Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TRH and a new TRH analog (all L-pyro-2-aminoadipyl-histidyl-thiazolidine-4-carboxamide, MK-771) have been compared with several other peptides for their "analeptic" activity and their ability to enhance the excitatory actions of microiontophoretically applied acetylcholine (ACh) on cerebral cortical neurons of rats. TRH and MK-771 offset the narcosis induced by pentobarbital in mice, whereas the C-terminal free acid derived from TRH, melanostatin, somatostatin and pyroglutamyl-histidineamide have been found inactive. Similarly, of these peptides only TRH and MK-771 induced a tremor of the forepaws in pentobarbital-anesthetized mice. Employing comparable ejection currents and durations, only TRH and MK-771, applied by microiontophoresis, enhanced the excitatory actions of ACh on spontaneously active cortical neurons in anesthetized rats. Based on these findings and other recent data, it is suggested that the interactions of TRH and MK-771 with cholinergic mechanisms may underlie some of the actions, including their anti-anesthetic effects, of these peptides.
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PMID:Studies on the neuropharmacology of thyrotropin releasing hormone (TRH) and a new TRH analog. 41 61

Galanin has been reported to stimulate secretion of GH in humans and rats. Thus, to investigate whether the effect of galanin on GH release is the result of either a stimulation of GH-releasing factor (GRF) and/or an inhibition of somatostatin (SRIF) release, we have evaluated the action of galanin on the release of SRIF and GRF from median eminence (ME) fragments in vitro. The MEs from adult male rats were incubated in Krebs-Ringer bicarbonate-glucose buffer, pH 7.4, at 37 degrees C, in an atmosphere of 95% O2, 5% CO2 with constant shaking for 30 min. Medium was discarded and replaced by medium containing various concentrations of galanin (10(-10)-10(-7) M). Galanin stimulated SRIF and GRF release in a dose-related manner. This effect was significant at concentrations varying from 10(-8) to 10(-7) M. To determine the mechanism by which galanin stimulated SRIF and GRF release, MEs were incubated with pimozide (dopaminergic blocker), phentolamine (alpha-adrenergic blocker) or naloxone (opioid blocker), at concentrations of 10(-6) M, and the effect of galanin was then evaluated. Phentolamine and naloxone did not alter the stimulatory effect of galanin, but when galanin was tested with pimozide, the galanin-induced release of SRIF and GRF was blocked. To determine whether the effect of galanin is mediated through D-1 and/or D-2 dopamine receptors, selective antagonists of D-1 (SCH 23390) and D-2 receptors (domperidone) were used (10(-7) M) in the presence of galanin (10(-7) M).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of galanin on growth hormone-releasing factor and somatostatin release from median eminence fragments in vitro. 128 34

In 38 old aged parkinsonian patients, two major subgroups could be established: one with predominant akinesia, rigidity, postural instability and accompanying cognitive impairment with intellectual deterioration correlated with duration of disease but not with age of onset and another with predominant tremor and relatively intact intellectual functions. The mean somatostatin-like immunoreactivity (SLI) level in the cerebrospinal fluid (CSF) was significantly lower in parkinsonian patients (21.4 +/- 8.1 fmol ml-1) compared to senile control patients (29.5 +/- 9.4 fmol ml-1). In contrast to senile dementia of Alzheimer's type SLI was not correlated with dementia scores but with motor disease progression. Homovanillic acid (HVA) significantly decreased only in patients without L-DOPA treatment. Correlations between SLI, HVA and 5-hydroxyindole acetic acid (5-HIAA) indicate a degeneration of multiple neuronal networks which includes somatostatinergic neurons.
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PMID:Parkinson's disease and dementia: clinical and neurochemical correlations. 137 66

Substance P-like and somatostatin-like immunoreactivities (SPLI and SLI) were determined in ventricular fluid of patients with chronic pain syndromes and in a comparison group with multiple sclerosis, essential tremor, epilepsy and postanoxic myoclonus. Concentrations of SPLI and SLI were non-significantly decreased by 40% and 33% in chronic pain patients as compared with control patients without pain. There were no differences apparent between subgroups of pain patients (deafferentation pain, neoplasia-induced pain, thalamic pain). High pressure liquid chromatography combined with radioimmunoassay showed marked heterogeneity of SPLI and SLI.
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PMID:Substance P-like immunoreactivity and somatostatin-like immunoreactivity in the ventricular fluid of patients with chronic pain syndromes. 183 80

