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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Central injections of bombesin have been shown to produce hypothermia in animals exposed to a cold environment, but not in animals maintained under thermoneutral conditions. Peripheral injections have been associated with decreased food intake in rats. The data reported here demonstrate a significant, dose-related decrease in both body temperature and food intake following microinjections of bombesin into the cerebral ventricles of male rats maintained at reduced body weight. All measurements of food intake and body temperature were recorded at an ambient temperature of 23 +/- 1 degrees C. The bombesin-induced hypothermia, but not the hypophagia, was partially reversed by prior subcutaneous injections of naloxone. Microinjections of bombesin failed to produce a decrease in body temperature in satiated rats.
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PMID:The effects of injections of bombesin into the cerebral ventricles on food intake and body temperature in food-deprived rats. 714 34

Intraventricular administration of the neuropeptide, bombesin, to intact and sham-pinealectomized fish significantly decreased their behaviorally selected internal body temperatures in horizontal thermal gradients. A behavioral hypothermia of 4-7 degrees C was evident regardless of the previous acclimatization temperature (10 or 25 degrees C) and preferred body temperatures selected by individual fish. Pinealectomy increased the body temperatures of all control fish by 2-4 degrees C while markedly reducing the hypothermic effects of administration of bombesin. The hypothermic effects of bombesin were most evident in the pinealectomized fish acclimatized to 10 degrees C. The possible relations between neuropeptides and the pineal gland in the regulation of body temperature are considered.
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PMID:Pinealectomy modifies the thermoregulatory effects of bombesin in goldfish. 717 41

The effect of ambient temperature (Ta) on the rectal temperature (Tre) response to intraventricular injection of bombesin has been evaluated in conscious adult male rats. At Ta = 4 degrees C, bombesin (50 ng-1 microgram) caused a marked hypothermia which was dose-dependent both in terms of the magnitude and of the duration of the response. The bombesin-induced hypothermia was reduced at Ta = 24 degrees C, whereas at Ta = 31 or 33 degrees C, the peptide (1 microgram) failed to affect Tre.AtTa = 36 degrees C, bombesin 1-10 micrograms induced an elevation in Tre. The hyperthermia observed at high Ta could be reversed to hypothermia by transferring rats to cold. The analogs [d-Trp8]bombesin or [d-Leu13]bombesin, tested under the same conditions, failed to produce significant changes in Tre. These findings demonstrate that bombesin appears to act in the brain as a poikilothermic agent by disrupting thermoregulation at temperatures below or above thermoneutrality.
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PMID:Bombesin-induced poikilothermy in rats. 737 Jul 72

Rats infused centrally with bombesin become hypothermic at normal ambient temperatures when acutely deprived of food, but not while allowed unrestrained access to food. Ad lib-fed rats, tested at normal ambient temperatures, become hypothermic after receiving intracerebroventricular (ICV) bombesin when they have ventromedial hypothalamic lesions or when administered insulin or 2-deoxy-D-glucose peripherally. All of these conditions have been linked to reductions of sympathetic nervous system activity to brown adipose tissue (BAT), a major thermogenic mechanism of many homeotherms. A between group design was used to examine the effects of ICV bombesin infusions on the response to peripheral injections of a) the sympathetic ganglionic blocker chlorisondamine (2.5 mg/kg, IP) in ad lib-fed rats, b) the nonspecific beta-agonist isoproterenol (30 mg/kg, IP) in food-deprived rats, and c) the combination of isoproterenol and chlorisondamine in ad lib-fed rats. Ad lib-fed rats receiving ICV bombesin (100 ng/5 microliters), in combination with peripheral chlorisondamine injection, became hypothermic 60 min postbombesin administration (-2.84 +/- 0.33 degrees C), while ad lib-fed rats receiving ICV bombesin infusion and peripheral injections of saline did not (-0.08 +/- 0.37 degrees C). Isoproterenol blocked hyperthermia in ad lib-fed rats injected with chlorisondamine and ICV bombesin. Food-derived rats receiving ICV bombesin infusion and peripheral saline injection exhibited hypothermia 60 min postbombesin administration (-2.51 +/- 0.29 degrees C). Peripheral injections of isoproterenol prevented bombesin-induced hypothermia in food-deprived rats. These data suggest that bombesin induces hypothermia at normal ambient temperatures when the sympathetic nervous system drive to BAT cannot be (or is not) activated.
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PMID:Bombesin-induced hypothermia in rats tested at normal ambient temperatures: contribution of the sympathetic nervous system. 760 92

Neuromedin B (NMB) and neuromedin C (NMC) are peptides found in the mammalian central nervous system, and their concentrations are particularly high in the hypothalamus. The amino acid sequences of these peptides are similar to that of bombesin, which is known to induce marked hypothermia not only in amphibians but also in mammals. The effect of neuromedins and related peptides on the body temperature regulation was examined in the rat under a thermoneutral environment. The findings indicated that NMC caused moderate hypothermia following intracerebroventricular administration, while the effect of NMB was meager, suggesting that these two neuropeptides possess different physiological functions in the brain.
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PMID:Effects of neuromedins and related peptides on the body temperature of rats. 765 Aug 56

