Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The non-competitive N-methyl-D-aspartate (NMDA) antagonist, MK-801, has been reported to prevent or attenuate ischemic brain damage in various animal models. In halothane-anesthetized gerbils it was found that an optimal dose of MK-801 (3.0 mg/kg) for providing cerebral protection also produced hypothermia (31.1 +/- 0.62 degrees C) relative to control animals (34.2 +/- 0.77 degrees C, P less than 0.01). This degree of hypothermia alone was sufficient to provide complete histological and functional protection (spatial memory) against 5 min of carotid artery occlusion. In gerbils made ischemic, but maintained at normal body temperature, a dose of 3.0 mg/kg of MK-801 provided no protection against hippocampal cell loss or spatial memory impairment. These data suggest that the protective actions of MK-801 may be due entirely to drug-induced hypothermia.
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PMID:MK-801 reduced cerebral ischemic injury by inducing hypothermia. 216 11

Previous studies have demonstrated anterograde amnesia (AA) and its reversal in rats trained on passive avoidance tasks. The present investigation was conducted to determine whether induction and/or reversal of AA is limited to inhibitory learning tasks or whether these phenomena can be illustrated in behavioral situations involving choice. Accordingly, in Experiment 1, rats were trained on a T-maze escape task as either hypothermic (28 degrees C) or normothermic. Twenty-four hours later half of each acquisition group was tested as either hypothermic or normothermic. Results indicated a stern retention decrement for animals trained at a lower body temperature and tested as normothermic. However, this prograde memory deficit was attenuated when animals were recooled shortly prior to testing. In an attempt to extend the phenomenon of memory recovery observed in Experiment 1, Experiment 2 examined whether pretest injections of d-amphetamine (0.5 mg/kg), a purported amnesia-attenuating agent, could lessen the AA induced by hypothermia. Amphetamine, at least at the dose used, did not reduce the memory impairment. Results are interpreted in terms of the state dependent nature of memory.
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PMID:Hypothermia-induced anterograde amnesia and its reversal in rats trained on a T-maze escape task. 372 11

In ten patients we treated with distal arch aneurysms exposed through left posterolateral incisions, we induced profound hypothermia and circulatory arrest. Before circulatory arrest, thiopental, nicardipine and glycerol were used to protect the brain. The brain function was objectively evaluated through continuous recording of EEG and PO2 tension of the internal jugular vein. A cardiopulmonary bypass was introduced via the left atrium, pulmonary artery and left femoral artery cannulation. After proximal anastomosis between the graft and transverse aorta, graft cannulation was added. The distal aortic arch was replaced in all patients, with the entire descending thoracic aorta additionally replaced in two. No patients died in hospital. Two suffered neurological deficit, i.e., one having slight memory impairment and the other having a left-sided stroke due to right cerebral infarction, but recovering completely within a week. Our results indicate that profound hypothermia and circulatory arrest can be implemented safely when treating patients with distal arch aneurysm.
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PMID:[The treatment of patients with distal arch aneurysms--hypothermic circulatory arrest and left posterolateral exposure]. 759 44

We examined the effects of p.o. administered 3-[1-(phenylmethyl)-4-piperidinyl]-1-(2,3,4,5-tetrahydro-1H-1-b enzazepin-8- yl)-1-propanone fumarate (TAK-147), a novel AChE inhibitor, on impaired learning and memory in animal models. At 1 to 3 mg/kg, TAK-147 ameliorated the passive avoidance deficit induced by diazepam. TAK-147 did not affect delayed-matching-to-position (DMTP) performance of normal rats at doses of 1 to 30 mg/kg assessed by using a three-lever operant chamber, but 9-amino-tetrahydroacridine disrupted the DMTP response at 5 to 20 mg/kg. Scopolamine (0.02-0.1 mg/kg s.c.) impaired DMTP performance, whereas methylscopolamine did not affect the DMTP task. TAK-147 ameliorated the impairment of DMTP performance induced by scopolamine without affecting the general behavior of the rats; however, 9-amino-tetrahydroacridine produced no significant amelioration of the impairment. The intraventricular injection of AF64A disrupted differential-reinforcement-of-low-rate 10-sec performance in rats, as demonstrated by marked decreases in reinforcement rate and response efficiency. TAK-147 slightly increased the reinforcement rate in AF64A-treated rats at a low dose of 1 mg/kg, but the effect was not significant statistically. TAK-147 had no significant effect on the duration of immobility in rats in a forced swimming test at doses of 2 to 10 mg/kg. 9-Amino-tetrahydroacridine prolonged the duration of immobility at 5 to 20 mg/kg. Furthermore, TAK-147 reversed reserpine-induced hypothermia and ptosis in mice at doses of 3 to 10 mg/kg, a result that implies an antidepressant-like action. These results indicate that TAK-147 ameliorates learning and memory impairment in animal models without affecting the general behavior or causing behavioral depression and suggest that TAK-147 may be useful for the treatment of Alzheimer's disease.
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PMID:Effects of 3-[1-(phenylmethyl)-4-piperidinyl]-1-(2,3,4,5-tetrahydro-1 -H-1-benzazepin-8-yl)-1-propanone fumarate (TAK-147), a novel acetylcholinesterase inhibitor, on impaired learning and memory in animal models. 866 90

