Rapid decay of cocaine-induced behavioral sensitization of locomotor behavior.
Sprague Dawley rats received three daily intraperitoneal (i.p.) injections of saline or 15 mg/kg cocaine. Following an interval of 2, 5 or 8 days, the behavioral response of separate groups of rats to a challenge injection of cocaine (15 mg/kg) was tested in an open field. After repeated cocaine (15 mg/kg) injection, movement in both the vertical and horizontal plane was increased in cocaine-treated rats 2, but not 5 or 8, days after treatment as compared to saline-treated subjects. In addition, behavioral ratings along an ordinal scale designed to reflect increases in behavioral activation were increased in cocaine-treated rats 2, but not 5 or 8, days after treatment. These results stand in contrast to other reports demonstrating long-lasting neural and behavioral changes after similar treatment regimens. Taken together, the results suggest that a treatment regimen of 15 mg/kg per day of cocaine for 3 days produces behavioral sensitization of locomotor behavior; however, this cocaine-induced behavioral sensitization does not persist beyond a few (< 5) days after repeated cocaine treatment, using the current experimental parameters.
Janak
P H
PH
Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Winston-Salem, NC 27157, USA. janak@biogfx.bgsm.wfu.edu
Hernandez
R V
RV
Rule
R R
RR
Martinez
J L
JL
D000818:Animals; D003042:Cocaine / Q000633:toxicity*; D008297:Male; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013239:Stereotyped Behavior / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D003042:Cocaine