The effect of centrally administered bombesin on core temperature was investigated in rats which had been chronically fitted with a cannula in the third cerebral ventricle and with an intraperitoneal temperature-monitoring radiotransmitter. Intracerebroventricularly administered bombesin (0.01, 0.1 or 1 microgram) resulted in hypothermia, the duration and depth of the effect being a function of the dose. The use of telemetry minimized experimental interventions in this study; the results demonstrate that the hypothermic response to bombesin is not dependent upon exposure to a low ambient temperature, food restriction or insulin treatment as suggested by previous studies involving measurement of core temperature by a rectal probe.
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PMID:Effect of bombesin on core temperature in rats: studies involving radiotelemetry. 801 60

Hypothermia induced by administration of bombesin into the lateral ventricle of brain in cold exposed rats could be inhibited by Guizhi Tang (GZT). The GZT could also reverse the potency of fever induced by injection of [D-Phe12] bombesin, a bombesin receptor antagonist, into the brain of febrile rats. But there was no effect of GZT on body temperature when bombesin and [D-Phe12] bombesin were simultaneously injected into the lateral ventricle of cold exposed rats. These studies indicated that the dual-directional thermoregulation of GZT was carried out partially by affecting the bombesin receptor in thermoregulation center of hypothalamus.
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PMID:[Mechanism of decoction of guizhi tang on dual-directional thermoregulation. Effect on the action of bombesin]. 804 20

Microinfusion of bombesin into the lateral ventricles (LV) of rats pretreated with insulin or acutely deprived of food has been demonstrated to reduce core body temperature. Lesions of the ventromedial hypothalamus (VMH) have been shown to produce hyperphagia, hyperinsulinemia, and to alter serum metabolic fuels. The present study examines VMH lesions as a permissive event in bombesin-induced hypothermia in rats tested at normal ambient temperature. A between-group design was used to evaluate the effect of microinjections of bombesin (1, 10, 100 ng) into the LV of rats with bilateral VMH lesions or sham lesions. Core body temperature was recorded over a 240-min period. In animals with lesions of the VMH, hypothermia was demonstrated by 30 min after injection of the 10 ng and 100 ng doses; the hypothermia persisted for 120 min. The 1 ng dose had no effect on body temperature in VMH-lesioned animals. Animals that received sham lesions of the VMH did not demonstrate a reduction in core body temperature at the maximum effective dose (100 ng) of bombesin. These results suggest that some event(s) associated with bilateral VMH lesions acts as a permissive factor in the production of bombesin-induced hypothermia at normal ambient temperature.
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PMID:Bombesin-induced hypothermia in VMH-lesioned rats. 822 Nov 61

Gastrin-releasing peptide (GRP) is a mammalian bombesin-like peptide which is widely distributed in the central nervous system as well as in the gastrointestinal tract. GRP binds to its high affinity receptor (GRPR) to elicit a wide spectrum of biological effects on behavior, digestion, and metabolism. To define the in vivo function of GRPR, we generated GRPR null mutant mice by gene targeting. The intracerebroventricular administration of GRP caused hypothermia in wild-type mice, but not in mutant mice. The GRPR deficient mice showed significantly increased locomotor activity during the dark period, and social responses scored by sniffing, mounting, and approaching behaviors against an intruder. Aggressive scores such as fighting and biting were not altered in the mutant mice. These phenotypes were observed in mice generated from two independent ES cell clones and backcrossed to a C57BL/6J background. The GRPR deficient mice should be useful for studying the bombesin system in vivo.
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PMID:Generation and characterization of mice lacking gastrin-releasing peptide receptor. 934 64

Bombesin is a member of a class of neuroactive chemicals that have potent thermoregulatory effects in ectothermic and endothermic vertebrate species. Bombesin-like peptides are found in the brains of ectothermic and endothermic vertebrates and have been implicated in the central nervous system modulation of behavioral thermoregulation. Amphibians rely on behavioral thermoregulation to maintain their body temperature within developmental stage-dependent critical limits. To investigate the influence of bombesin on behavioral thermoregulation, we examined the effects of central injections of bombesin on thermal habitat selection at different stages of bullfrog development. Tadpoles and adult male and female frogs were allowed to select a preferred temperature, within an aquatic thermal gradient, before and after receiving an intracerebroventricular injection of bombesin. In larval and adult female bullfrogs, bombesin administration caused a decrease in preferred temperature values. This effect was clearly dose-dependent in tadpoles. Bombesin effects were variable in adult males, probably due to an overriding stress response to handling exhibited by males. The bombesin-induced hypothermia was blocked by [D-Phe6, Des-Met14]-bombesin (6-14), ethyl amide, a bombesin/gastrin-releasing peptide receptor antagonist. These data suggest that bombesin/gastrin-releasing peptide receptors are functional in the central nervous system of larval and adult amphibians and that receptor binding can modulate thermoregulation. They raise the question: under what natural conditions is endogenous bombesin/gastrin-releasing peptide released in the brain to activate thermoregulatory behavior?
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PMID:Effects of bombesin on behavioral thermoregulation in the bullfrog. 936 6


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