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Mammalian hibernators experience dramatic reductions in body temperature, metabolic rate, respiratory rate, and heart rate during hibernation. These changes are precisely controlled and reversible with only internally driven mechanisms, suggesting specific biochemical regulation. We present a model that integrates our observations of differential liver gene(More)
Six healthy adult males were fed four different diets to determine the effects of the quantity of fat (30% or 40% of energy as fat) and type of fat (polyunsaturated or saturated) on utilization of fatty acids. Each diet was fed for 15 d. The ratio of dietary polyunsaturated to saturated fat (P:S) was formulated at either 0.2 or 1.0 at both fat intakes.(More)
Endogenous opioids belonging to three opioid families were measured in different states of the hibernation cycle in brain of the Columbian ground squirrels. Using high-performance liquid chromatography-EC detection, the hypothalamic and septal concentrations of met-enkephalin were found to be significantly higher (p < 0.05) in the hibernating state than(More)
To localize and quantify the state-dependent changes in various opioid receptor subtypes in the limbic system of non-hibernating and hibernating Columbian ground squirrels, quantitative receptor-binding autoradiography was used. Compared to the non-hibernating animals, the binding density of [3H]-[D-Pen2,5]-enkephalin (DPDPE) to the delta receptor in the(More)
Even though the existence of the blood-borne "hibernation induction trigger" has been reported in the 13-lined ground squirrel, transfusion of plasma from hibernating rodents with other hibernating species as the recipients failed to induce the occurrence of summer hibernation. In order to verify whether the response to the "trigger" substance is species(More)
The Ca2+ uptake by isolated cardiac sarcoplasmic reticulum (SR) was compared between Richardson's ground squirrels and rats at 37, 25, 15, and 5 degrees C. The rate of SR Ca2+ uptake in ground squirrels was significantly higher than in rats over the temperature range. This marked species difference was observed over a Ca2+ concentration range from 0.1 to 10(More)
Dehydroevodiamine (DeHE) and evodiamine (EVO), alkaloids isolated from a Chinese medicinal herb, Wu-chu-yu, exhibit calcium antagonistic activity. Intraperitoneal injections of DeHE (5-20 mg/kg) and EVO (2.5-10 mg/kg) caused a dose-related hypothermia in afebrile rats at an ambient temperature (Ta) of 20 degrees C. Because the heat production of(More)
Acute systemic injection of ginseng saponin (GS) significantly elevated both the total and maximum heat production in young rats (3-6 months) and improved their cold tolerance under severe cold (-10 degrees C under helium-oxygen). However, pretreating the animal with the optimal dose (10 mg/kg) of GS devoid of Rg1 and Rb1 failed to elicit any beneficial(More)
To study the possible mechanism through which honokiol and magnolol elicit their central depressant effects, we examined the influence of these two phenolic compounds on 25 mM K(+)-stimulated release of [3H]acetylcholine (ACh) from the rat's hippocampal slices. Honokiol, but not magnolol, elicited a concentration-dependent enhancement of K+-evoked ACh(More)
Richardson's ground squirrels [body temperature (Tb) 7 degrees C] survive prolonged stable hypothermia for three times as long as do rats (Tb 19 degrees C) (72 vs. 24 h). We have examined the changes in blood gases and acid-base state to assess whether these contribute to this difference in survival time. None of the variables (measured at ambient(More)