Effect of clonidine on the responsiveness of infant rats to maternal stimuli.
Clonidine (0.1 mg/kg), an alpha 2-adrenoceptor agonist, stimulated ultrasonic callings in 10-day-old rats. Unlike normal isolated rat pups, the vocalizations of clonidine-treated rats appeared resilient to maternal cues. Thus, clonidine-induced vocalizations did not decrease during intraoral infusions with 10% sucrose, exposure to home cage bedding or tactile stimulation of the skin. Clonidine (0.05; 0.1; 0.2 mg/kg) also disrupted the attraction normally shown by infant rats to home cage odours in an olfactory place preference test. This effect by clonidine was not shared by raclopride (1-4 mg/kg), naltrexone (0.5-2.0 mg/kg) or propranolol (2.5-10.0 mg/kg). Clonidine-treated infants (0.05; 0.1; 0.2 mg/kg) also failed to apprehend and attach to the anaesthetized mother's nipple. The results raise the possibility that alpha 2-adrenoceptor activation blunts the infant's receptivity to maternal olfactory incentives and intensifies separation-induced responses.
Hansen
S
S
Department of Psychology, University of Göteborg, Sweden.
D000818:Animals; D000831:Animals, Newborn / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D002755:Choice Behavior / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D008425:Maternal Behavior; D009043:Motor Activity / Q000187:drug effects; D009271:Naltrexone / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D020891:Raclopride; D051381:Rats; D017208:Rats, Wistar; D012457:Salicylamides / Q000494:pharmacology; D012903:Smell / Q000187:drug effects; D013391:Sucking Behavior / Q000187:drug effects; D013395:Sucrose / Q000494:pharmacology; D014828:Vocalization, Animal / Q000187:drug effects
D018492:Dopamine Antagonists; D012457:Salicylamides; D020891:Raclopride; D013395:Sucrose; D009271:Naltrexone; D011433:Propranolol; D003000:Clonidine