Ontogenetic determinants of behavioral responses to morphine in rats

Male Sprague-Dawley rats ranging in age from 20 to 110 days were injected with two doses of morphine sulphate, and examined for behavioral activation and catalepsy. Behavioral activation increased with age, while sensitivity to catalepsy declined. Ontogenetic and pharmacological responses suggest possible separate mediation of activation and catalepsy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23324/1/0000264.pd