Progesterone does not affect cocaine-induced conditioned place preference or locomotor activity in male rats.
BACKGROUND
The present study aimed to determine if, as occurs in female rats, progesterone attenuates cocaine-induced reward and psychomotor responses in male rats.


METHODS
The role of progesterone in the acquisition and/or expression of cocaine-induced conditioned place preference (CPP) and locomotor responses of intact male rats was studied. For chronic progesterone treatment, rats received Silastic capsules with either progesterone (100%) or vehicle 1 week prior to conditioning. For acute progesterone treatment, rats received subcutaneous injections of progesterone (500 microg) or vehicle (sesame oil) 4 hours before intraperitoneal injections of saline or cocaine administration (20 mg/kg) on conditioning days (acquisition phase-formation of reward associations) or before testing (expression phase-recall of reward associations).


RESULTS
Both progesterone-treatment paradigms produced equivalent progesterone serum levels. Progesterone administered chronically or acutely during the acquisition and expression phases of cocaine conditioning did not block cocaine-induced CPP. Nor did progesterone affect ambulatory or rearing behaviors after cocaine administration.


CONCLUSIONS
These results suggest that, unlike the findings with female rats (in which similar treatment paradigms inhibited the formation and recall of cocaine-induced CPP), progesterone plays a limited role in the cocaine-induced reward or psychomotor responses of male rats.
Department of Psychology, Hunter College, New York, NY 10065, USA.
Scott J
SJ
Russo
Wei Lun
WL
Sun
Ana Christina E
AC
Minerley
Karen
K
Weierstall
Arbi
A
Nazarian
Eugene D
ED
Festa
Tipyamol
T
Niyomchai
Alaleh
A
Akhavan
Shirzad
S
Jenab
Vanya
V
Quiñones-Jenab
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003042:Cocaine / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000503:physiopathology; D003213:Conditioning, Psychological / Q000187:drug effects*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D011372:Progestins / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D021641:Recognition, Psychology / Q000187:drug effects
D018765:Dopamine Uptake Inhibitors; D011372:Progestins; D011374:Progesterone; D003042:Cocaine