Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biochemical assays on microdissected samples, denervation studies, subcellular fractionation, and light and electron microscopic autoradiography of high affinity uptake have been performed to study the cellular localization of transmitter candidates in the rat hippocampal formation. High affinity uptake of glutamate and aspartate is localized in the terminals of several excitatory systems, such as the entorhino-dentate fibres (perforant path), mossy fibres (from granular cells) and pyramidal cell axons. Thus, in stratum radiatum and oriens of CA1, 85% of glutamate and asparate uptake and 40% of glutamate and aspartate content are lost after lesions of ipsilateral plus commissural fibres from CA3/CA4. Hippocampal efferents also take up aspartate and glutamate, since these activities are heavily reduced in the lateral septum and mamillary bodies after transection of fimbria and the dorsal fornix. The synthesis (by glutamic acid decarboxylase), content and high affinity uptake of gamma-aminobutyrate (GABA) are not reduced after lesions of these or other projection fibre systems. A localization in intrinsic neurons is confirmed by a selective loss of glutamic acid decarboxylase after local injections of kainic acid. Peak concentrations of the enzyme occur near the pyramidal and granular cell bodies, corresponding to the site of the inhibitory basket cell terminals, and in the outer parts of the molecular layers. Some 85% of glutamic acid decarboxylase is situated in 'nerve ending particles'. Acetylcholine synthesis (by choline acetyltransferase) disappears after lesions of septo-hippocampal fibres. Since 80% of the hippocampal choline acetyltransferase is in 'nerve ending particles', the characteristic topographical distribution of this enzyme should reflect the distribution of cholinergic septo-hippocampal afferents. Serotonin, noradrenaline, dopamine and histamine are located/synthesized in afferent fibre systems. Some monoamine-containing afferents to the hippocampal formation pass via the septal area, others via the amygdala. The hippocampal formation also contains nerve elements reacting with antibodies against neuroactive peptides, such as enkephalin, substance P, somatostatin and gastrin/cholecystokinin.
 ...
PMID:Localization of putative transmitters in the hippocampal formation: with a note on the connections to septum and hypothalamus. 3 19

The administration of monosodium-L-glutamate (MSG) during the neonatal period is known to result in central nervous system lesions in the arcuate nucleus of the hypothalamus and the retina. Rodents so treated exhibit behavioral deficts and endocrinopathies including obesity, hypogonadism, hypothyroidism, pituitary atrophy, tail automutilation and diminished locomotor activity. Assessment of endocrine status revealed normal serum levels of glucagon, thyroid-stimulating hormone and luteinizing hormone, and diminished levels of thyroid hormones and growth hormone in MSG-treated rats. Prolactin levels were elevated in the glutamate-treated male rats. Within the brain hypothalamic levels of thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and somatostatin were unchanged. Measurement of neurotransmitters and neurotransmitter-related enzymes in individual hypothalamic nuclei derived from MSG-treated rats revealed normal levels of norepinephrine, serotonin and glutamic acid decarboxylase, but reduced levels of choline acetyltransferase and dopamine in the arcuate nucleus and median eminence. Histochemical methods for visualization of dopamine and acetylcholinesterase in the mediobasal hypothalamus confirmed these findings. The MSG-treated animals exhibited a normal diurnal rhythm of pineal serotonin N-acetyltransferase activity. These data indicate that the MSG-induced endocrine deficiency syndrome results at least partly from destruction of cholinergic and dopamingeric tuberoinfundibular systems in the hypothalamus.
 ...
PMID:Models of neuroendocrine regulation: use of monosodium glutamate as an investigational tool. 3 35

