6J mouse brain sections labeled with [3H] strychnine, a potent antagonist of glycine, were used to map the distribution of glycine receptors in the CNS. Autoradiographs showed highly localized areas of grain density, which confirmed the gross distributions described in homogenate binding studies and gave a more precise regional localization of glycine receptors in this animal. The highest overall labeling was observed in the spinal cord and medulla; areas of highest grain density included the dorsal horn of the spinal cord, the cranial nerve nuclei, the dorsal column nuclei and nuclei of the medullary reticular formation. A decrease in overall grain density was observed rostrally throughout the midbrain and pons; in caudal regions, however, dense labeling was observed over the trigeminal, vestibular and facial nuclei and over the major nuclei of the auditory system. In more rostral areas, the interpeduncular nucleus and the substantia nigra were also clearly delineated, as were certain thalamic nuclei. The cerebellum, cortex, hippocampus and olfactory bulbs showed only very low levels of grain density. In summary, it appears that high concentrations of glycine receptors in the brain and spinal cord may be preferentially localized to neurons involved in the processing of information originating from exteroceptive sensory mechanoreceptors.

Animals↗
PubMed1987

Quantitative autoradiographic analysis of somatostatin binding sites in discrete areas of rat forebrain.

Somatostatin has been localized in several hypothalamic and extrahypothalamic brain regions where it may function as a classical neurotransmitter or as a modulator of neural activity. In the present study, somatostatin binding sites were studied by incubation of coronal sections of rat forebrain with 125I-Tyr1-somatostatin, Ultrofilm autoradiography, computerized microdensitometry and comparison with 125I standards. Highest concentrations of somatostatin binding sites (fmol/mg protein) were found in the claustrum (151), basolateral nucleus of the amygdala (90), deep layers of the cerebral cortex (61), lateral olfactory nuclei (58), CA1 and CA2 areas of hippocampus (57), medial and lateral septal nuclei (54), and the medial habenula (44). Scatchard analysis of individual forebrain areas with high densities of somatostatin binding sites was also performed. Regulation of brain somatostatin binding sites may be studied as one approach to examining the involvement of central somatostatin pathways in various physiological and behavioral states.

Animals↗
PubMed1995

Massive activation of c-fos in forebrain after mechanical stimulation of the locus coeruleus.

Brief implantation of a 33-ga cannula in the locus coeruleus (LC) of the rat caused widespread and intense ipsilateral activation of c-fos throughout the forebrain. Areas showing heavy staining included the cingulate, piriform, parietal, frontal cortex, and the olfactory tubercle. Prior lesion of the LC with 6-hydroxydopamine (6-OHDA) abolished the response. It is concluded that the mechanical stimulation and/or trauma involved in the implantation of a cannula in the LC is sufficient to cause widespread activation of noradrenergic neurotransmission throughout the forebrain. The use of this procedure for drug delivery should therefore be reevaluated.

Animals↗