The pharmacological properties of MKC-231 (2-(2-oxopyrrolidin-1-yl)-N- (2,3-dimethyl-5,6,7,8-tetrahydrofuro[2,3-b]quinolin-4-yl) acetoamide, CAS 135463-81-9) in comparison with an acetylcholinesterase (AChE) inhibitor, tacrine (CAS 1684-40-8) were studied. MKC-231(10(-10)-10(-6) moll) significantly increased high affinity choline uptake (HACU) when it was incubated with the hippocampal synaptosomes of ethylcholine mustard aziridinium ion (AF64A) treated rats, but not of normal rats. MKC-231 did not affect the AChE activity, [3H]- quinuclidinyl benzilate binding, and [3H]-pirenzepine binding. Oral administration of MKC-231 (1-10 mg/kg) significantly improved the learning deficits in the Morris' water maze of AF64A-treated rats, but it did not produce any significant side effects, like tremor, salivation or hypothermia, which were observed in rats treated with high doses of tacrine. Tacrine (0.1-3 mg/kg p.o.) failed to ameliorate the learning deficits in AF64A-treated rats. These results suggest that MKC-231 is a novel and quite unique compound, which improves the memory impairment induced by AF64A through the enhancement of HACU without any side effects at the effective doses.
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PMID:Effect of the novel high affinity choline uptake enhancer 2-(2-oxopyrrolidin-1-yl)-N-(2,3-dimethyl-5,6,7,8-tetrahydrofuro[2,3-b] quinolin-4-yl)acetoamide on deficits of water maze learning in rats. 874 80

Taltirelin hydrate[1-methyl-(S)-4,5-dihydroorotyl-L-histidyl-L-prolineamide tetrahydrate] is a new orally active thyrotropin releasing hormone (TRH) peptide analog synthetized from aspartic acid. From preclinical studies with mice and rats, Taltirelin hydrate was found to be highly stable in the blood and brain as compared with TRH. Furthermore, the CNS stimulating actions of Taltirelin hydrate such as antagonistic actions against pentobarbital-induced anesthesia and reserpine- induced hypothermia were found to be about 100 times stronger and about 8 times longer-lasting as compared with those of TRH. Meanwhile, the affinity of Taltirelin hydrate for TRH-receptors was about 10 times lower, and the endocrine action was about 5 times less potent than those of TRH. Therefore, high CNS-selectivity and long-lasting action of Taltirelin hydrate would be attributed to its high stability in the body and low affinity for TRH-receptors. Oral administrations of Taltirelin hydrate ameliorated consiousness impairment, memory impairment and motor dysfunction in several models. The clinical studies for patients with spinocerebellar degeneration are in progress.
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PMID:[Synthesis and pharmacological action of TRH analog peptide (Taltirelin)]. 950 2

GABA(B) (gamma-aminobutyric acid type B) receptors are important for keeping neuronal excitability under control. Cloned GABA(B) receptors do not show the expected pharmacological diversity of native receptors and it is unknown whether they contribute to pre- as well as postsynaptic functions. Here, we demonstrate that Balb/c mice lacking the GABA(B(1)) subunit are viable, exhibit spontaneous seizures, hyperalgesia, hyperlocomotor activity, and memory impairment. Upon GABA(B) agonist application, null mutant mice show neither the typical muscle relaxation, hypothermia, or delta EEG waves. These behavioral findings are paralleled by a loss of all biochemical and electrophysiological GABA(B) responses in null mutant mice. This demonstrates that GABA(B(1)) is an essential component of pre- and postsynaptic GABA(B) receptors and casts doubt on the existence of proposed receptor subtypes.
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PMID:Epilepsy, hyperalgesia, impaired memory, and loss of pre- and postsynaptic GABA(B) responses in mice lacking GABA(B(1)). 1149 50