The differential vulnerability of basal forebrain cells to ibotenate (IBO) or quisqualate (QUIS) was investigated in rats. IBO was also coinjected with cystine (CYS) or zinc (Zn). Cortical choline acetyltransferase (ChAT) and glutamate decarboxylase (GAD) activity, neurotensin receptors, and high-affinity choline uptake sites were quantified in conjunction with radioimmunoassays for neurotensin, substance P, and somatostatin; immunocytochemistry for neurotensin-, somatostatin-, Leu-enkephalin-, and ChAT-positive cells; and in situ hybridization histochemistry of somatostatin, substance P, and enkephalin mRNAs. Compared with the performance of controls, continuous alternation performance in a T maze of IBO+Zn or IBO+CYS rats was better than that of IBO rats, whereas the performance of QUIS rats was unimpaired. Of those neurotransmitter systems examined, only ChAT-immunoreactive cells were vulnerable to IBO or QUIS. However, cholinergic cell loss did not correlate with impaired performance.
 ...
PMID:Basal forebrain neurons and memory: a biochemical, histological, and behavioral study of differential vulnerability to ibotenate and quisqualate. 128 13

The developmental regulation of cell proliferation, survival and cholinergic expression by growth hormone-releasing hormone (GHRH) and somatostatin (SRIF) was investigated in neuron-enriched cultures derived from 10-day-old embryonic chick spinal cord. In this study, 3H-thymidine in corporation into DNA was assessed, using two different applications, in order to determine both cellular proliferation and survival. The rate of neuroblast proliferation in both control and neuropeptide-treated cultures increased or remained the same up to day 6. However, in neuropeptide-treated cultures the magnitude of cell proliferation remained at levels higher than those observed in controls through day 6 and was most significant in SRIF-treated cultures at C4. In all groups, proliferation markedly declined by day 8. Survival of neuronal cells labelled at C4 remained high up to day 12 in all three groups, then drastically declined by day 17. Neuronal survival in the neuropeptide-treated cultures was also higher than in controls. Cholinergic expression, as assessed by activity of choline acetyltransferase (ChAT), responded differentially to neuropeptide treatment. Cultures treated with GHRH (100 nM) exhibited a long term significant enhancement in ChAT activity throughout the culture period, whereas those treated with SRIF (50 nM) expressed a transient decline in ChAT activity. Videometric analysis showed that both neuropeptides enhanced neuronal aggregation, neuritic arborization and neuritic length. These findings lead us to suggest that GHRH and SRIF may provide neurotrophic signals important not only for neuronal proliferation and survival but also for cholinergic neuronal expression. Furthermore, we propose that GHRH possesses specific cholinotrophic properties, whereas SRIF may act as a general neurotrophic factor.
 ...
PMID:Neuron-enriched cultures derived from spinal cord of 10-day-old chick embryos: influence of neuropeptides on neuronal survival, proliferation and cholinergic expression. 136 71

We examined the effects of ciliary neurotrophic factor (CNTF) and depolarization, two environmental signals that influence noradrenergic and cholinergic function, on neuropeptide expression by cultured sympathetic neurons. Sciatic nerve extract, a rich source of CNTF, increased levels of vasoactive intestinal peptide (VIP), substance P, and somatostatin severalfold while significantly reducing levels of neuropeptide Y (NPY). No change was observed in the levels of leu-enkephalin (L-Enk). These effects were abolished by immunoprecipitation of CNTF-like molecules from the extract with an antiserum raised against recombinant CNTF, and recombinant CNTF caused changes in neuropeptide levels similar to those of sciatic nerve extract. Alterations in neuropeptide levels by CNTF were dose-dependent, with maximal induction at concentrations of 5-25 ng/ml. Peptide levels were altered after only 3 days of CNTF exposure and continued to change for 14 days. Depolarization of sympathetic neuron cultures with elevated potassium elicited a different spectrum of effects; it increased VIP and NPY content but did not alter substance P, somatostatin, or L-Enk. Depolarization is known to block cholinergic induction in response to heart cell conditioned medium and we found that it blocked the induction of choline acetyltransferase (ChAT) and peptides by recombinant cholinergic differentiation factor/leukemia inhibitory factor (CDF/LIF). In contrast, it did not antagonize the effects of CNTF on either ChAT activity or neuropeptide expression. Thus, while CNTF has effects on neurotransmitter properties similar to those previously reported for CDF/LIF, the actions of these two factors are differentially modulated by depolarization, suggesting that the mechanisms of cholinergic and neuropeptide induction for the two factors differ. In addition, in contrast to CDF/LIF, CNTF did not alter levels of ChAT, VIP, substance P, or somatostatin in cultured dorsal root ganglion neurons. These observations indicate that CNTF and depolarization affect the expression of neuropeptides by sympathetic neurons and provide evidence for an overlapping yet distinct spectrum of actions of the two neuronal differentiation factors, CNTF and CDF/LIF.
 ...
PMID:Effects of ciliary neurotrophic factor (CNTF) and depolarization on neuropeptide expression in cultured sympathetic neurons. 137 70

