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Altered thermoregulatory responses to clonidine in streptozotocin‐diabetic rats
Author(s) -
O'Donnell J.M.,
Banyasz T.,
Kovacs T.
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15284.x
Subject(s) - idazoxan , clonidine , yohimbine , endocrinology , medicine , (+) naloxone , streptozotocin , antagonist , thermoregulation , imidazoline receptor , chemistry , prazosin , diabetes mellitus , receptor
1 The effects of streptozotocin (STZ) treatment on α 2 ‐adrenoceptor regulation of body temperature were studied by monitoring the response of colonic temperature to administration of clonidine. 2 A dose‐dependent fall in colonic temperature occurred in control rats given clonidine challenge (0.05‐2.0 mg kg −1 , s.c.); this response was inhibited by prior administration of either yohimbine or idazoxan (2 mg kg −1 , s.c.) but not by the peripherally‐acting α 2 ‐adrenoceptor antagonist L‐659,066 (10 mg kg −1 , s.c.). 3 In rats treated with STZ (65 mg kg −1 , i.v.) administration of clonidine elicited a dose‐independent hyperthermia (circa 1°C.); this effect was unaltered by prior administration of yohimbine or idazoxan. 4 Naloxone (5 mg kg −1 , s.c.) elicited a small fall in temperature(< 1°C.) in both control and STZ‐treated rats; naloxone pretreatment did not alter the temperature response to clonidine in either group. 5 Nicotinic acid (10 mg kg −1 , s.c.) caused a similar small elevation in temperature in both groups. 6 Administration of replacement insulin to STZ‐treated rats maintained weight gain and low blood glucose while the thermoregulatory response to clonidine slowly reverted to normal. 7 These results show that altered central temperature control is an element of the generalised abnormality of α 2 receptor function induced by STZ.