ISSN:
1432-2072
Keywords:
Propranolol
;
Beta-adrenergic blocker
;
Differential reinforcement of low rates of response (DRL)
;
Anxiety
;
Antianxiety drugs
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Rats were trained over 40 days to lever-press for food reward under a schedule of differential reinforcement of low rates of response with a 20-s criterion (DRL 20), following seven sessions of continuous reinforcement. The effect of injecting a beta-adrenergic blocker, propranolol (5 mg/kg IP), before and at two different delays after each daily session of DRL were investigated. In Experiment I, rats drugged 5–8 min before every session earned fewer reinforcements compared to controls, and showed impaired temporal discrimination. In Experiment II, this result was not replicated, but similar effects were clear in animals drugged pre-session from the 15th day of acquisition. By contrast, an improved temporal discrimination, and increased number of reinforcements were seen in rats drugged 5–8 min after every session. In Experiment III, the postsession effects were replicated and found also in rats drugged 4–5.5 h after each session. These results suggest that propranolol has an acute effect on DRL responding which resembles that of anxiolytics, and a chronic effect which opposes the acute one.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00427913
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