TY - JOUR
T1 - The effects of clonidine on the partial reinforcement extinction effect (PREE)
AU - Halevy, G.
AU - Feldon, J.
AU - Weiner, I.
PY - 1986/8
Y1 - 1986/8
N2 - Clonidine has been reported to exert anti-anxiety effects in animals and man similar to those of benzodiazepines. The present experiment examined the effects of clonidine administration on the partial reinforcement extinction effect (PREE) which is known to be sensitive to benzodiazepine action. Two groups of rats were trained to run in a straight alley. The continuously reinforced (CRF) group received food reward on every trial. The partially reinforced (PRF) group was rewarded on a quasi-random 50% schedule. All animals were then tested in extinction. Clonidine 50 μg/kg was administered in a 2×2 design, i.e., drug-no drug in acquisition and drug-no drug in extinction. The PREE, i.e., increased resistance to extinction exhibited by PRF animals as compared to CRF animals, was obtained in animals that received saline in acquisition, independently of drug treatment in extinction, as well as in animals that received clonidine in both acquisition and extinction, but not in animals that received clonidine in acquisition alone. The administration of clonidine in extinction alone increased resistance to extinction in both the CRF and PRF animals. The increase in resistance to extinction, typically obtained with benzodiazepine treatment, indicates that clonidine exerts anxiolytic effects, supporting the involvement of the noradrenergic system in anxiety. However, clonidine did not fully reproduce the effects of benzodiazepines on the PREE, suggesting that the two classes of drugs may act via different noradrenergic mechanisms.
AB - Clonidine has been reported to exert anti-anxiety effects in animals and man similar to those of benzodiazepines. The present experiment examined the effects of clonidine administration on the partial reinforcement extinction effect (PREE) which is known to be sensitive to benzodiazepine action. Two groups of rats were trained to run in a straight alley. The continuously reinforced (CRF) group received food reward on every trial. The partially reinforced (PRF) group was rewarded on a quasi-random 50% schedule. All animals were then tested in extinction. Clonidine 50 μg/kg was administered in a 2×2 design, i.e., drug-no drug in acquisition and drug-no drug in extinction. The PREE, i.e., increased resistance to extinction exhibited by PRF animals as compared to CRF animals, was obtained in animals that received saline in acquisition, independently of drug treatment in extinction, as well as in animals that received clonidine in both acquisition and extinction, but not in animals that received clonidine in acquisition alone. The administration of clonidine in extinction alone increased resistance to extinction in both the CRF and PRF animals. The increase in resistance to extinction, typically obtained with benzodiazepine treatment, indicates that clonidine exerts anxiolytic effects, supporting the involvement of the noradrenergic system in anxiety. However, clonidine did not fully reproduce the effects of benzodiazepines on the PREE, suggesting that the two classes of drugs may act via different noradrenergic mechanisms.
KW - Clonidine
KW - Continuous reinforcement
KW - Partial reinforcement
KW - Rat
KW - Resistance to extinction
UR - http://www.scopus.com/inward/record.url?scp=0022534070&partnerID=8YFLogxK
U2 - 10.1007/BF00172878
DO - 10.1007/BF00172878
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AN - SCOPUS:0022534070
SN - 0033-3158
VL - 90
SP - 95
EP - 100
JO - Psychopharmacology
JF - Psychopharmacology
IS - 1
ER -