Nicotine and ethanol are the most widely abused drugs in the world. They are very often used and abused together. However, little is known about the functional interaction of nicotine and ethanol. The current project studied the interactive effects of nicotine and ethanol on working memory in the eight-arm radial maze. Adult female rats were trained on a radial arm maze for 18 sessions to reach asymptotic levels of choice accuracy. During the maintenance phase of radial arm maze testing, which indexed working memory function, the rats were injected with nicotine (0, 0.15, 0.3, 0.6, and 1.2 mg/kg sc, 20 min before testing) with and without ethanol pretreatment (0 or 1.5 g/kg, 16% v/v ip, 30 min before testing). All animals received the treatments in a counterbalanced order with at least 1 week between treatments. Higher doses of nicotine had a significant interaction with ethanol in terms of radial arm maze choice accuracy. Nicotine plus ethanol coadministration precipitated a significant choice accuracy impairment at doses that when given alone had no effect on performance. At the lower dose range of nicotine, ethanol coadministration eliminated the nicotine-induced memory improvement. No significant effects were seen with either nicotine or ethanol treatment or their interaction on response latency in the radial arm maze. The nicotine-ethanol interactive effects on memory were compared with the interaction of their well-characterized hypothermic effects. Nicotine and alcohol, when injected separately or in combination, induced hypothermia with no significant interactive effect. This study found that ethanol blocked low-dose nicotine-induced memory improvement and precipitated memory impairment with high-dose nicotine treatment. This interaction may be an important consideration for nicotine and ethanol coabuse and the possible therapeutic use of nicotinic drugs for memory dysfunction.
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PMID:Nicotine-alcohol interactions and cognitive function in rats. 1206 76

It is firmly established that the hippocampus, a brain region implicated in spatial learning, episodic memory, and consolidation, contains a high concentration of CB(1) receptors. Moreover, systemic and intrahippocampal administration of cannabinoid agonists have been shown to impair hippocampal-dependent memory tasks. However, the degree to which CB(1) receptors in the hippocampus play a specific functional role in the memory disruptive effects of marijuana or its primary psychoactive constituent Delta(9)-tetrahydrocannabinol (Delta(9)-THC) is unknown. This study was designed to determine whether hippocampal CB(1) receptors play a functional role in the memory disruptive effects of systemically administered cannabinoids, using the radial arm maze, a well characterized rodent model of working memory. Male Sprague-Dawley rats were implanted with bilateral cannulae aimed at the CA1 region of the dorsal hippocampus. The CB(1) receptor antagonist, rimonabant, was delivered into the hippocampus before to a systemic injection of either Delta(9)-THC or the potent cannabinoid analog, CP-55,940. Strikingly, intrahippocampal administration of rimonabant completely attenuated the memory disruptive effects of both cannabinoids in the radial arm maze task, but did not affect other pharmacological properties of cannabinoids, as assessed in the tetrad assay (that is, hypomotility, analgesia, catalepsy, and hypothermia). Infusions of rimonabant just dorsal or ventral to the hippocampus did not prevent Delta(9)-THC-induced memory impairment, indicating that its effects on mnemonic function were regionally selective. These findings provide compelling evidence in support of the view that hippocampal CB(1) receptors play a necessary role in the memory disruptive effects of marijuana.
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PMID:Hippocampal CB(1) receptors mediate the memory impairing effects of Delta(9)-tetrahydrocannabinol. 1932 69

Aging is a consequence of progressive decline in special and somatosensory functions and specific brain stem nuclei. Many senescent stigmata, including hypoxia, hypoxemia, depressed cerebral blood flow and glucose metabolism, diseases of senescence, and their medications all enhance hypothermia as do alcohol, cold environment, and malnutrition. Hypothermia is a critical factor having deleterious impact on brain stem and neocortical functions. Additionally, anesthesia in elderly also promotes hypothermia; anesthetics not only cause consciousness (sensory and motor) changes, but memory impairment as well. Anesthesia inhibits cholinergic pathways, reticular and thalamocortical systems, cortico-cortical connectivity, and causes post-operative delirium and cognitive dysfunction. Increasing evidence indicates that anesthetic exposures may contribute to dementia onset and Alzheimer's disease (AD) in hypothermic elderly. Inhaled anesthetics potentiate caspases, BACE, tau hyperphosphorylation, and apoptosis. This paper addresses the important question: "Why do only some elderly fall victim to AD"? Based on information on the pathogenesis of early stages of cognitive dysfunction in elderly (i.e., due to senescent stigmata), and the effects of anesthesia superimposed, a detailed plausible neuropathological substrate (mechanism/pathway) is delineated here that reveals the possible cause(s) of AD. Basically, it encompasses several risk factors for cognitive dysfunction during senescence plus several hypothermia-enhancing routes; they all converge and tip the balance towards dementia onset. This knowledge of the confluence of heterogeneous risk factors in perpetuating dementia relentlessly is of importance in order to: (a) avoid their convergence; (b) take measures to stop/reverse cognitive dysfunction; and (c) to develop therapeutic strategies to enhance cognitive function and attenuate AD.
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PMID:Conversion of elderly to Alzheimer's dementia: role of confluence of hypothermia and senescent stigmata--the plausible pathway. 2150 31


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