Opiate agonist-induced changes in behavioral sensitivity to clonidine are observed in perinatally malnourished rats exposed to chronic stress.
Sensitivity of alpha2-adrenoceptors following repeated immobilization sessions plus morphine (MOR) or beta-endorphin (BETA) was assayed by examining clonidine (CLO)-induced hypoactivity in adult malnourished rats at perinatal age. As previously described, chronic restraint did not attenuate the hypoactivity elicited by CLO in malnourished rats, although chronic restraint did have such an effect on motor activity in control animals. MOR and BETA administration prior to each restraint session induced subsensitivity of alpha2-adrenoceptors in malnourished rats as determined by a blunted response to clonidine challenge. An injection of naloxone (NAL) prior to BETA before each stress session fully antagonized the subsensitivity to clonidine observed in malnourished animals. A possible deficiency in the functional role of the opiate system in the process of adaptation to chronic stress in perinatal malnourished rats is suggested.
Keller
E A
EA
Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
Rey
A
A
Gutiérrez
A C
AC
Cancela
L M
LM
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D003000:Clonidine / Q000494:pharmacology*; D005260:Female; D007103:Immobilization; D009020:Morphine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009748:Nutrition Disorders / Q000503:physiopathology* / Q000523:psychology*; D018847:Opioid Peptides / Q000819:agonists*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000503:physiopathology / Q000523:psychology; D001615:beta-Endorphin / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D009292:Narcotic Antagonists; D018847:Opioid Peptides; D009270:Naloxone; D001615:beta-Endorphin; D009020:Morphine; D003000:Clonidine