Glutaminase has been considered to be a synthesizing enzyme of transmitter glutamate in pyramidal neurons of the cerebral cortex. In the present study, an attempt was made to examine with a double immunofluorescence method whether or not nonpyramidal neurons of the cerebral cortex are immunoreactive for glutaminase. Glutaminase was stained with mouse anti-glutaminase IgM and FITC-labeled anti-[mouse IgM] antibody. In the same section, parvalbumin (PA), calbindin (CB), choline acetyltransferase (CAT), vasoactive intestinal polypeptide (VIP), corticotropin releasing factor (CRF), cholecystokinin (CCK), somatostatin (SS), or neuropeptide Y (NPY) was visualized as a marker for nonpyramidal neurons with an antibody to each substance, biotinylated secondary antibody and Texas Red-labeled avidin. Virtually no glutaminase immunoreactivity was seen in PA-, CB-, CAT-, VIP-, CRF-, CCK-, SS-, or NPY-immunoreactive neuronal perikarya in the neocortex and mesocortex (cingulate and retrosplenial cortices), although it was detected in a few PA-, CB-, VIP-, CCK-, SS-, or NPY-immunoreactive nonpyramidal neurons in the piriform, entorhinal, and hippocampal cortices. PA- and CB-positive neurons have been reported to constitute the major population of GABAergic neurons in the cerebral cortex. Thus, the present results, together with the previous reports, suggest that most GABAergic, cholinergic and peptidergic nonpyramidal neurons in the neo- and mesocortex do not contain glutaminase.
 ...
PMID:Paucity of glutaminase-immunoreactive nonpyramidal neurons in the rat cerebral cortex. 138 31

The etiology of Alzheimer's disease (AD) is still unknown, and a definitive diagnosis of the disease can be determined only at autopsy or by brain biopsy. AD can be characterized by various structural changes, including cerebral cortical atrophy, neuronal loss, neuritic plaques, and neurofibrillary tangles. The primary defect involves reduced activity of choline acetyltransferase. Neurotransmitters, such as norepinephrine, serotonin, dopamine, and somatostatin, are also compromised. Treatment of AD requires maintenance of a consistent lifestyle and environment for the patient, as well as counseling and support for the patient's family. Medications, which have been effective in some patients, are primarily used to improve cognitive function and modify behavior. Cognitive medications such as tacrine hydrochloride and physostigmine have proven beneficial in some patients, while behavioral medications have been effective in the treatment of depression, aggression, agitation, and anxiety associated with AD. However, the side effect profile of each medication and its probable overall benefit to the individual patient should be evaluated before beginning therapy. Continued research in patients with AD is required to identify medications that will consistently ameliorate the memory loss associated with the disease.
 ...
PMID:Current concepts in the treatment of Alzheimer's disease. 157 22

