Effect of chronic neonatal morphine and naloxone on sensorimotor and social development of young rats.
Chronic morphine treatment of newborn Long-Evans rat pups between 3-26 days of age (thrice daily starting with 0.5 mg/kg, increased daily by 0.5 mg/kg to 10 mg/kg) led to lags of 1 to 3 days in physical development (body weights and eye opening times) and motor coordination (catalepsy test, grasping, swimming). Chronic naloxone treatment (5 mg/kg administered thrice daily from day 3-26), in contrast, led to modest gains in development on a number of measures (body weights, vaginal opening). Morphine animals also lagged behind controls and naloxone-tested animals in social behaviors, such as homing and play. Chronic naloxone did not block or retard social development; in fact naloxone-treated animals exhibited more rapid acquisition of homing behavior than controls.
Najam
N
N
Department of Psychology, Bowling Green State University, OH 43403.
Panksepp
J
J
D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D001522:Behavior, Animal / Q000187:drug effects*; D004334:Drug Administration Schedule; D005260:Female; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects*; D051381:Rats; D012919:Social Behavior
D009270:Naloxone; D009020:Morphine