Date of Award

1994

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

First Advisor

Paula J. Geiselman

Abstract

Bombesin is a tetradecapeptide first isolated from frog skin. This peptide has potent effects on core body temperature of rats when administered centrally. Bombesin-induced hypothermia at normal ambient temperatures appears to be dependent upon some pre-existent condition which may be related to nutritional status. Four experiments were conducted to examine if the pre-existing condition for bombesin-induced hypothermia at normal ambient temperatures is primarily related to modulation of sympathetic nervous system activation. Experiment I demonstrated that central bombesin resulted in hypothermia in rats tested at normal ambient temperatures under conditions of ad-libitum access to food only when injected peripherally with the ganglionic blocker chlorisondamine. Experiment II demonstrated that bombesin-induced hypothermia in ad-libitum fed rats treated with chlorisondamine is prevented by peripheral injection with the $\beta\sb3$-adrenergic receptor agonist, CL-316,243. Experiment III demonstrates that bombesin-induced hypothermia seen in acutely food-deprived rats is prevented by peripheral injection of CL-316,243. Experiment IV establishes that bombesin-induced hypothermia seen in acutely food-deprived rats is not dependent upon adrenal catecholamines and that peripheral corticosterone injection may promote hypothermia, possibly by suppression of corticotrophin-releasing hormone. The results are discussed in relation to sympathetic nervous system modulation and nutritional status.

Pages

111

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