TY - JOUR
T1 - Effects of amphetamine, butorphanol, and morphine pretreatment on the maintenance and reinstatement of cocaine-reinforced responding
AU - Lynch, Wendy J.
AU - Heaser, Wayne A.
AU - Carroll, Marilyn E
PY - 1998/8
Y1 - 1998/8
N2 - Three groups of rats (N = 23) self-administered intravenous cocaine (0.4 mg/kg/infusion) during the initial 2 hr of daily 7-hr sessions. During the remaining 5 hr of these sessions, responding produced saline infusions. On test days, each rat was pretreated with an assigned dose of either butorphanol, morphine, amphetamine, or saline before the self-administration session followed by a printing injection of cocaine (3.2 mg/kg iv) or saline at the beginning of the 4th hr. Results showed that both amphetamine (0.5, 1.0, and 2.0 mg/kg) and morphine (0.3, 1.0, and 2.0 mg/kg) pretreatment dose-dependently reduced cocaine self-administration whereas only amphetamine affected (increased) reinstatement responding. Butorphanol pretreatment (8 mg/kg) suppressed cocaine self-administration and blocked the effect of the cocaine priming injections on pretreatment testing days. These findings indicate that (a) pretreatment drugs with similar stimulus properties potentiate reinstatement of responding and (b) pretreatment drugs can differentially affect maintenance and reinstatement of responding.
AB - Three groups of rats (N = 23) self-administered intravenous cocaine (0.4 mg/kg/infusion) during the initial 2 hr of daily 7-hr sessions. During the remaining 5 hr of these sessions, responding produced saline infusions. On test days, each rat was pretreated with an assigned dose of either butorphanol, morphine, amphetamine, or saline before the self-administration session followed by a printing injection of cocaine (3.2 mg/kg iv) or saline at the beginning of the 4th hr. Results showed that both amphetamine (0.5, 1.0, and 2.0 mg/kg) and morphine (0.3, 1.0, and 2.0 mg/kg) pretreatment dose-dependently reduced cocaine self-administration whereas only amphetamine affected (increased) reinstatement responding. Butorphanol pretreatment (8 mg/kg) suppressed cocaine self-administration and blocked the effect of the cocaine priming injections on pretreatment testing days. These findings indicate that (a) pretreatment drugs with similar stimulus properties potentiate reinstatement of responding and (b) pretreatment drugs can differentially affect maintenance and reinstatement of responding.
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U2 - 10.1037/1064-1297.6.3.255
DO - 10.1037/1064-1297.6.3.255
M3 - Article
C2 - 9725109
AN - SCOPUS:0031826632
VL - 6
SP - 255
EP - 263
JO - Experimental and Clinical Psychopharmacology
JF - Experimental and Clinical Psychopharmacology
SN - 1064-1297
IS - 3
ER -