Peripheral noradrenaline depletion does not impair extinction of food-rewarded running in the rat.
To test whether the sympathetic nervous system influences the inhibition of non-rewarded running in the runway, we examined the effects of peripheral noradrenaline depletion, induced by 6-hydroxydopamine (6-OHDA HBr, 30 mg/kg, i.p.), on extinction of food-rewarded running in rats. This was done in two separate experiments. In the first, in which the inter-trial interval (ITI) was one day and rats were injected before acquisition, running times at the end of extinction did not differ. The 6-OHDA appeared to slow down running times at the end of acquisition and the start of extinction. In the second experiment (15 s ITI) therefore, rats were injected after stable running had been acquired; there was no effect on running in subsequent rewarded trials. In extinction, although the groups ran similarly at first, the 6-OHDA treated animals subsequently ran more slowly than the controls; that is they showed greater extinction. Taken together with other published evidence, the sympathetic nervous system does not appear to contribute to the extinction of continuously reinforced responses.
D000818:Animals; D005502:Food; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D012201:Reward; D012420:Running
D006892:Hydroxydopamines; D016627:Oxidopamine; D009638:Norepinephrine