Interaction of colchicine with nitric oxide in CA1 on the expression of drug- seeking behavior induced by morphine

Introduction: According to previous studies, colchicine causes neuronal destruction and learning depression. In this project, effects of colchicine injection into the CA1 and interaction between colchicine and nitric oxide (NO) in this area on the expression of drug-seeking behavior were investigated. Methods: Wistar rats (250-300 g) were bilaterally cannulated at the CA1 area. Colchicine (2-8 μg/rat) was bilaterally administered after the placement of the cannulas and the treated animals were then allowed to recover for about 1 week before behavioral measurements began. Place conditioning was induced by morphine (2.5-5 mg/kg/day, s.c.) and conducted using a five-day schedule of an unbiased task including familiarization, conditioning and testing. NO agents were injected into the CA1 on the day of the testing and the data were analyzed by ANOVA after reviewing the data recorded by Ethovision. Results: Colchicine significantly reduced the drug-seeking behaviors but morphine caused an increase in these behaviors of colchicine treated rats. NO agents did not show any significant effect except for the compartment entering. Conclusion: Colchicine may decrease the CA1 neural cell population but morphine increases the signs through a mechanism, which is probably dopamine dependent. The NO agents may produce the effects by dopamine due to induction of morphine.