EFFECT OF NICOTINE ADMINISTRATION ON THE EXPRESSION OF ENKEPHALIN AND DELTA-OPIOID RECEPTOR (DOR) mRNA OF THE RAT BRAIN
Project no. 1076 · Status: Kapanmış · 2016
Summary
Kappa opioid receptors (KOR) and their endogenous ligands, prodynorphin (PDYN) -derived opioid peptides are proposed as important mediators of nicotine reward. This study investigated the regulatory effect of chronic nicotine treatment on the gene expression of KOR and PDYN in the mesocorticolimbic system. Three groups of rats were injected subcutaneously with nicotine at doses of 0.2, 0.4, or 0.6 mg/kg/day for 6 days. Rats were decapitated 1 hr after the last dose on day six, as this timing coincides with increased dopamine release in the mesocorticolimbic system. mRNA levels in the ventral tegmental area (VTA), lateral hypothalamic area (LHA), amygdala (AMG), dorsal striatum (DST), nucleus accumbens (NAc), and medial prefrontal cortex (mPFC) were measured by quantitative real-time PCR. Our results showed that PDYN mRNA was reduced in the LHA with 0.6 mg/kg nicotine and in the AMG with 0.4 mg/kg nicotine. KOR mRNA was also decreased in the DST with 0.6 mg/kg nicotine.