We used rabbit antisera against manganese (Mn)-superoxide dismutase for immunohistochemical studies of localization in the rat neostriatum. Immunostaining was intense in large-sized neurons and several medium-sized neurons, but it was moderate to weak in other cells. Double immunostaining with monoclonal antibody to choline acetyltransferase or somatostatin demonstrated large-sized, Mn-SOD immunoreactive neurons to be cholinergic, and some medium-sized neurons which were intensely immunoreactive for Mn-SOD to contain somatostatinergic.
 ...
PMID:Localization of Mn-superoxide dismutase (Mn-SOD) in cholinergic and somatostatin-containing neurons in the rat neostriatum. 168 20

A detailed neurochemical analysis of the distribution of markers for the most relevant neurotransmitter systems within the rat hippocampal formation has been performed. The hippocampi, obtained from unfrozen brains of male Sprague-Dawley rats were subdissected into tissue parts containing mainly CA1, CA3 or the dentate gyrus, respectively. Each part was further divided into ventral and dorsal halves. In these six hippocampal subregions the concentrations of noradrenaline, dopamine, serotonin, 3-methoxy-4-hydroxyphenylglycol, 5-hydroxyindoleacetic acid and the putative neurotransmitter amino acids glutamate, aspartate, GABA, glycine and taurine, and the levels of somatostatin and neuropeptide Y and the activities of choline acetyltransferase, acetylcholinesterase and glutamate decarboxylase were measured. A marked heterogeneity in the subregional distribution of markers for various neurotransmitter systems within the hippocampal formation was observed. Each neuronal marker was characterized by an individual pattern of distribution. Most of the markers showed a concentration-gradient, increasing from dorsal to ventral; only taurine was more abundant in the dorsal than in the ventral parts and no dorsoventral difference was seen for aspartate, glycine and neuropeptide Y. The highest molar ratios of total 3-methoxy-4-hydroxyphenylglycol to noradrenaline and 5-hydroxyindoleacetic acid to serotonin were found in the dorsal hippocampus. The levels of noradrenaline, GABA and glutamate decarboxylase activity were highest in the dentate gyrus and lowest in CA1. The concentrations of somatostatin were highest in CA1; those of serotonin were highest in CA3. Highest activities of choline acetyltransferase and acetylcholinesterase were found in the dentate gyrus; lowest activities were found in CA3. In CA3 the lowest values of glutamate, aspartate, taurine and somatostatin were also found. The heterogeneity in the distribution of individual neurochemical markers allows insights into possible functional differences of hippocampal subregions and provides a relevant basis for future neurochemical investigations in this brain area.
 ...
PMID:Regional heterogeneity in the distribution of neurotransmitter markers in the rat hippocampus. 168 35

We have shown that the endogenous neuropeptides, growth hormone-releasing hormone (GHRH) and somatostatin (SRIF) influence expression of both cholinergic and catecholaminergic neuronal phenotypes in developing chick brain as assessed by the activities of choline acetyltransferase and tyrosine hydroxylase, respectively (Dev. Brain Res., 49 (1989) 275-280; Brain Research, 512 (1990) 297-303). In this study we examined the effects of GHRH and SRIF on GABAergic neuronal expression in ovo using activity of glutamate decarboxylase (GAD) as a neuronal marker. Chick embryos were administered GHRH or SRIF in ovo via the air sac on embryonic days 1, 3, 5 and 7, sacrificed at day 8 and the activity of GAD assayed in whole brain homogenates. GAD activity was significantly reduced in peptide-treated embryos as compared to controls. Similar results were obtained when GHRH was administered in a single dose at days 1 or 3 or when SRIF was administered in a single dose at day 3; GAD activity was significantly reduced as compared with control embryos. In contrast, embryos treated with either GHRH or SRIF on day 5 of development showed no difference in GAD activity as compared to controls. These data support our previous findings that endogenous neuropeptides such as GHRH and SRIF possess important properties with respect to neuronal phenotypic expression. They further define the critical period of sensitivity to these neuropeptides as 1-3 days of embryonic development.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Growth hormone-releasing hormone and somatostatin influence neuronal expression in developing chick brain. III. GABAergic neurons. 168 48


1 2 3 4 5 6 7 8 9 10 Next >>