m-CPP-induced behavioral and neurochemical alterations following longterm intake of rice bran oil in rats

Abstract

Rice bran oil (RBO), a second product of rice bran consists of some extraordinary composition of biologically active and naturally produced antioxidant compounds. meta-Chlorophenylpiperazine (mCPP),  a psychoactive drug of the phenylpiperazine class produces depressive and anxiogenic effects in humans and rodents. It is a postsynaptic 5-hydroxytryptamine (5-HT; serotonin) receptor agonist at 5-HT ₁, 5-HT_1A, 5-HT₂ and 5-HT_2C and antagonistic at 5-HT₃. The present study relates the hypophagic and neurochemical effects of m-CPP following prolong intake of RBO in rats. Male Albino Wistar rats were initially divided into Control and RBO treated groups. Control animals were given only standard rodent diet.  RBO treated rats were given 0.2 ml RBO/day in addition to normal standard rodent food for 6 weeks. Animals of the two groups were again divided into 2 subgroups. Group one was injected with saline in a volume of 1ml/kg body weight. 2nd group was injected with m-cpp at a dose of 3 mg/kg. Food intakes were monitored 4h after the drug administration. Then animals were decapitated. Results showed that m-CPP produced hypophagia in control and also in RBO treated rats, but these effects were greater in RBO treated rats suggesting that the responsiveness of post synaptic hypophagic 5-HT_2C receptors is stimulated by RBO treatment. In addition, m-CPP -induced 5-HT and tryptophan (TRP) levels were reduced in RBO treated than control rats. Plasma corticosterone and glucose levels following m-cpp were also found to be smaller in long term RBO treated animals. The results support the hypothesis that RBO can attenuate stress effects by changing the receptor responsiveness.