Acute and chronic effects of propranolol on extinction of rewarded running in the rat.
Three experiments examined the effect of propranolol injected IP on a series of 16 extinction trials at 24-hour intertrial intervals after continuously rewarded running. In Experiment I, propranolol (1, 5 or 10 mg/kg) was injected, in different groups, shortly before or shortly after each extinction trial, but without effect. In Experiment II, the same doses were injected daily for 18 days preceding extinction, to allow longer for any long-term drug effect to accumulate. Propranolol (1 mg/kg) facilitated extinction. In Experiment III, a single dose (7.5 mg/kg) was injected before or after extinction trials as in Experiment I; the acute effect was to impair extinction. These results are consistent with previous findings in the Skinner box that propranolol has an acute disinhibitory effect on nonrewarded responses and a long-term inhibitory one. These effects have different dose-response relationships.
Terry
P
P
Department of Psychology, University College London, UK.
Wray
N
N
Salmon
P
P
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005108:Extinction, Psychological / Q000187:drug effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012201:Reward; D013997:Time Factors
D011433:Propranolol