The influence of alpha-melanocyte stimulating hormone (alpha-MSH) and beta-endorphin (beta-END) on the secretion of somatostatin (SRIF) from the median eminence (ME) was studied using an in vitro incubation system. The MEs from adult male rats were first preincubated at 37 degrees C for 30 min with constant shaking in 0.4 ml of Krebs-Ringer bicarbonate-glucose buffer (pH 7.4) containing bacitracin in an atmosphere of 95% O2/5% CO2. Medium was discarded and replaced by medium containing different doses of alpha-MSH, beta-END, or a fixed dose of alpha-MSH (10(-7) M or 10(-9) M) plus beta-END at various concentrations. By themselves alpha-MSH and beta-END did not alter basal SRIF release, but in the presence of alpha-MSH (10(-7) M) beta-END stimulated somatostatin release. This effect was significant at concentrations of beta-END of 10(-8) M and higher. The permissive effect of alpha-MSH was observed at a concentration as low as 10(-9) M, but in this case the stimulatory effect of beta-END became evident only at higher doses tested (10(-7) M). It is suggested that alpha-MSH and beta-END participate in the modulation of SRIF release. By themselves beta-END and alpha-MSH did not affect basal release of SRIF but in the presence of alpha-MSH, beta-END had a stimulatory effect on SRIF release. The mechanism for this interaction is unknown. The results are consistent with the possibility that beta-END neurons have stimulatory and inhibitory effects on SRIF release and that alpha-MSH, by blocking the inhibitory components, discloses the stimulatory effect of beta-END on SRIF release.
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PMID:Alpha-melanocyte stimulating hormone discloses a stimulatory effect of beta-endorphin on somatostatin release. 288 55

Experiments were performed in vitro to examine the possible role of calcium and calmodulin in GRF-induced somatostatin (SRIF) release from the median eminence. Adult male rats were used as tissue donors. The median eminences were first prestimulated in 0.4 ml Krebs Ringer bicarbonate glucose buffer (pH 7.4) containing bacitracin at 37C in an atmosphere of 95% O2, 5% CO2 with constant shaking for 30 min. When calcium was omitted, this medium was used during the prestimulation and stimulation periods. After prestimulation, the medium was discarded and replaced by medium containing the different substances to be tested (GRF, EGTA, calcium channel blockers, and calmodulin inhibitors). The stimulation of SRIF release induced by 10(-10) M GRF was not inhibited by omission of extracellular calcium or when the remaining CA+2 was chelated with 10(-4) M EGTA. The calcium channel blockers, nifendipine and verapamil (10(-6) M), failed to alter the increase of SRIF release induced by rGRF. Three calmodulin inhibitors were employed to examine the possible influence of calmodulin on GRF-induced SRIF release. Trifluoperazine (10(-6) M), triflupromazine (10(-6) M) and penfluridol (10(-7) M) had an inhibitory effect on the stimulation of SRIF release induced by GRF and failed to alter resting release. Thus, GRF can evoke SRIF release independently of extraterminal Ca+2 concentration and Ca+2 influx into the nerve terminals, but the releasing process involves translocation of Ca+2 from intracellular stores. The inhibitory effect of the calmodulin inhibitors on GRF-induced SRIF release, suggests that the translocated Ca+2 must bind to calmodulin in order to release SRIF.
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PMID:Calmodulin dependence of somatostatin release stimulated by growth hormone-releasing factor. 289 60

The effects of a wide range of doses of systemically administered cysteamine were studied on locomotor behavior, passive avoidance memory, cortical and cerebrospinal fluid somatostatin-like immunoactivity and cortical levels of dopamine and norepinephrine. High doses of cysteamine (200 and 250 mg/kg s.c.) led to sustained locomotor activation. Doses of 150 mg/kg and above resulted in head and neck tremor and increased defecation. When cysteamine was administered immediately following the acquisition of a passive avoidance response, doses of 50 mg/kg and above resulted in significant attenuation of passive avoidance retention test performance. Cysteamine in doses of 50 mg/kg and above depleted cortical somatostatin-like immunoactivity by approximately 50%. The depletion of cortical somatostatin-like immunoactivity was accompanied by a rapid rise in somatostatin-like immunoactivity in cerebrospinal fluid. In addition to the depletion of somatostatin-like immunoactivity, high doses of cysteamine (150 mg/kg and above) produced changes in cortical levels of norepinephrine and dopamine, reminiscent of dopamine-beta-hydroxylase inhibition. The results of this series of experiments suggest that somatostatin, in addition to its effects on hormonal regulation, may play an important role in behavior and passive avoidance learning and memory. It is possible that the amnesia produced by cysteamine may have been due to the release of somatostatin into CSF from tissue stores, rather than somatostatin depletion per se. It is also possible that the catecholaminergic effects of high doses of cysteamine contribute to the behavioral deficits observed.
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PMID:Cysteamine-induced depletion of central somatostatin-like immunoactivity: effects on behavior, learning, memory and brain neurochemistry. 382 20

