Background and purposes: Arachidonic acid cascade has been indicated to be involved in the mechanisms underlying drug dependence and relapse. Virgin Coconut Oil (VCO) has been demonstrated to have anti-inflammatory activity assumed to be related to the cascade. The research was aimed to investigate the effect of VCO in rat model of nicotine dependence and relapse at behavioral level using conditioned place preference (CPP) method, and to assess the consequences on the expression of prostaglandin EP3 receptor (EP3R) protein in the brain. Method: The rats were assigned to one of the following treatment groups: place conditioning without drug treatment before nicotine injection (0.5 mg/kg, i.p), training with pretreatment VCO (5 ml/kg, p.o), or diclofenac (3.2 mg/kg, i.p) 30 minutes prior to each nicotine treatment. The conditioning training lasted for 5 days, followed by a conditioning test on the following day. In different batch of rats, conditioning test was followed by a 7-day period without nicotine, and rats were then challenged with nicotine on the following day. VCO and diclofenac were given 30 minutes before nicotine challenge to test their effects. For examination of the expression of EP3R protein, the olfactory bulb, cerebellum and hippocampus of the brain were isolated and immunohistochemistry procedure was carried out to these brain areas. Result: Repeated nicotine exposure led to nicotine dependence, indicated by the increase in preference score (p <0.05) in the preference test. VCO (5 ml/ kg, p.o) and diclofenac (3.2 mg/ kg, i.p) decreased the preference scores in the evaluation of nicotine dependence and relapse (p <0.01). Expression of EP3R protein in all parts of the brain tested appeared to be increased in test animals given only nicotine, and VCO and diclofenac decreased the expression of the protein. Conclusion: Results of the present study suggested that VCO reduces nicotine dependence and relapse, which might be associated with decreased expression of EP3R protein.
Yangie Dwi Marga Pinanga
for God, families, country, society, and world.