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 effect of the opiate antagonists naloxone and MR2266 on ethanol-induced hypothermia and changes in Ca2+-stimulated Mg2+-ATPase activity in brain regions were investigated in the present study. Administration of different doses of ethanol (0.5-2 g/kg, IP) produced a dose-dependent hypothermia. Ca2+/Mg2+-ATPase activity in the hypothalamus was stimulated at 30 min and 2 hr after ethanol (2 g/kg, IP) treatment. In cortex, enzyme activity was inhibited by ethanol at 30 min with no change seen at 2 hr. Naloxone (7.5 mg/kg, SC) at a dose which did not affect body temperature or enzyme activity, partially inhibited ethanol-induced hypothermia and enzyme activity at the earliest time (30 min) but not at 2 hours. The opiate Kappa antagonist MR2266 (5 mg/kg, SC), however, significantly protected against ethanol hypothermia and enzyme activation measured at 30-120 min. This evidence suggests that ethanol-induced hypothermia and subsequent activation changes of Ca2+/Mg2+-ATPase in the hypothalamus may be regulated by opiate Kappa receptors, and that Ca2+ ions play an important role in mediating the effects of ethanol.
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PMID:Ethanol-induced hypothermia in rats: possible involvement of opiate kappa receptors. 301 66

This study examined the status of sarcolemmal Na+/K+-ATPase activity in rat heart under conditions of Ca2+-paradox to explore the existence of a relationship between changes in Na+/K+-pump function and myocardial Na+ as well as K+ content. One min of reperfusion with Ca2+ after 5 min of Ca2+-free perfusion reduced Na+/K+-ATPase activity in the isolated heart by 53% while Mg2+-ATPase, another sarcolemmal bound enzyme, retained 74% of its control activity. These changes in sarcolemmal ATPase activities were dependent on the duration and Ca2+ concentration of the initial perfusion and subsequent reperfusion periods; however, the Na+/K+-ATPase activity was consistently more depressed than Mg2+-ATPase activity under all conditions. The depression in both enzyme activities was associated with a reduction in Vmax without any changes in Km values. Low Na+ perfusion and hypothermia, which protect the isolated heart from the Ca2+-paradox, also prevented reperfusion-induced enzyme alterations. A significant relationship emerged upon comparison of the changes in myocardial Na+ and K+ content to Na+/K+-ATPase activity under identical conditions. At least 60% of the control enzyme activity was necessary to maintain normal cation gradients. Depression of the Na+/K+-ATPase activity by 60-65% resulted in a marked increase and decrease in intracellular Na+ and K+ content, respectively. These results suggest that changes in myocardial Na+ and K+ content during Ca2+-paradox are related to activity of the Na+/K+-pump; the impaired Na+/K+-ATPase activity may lead to augmentation of Ca2+-overload via an enhancement of the Na+/Ca2+-exchange system.
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PMID:Modification of heart sarcolemmal Na+/K+-ATPase activity during development of the calcium paradox. 1088 31