It has recently been demonstrated that human pancreatic GH-releasing factor (hpGRF-44) and Tyr-D-Trp-Ala-Trp-D-Phe-NH2 (subsequently referred to as 'the peptide') release GH from rat pituitary glands maintained in vitro and, in the former case, increase circulating GH in rats and man. The commercial importance of discovering an agent capable of specifically enhancing GH secretion in ruminants stimulated the present study which examined: the intravenous administration of both peptides on plasma GH, prolactin, insulin, glucose, urea and non-esterified fatty acids in goats and the effect of the peptide on the release of GH from sheep pituitary glands maintained in vitro. The peptide was injected into the jugular vein of goats in three different forms and at several concentrations (dispersal by shaking, 0.07 microgram/kg; 0.7 microgram/kg; ball-milled, 7.0 micrograms/kg, 70 micrograms/kg; dimethyl sulphoxide (5%), 7.0 micrograms/kg, 70 micrograms/kg). None of the treatments stimulated a significant increase in circulating GH. Nevertheless the peptide (20 micrograms/ml medium) was found to stimulate a 50-60% increase in the production of GH from sheep pituitary glands maintained in vitro. The effect of intravenously injecting hpGRF-44 (1.0 microgram/kg) was investigated in the present and absence of passive immunization with sheep anti-somatostatin immunoglobulin G (IgG) (a bolus of 600 mg, 3 h before treatment with hpGRF-44). Plasma GH was increased (P less than 0.001) within 15 min of treatment and the magnitude of the response was the same for both the immunized and non-immunized goats. A second peak was measured after approximately 75 min which was only significant (P less than 0.05) in the immunized group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of intravenous administration of growth hormone-releasing factor (hpGRF-44) and Tyr-D-Trp-Ala-Trp-D-Phe-NH2 on plasma hormones and metabolites in goats. 643 24

Immunoreactive- (IR-) somatostatin (SRIF), neuropeptide Y (NPY) and corticotropin-releasing factor (CRF) contents were investigated in the brain of tremor rats with absence-like seizure and spontaneously epileptic rats (SER), which is a genetically defined double-mutant (zi/zi, tm/tm) obtained by mating zitter homozygote (zi/zi) with tremor heterozygote (tm/+) and shows both absence-like seizure and tonic convulsions. Increased levels of IR-NPY and IR-CRF were observed in several regions including the amygdala and hippocampus in homozygous SER compared to heterozygous SER (zi/zi, tm/+ or +/+). Homozygous tremor rats (tm/tm) showed lower levels of IR-NPY and IR-CRF contents mainly in the hippocampus and mesolimbic system (entorhinal and pyriform cortex and nucleus accumbens) than heterozygous tremor rats. IR-SRIF contents of homozygous SER were higher in frontal cortex than heterozygous SER and in amygdala than homozygous tremor rats. No change of IR-SRIF between groups was noted in the hippocampus among brain structures underlying epileptogenicity. The results suggest that the change of neuropeptide levels, most conspicuous in NPY among three peptides tested, may be involved in the phenotypical manifestation of seizures in SER and tremor rats, and that the development of tonic convulsion and absence seizures may be differently associated with the change of brain neuropeptide levels.
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PMID:Altered brain contents of neuropeptides in spontaneously epileptic rats (SER) and tremor rats with absence seizures. 762 20

Somatostatin analogues are potent growth hormone and glucagon inhibitors and are commonly used in the treatment of several endocrine and non-endocrine disorders. We report severe and longstanding hypoglycemia triggered by long-acting octreotide (Sandostatin LAR) in a 62-year-old women with malignant mesenchymal tumor. Hypoglycemia developed after 6 hours of octreotide injection and she was admitted to the emergency unit with sweating, tremor, palpitation and confusion. On admission, her plasma glucose level was: 17 mg/dl (normal: 65-110), cortisol: 31 microg/dl (normal: 5-25), insulin: 4.32 microIU/ml (normal: 6-27), C-peptide: 2.64 ng/ml (normal: 0.9-4.0), growth hormone: 0.06 ng/ml (normal: 0.06-5.0), insulin-like growth factor-I: 8.5 ng/ml (normal: 101-303), insulin-like growth factor binding protein-3: 1715 ng/ml (normal: 2020-3990). Intravenous dextrose infusion was given for a month to sustain normoglycemia since hypoglycemia recurred following cessation of infusion. Therefore, prednisolone, 35 mg/day was added and the parenteral dextrose infusion rate was decreased gradually and finally stopped. Normoglycemia could be maintained with prednisolone 20 mg/day. In patients prone to tumor hypoglycemia, long-acting octreotide may trigger severe and prolonged hypoglycemia due to suppression of counter-regulatory hormones; clinical trial with short-acting octreotide may be warranted to predict and prevent this life-threating complication.
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PMID:Severe and prolonged hypoglycemia triggered by long-acting octreotide in a patient with malignant mesenchymal tumor: case report. 1267 21


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