A role for corticotropin-releasing factor, but not corticosterone, in acute food-deprivation-induced reinstatement of heroin seeking in rats.
BACKGROUND
Acute 1-day food deprivation reinstates heroin seeking in rats via a leptin-dependent mechanism. However, leptin has no effect on footshock- or heroin-priming-induced reinstatement of drug seeking. These data may indicate that the neuronal systems underlying food-deprivation-induced reinstatement are dissociable from those involved in reinstatement induced by footshock stress.


OBJECTIVE
We used the reinstatement procedure to examine the roles of the adrenal stress hormone, corticosterone, and brain corticotropin-releasing factor (CRF) in acute food-deprivation-induced reinstatement of extinguished heroin seeking in rats.


METHODS
The rats were trained to press a lever for heroin (0.05-0.1 mg/kg/infusion, i.v.) for 10 days. Experiment 1: After heroin self-administration training, the rats were divided into two groups, which received either bilateral adrenalectomy surgery or sham surgery. Next, the rats were given 7-10 days of extinction training (during which lever presses were not reinforced with heroin). The rats were subsequently tested for reinstatement after acute (21 h) food deprivation. Experiment 2: After heroin self-administration and extinction training, the rats were tested for reinstatement induced by acute food deprivation. Before the test session, the rats were given intracerebroventricular injections of the CRF receptor antagonist alpha-helical CRF (0, 3, or 10 microg/rat).


RESULTS
Adrenalectomy had no effect on the extinction behavior or acute food-deprivation-induced reinstatement of heroin seeking. The CRF receptor antagonist, alpha-helical CRF, dose-dependently blocked food-deprivation-induced reinstatement.


CONCLUSIONS
The present data suggest that, as demonstrated for footshock-induced reinstatement of drug seeking, brain CRF, but not corticosterone, plays a critical role in acute food-deprivation-induced reinstatement of heroin seeking.
Shalev
Uri
U
Department of Psychology, Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, Quebec, Canada. uri.shalev@concordia.ca
Finnie
Peter S
PS
Quinn
Tammie
T
Tobin
Stephanie
S
Wahi
Priti
P
D000315:Adrenalectomy; D000818:Animals; D003042:Cocaine / Q000008:administration & dosage; D003345:Corticosterone / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D005108:Extinction, Psychological; D005508:Food Deprivation; D003932:Heroin / Q000008:administration & dosage*; D008297:Male; D009714:Nucleus Accumbens / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012646:Self Administration; D017557:Ventral Tegmental Area / Q000502:physiology
D003932:Heroin; D003346:Corticotropin-Releasing Hormone; D003042:Cocaine; D003345:Corticosterone