Down-regulation of opoid receptor gene expressions in T-lymphocytes of heroin users

Abstract

Our previous study indicated a suppression of mitogen-stimulated T-lymphocyte proliferation, both as an in vitro effect of morphine and in heroin addicts. This immunosuppression is possibly mediated via a direct interaction of opioid with opioid receptors on T-cells. Opioid receptor gene expressions on the immune cells of heroin abusers were determined by using a semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR) technique with specific pairs of primers to amplify mu- and delta-opioid receptor mRNAs. Both types of mRNAs were significantly decreased in T-cells of heroin abusers. The levels were normal in those heroin-withdrawal subjects. The present data indicates that gene expressions of opioid receptors were down-regulated in lymphocytes of heroin abusers. This is the first evidence showing an alteration of lymphocyte opioid receptor gene expression in heroin users. Further elucidation of the mechanisms involved in this regulation may lead to a better understanding of cellular and molecular opioid-induced immunomodulation.