Effects of chronic cocaine administration on aggressive behavior in virgin rats.
Virgin Sprague-Dawley rats received subcutaneous injections of saline, 3.5, 7.5 or 15 mg/kg of cocaine, twice daily, for 20 consecutive days. Females were videotaped for 10 minutes in the presence of a male rat for assessment of aggression towards the intruder 2, 3, and 5 days following cessation of cocaine or saline administration. Oxytocin levels in discrete brain areas were assayed following behavioral testing, 5 days following cessation of cocaine or saline administration. The 30 mg/kg-dose group tended to have a lower frequency of fight attacks and aggressive postures compared to saline-treated controls across sessions. The frequency of most of the behaviors analyzed were represented by quadratic functions across time, such that the highest frequency of behavior occurred 2 days following the final injection with relatively less activity 3 and 5 days following cessation of saline or cocaine administration. The 30 mg/kg cocaine-treated group had significantly lower hippocampal OT levels than the 15 mg/kg group 5 days following cessation of cocaine or saline administration.
Lubin
D A
DA
Department of Psychology, University of North Carolina at Chapel Hill, 27599, USA. dlubin@css.unc.edu
Meter
K E
KE
Walker
C H
CH
Johns
J M
JM
D000374:Aggression / Q000187:drug effects* / Q000502:physiology; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D007279:Injections, Subcutaneous; D008297:Male; D010121:Oxytocin / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D018765:Dopamine Uptake Inhibitors; D010121:Oxytocin; D003042:Cocaine