Effects of phentolamine and clonidine on pituitary-adrenocortical axis during stress in conscious rats.
For evaluation of the effect of several drugs on the hypothalamo-pituitary-adrenocortical axis during stress, after testing various tress stimuli (swimming, restrain) the 15 min exposure of rats to novel environment was chosen. Subcutaneous administration of clonidine hydrochloride (BOEHRINGER; Ingelheim, 60 micorgram kg-1), a drug stimulating alpha-adrenergic receptors, did not result in any any changes in plasma corticosterone level either during basal or under stress conditions. In contrast, the administration of alpha-adrenergic blocking agent--phentolamine (RegitineR CIBA; 4 mg kg-1)--produced a significant elevation of resting corticosterone level, but failed to influence the stress-induced corticosterone increase.
D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D003345:Corticosterone / Q000097:blood; D008297:Male; D010646:Phentolamine / Q000494:pharmacology*; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D051381:Rats; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*
D003000:Clonidine; D003345:Corticosterone; D010646:Phentolamine