HIV gp120 and morphine alter mu opiate receptor expression in human vascular endothelium

We find that chronic exposure of human saphenous vein, atria and internal t horacic artery endothelium to the human immunodeficiency virus surface glyc oprotein gp120, results in an increase in endothelial mu opioid receptor ex pression (52%). gp120 acts, in this regard, as a proinflammatory cytokine ( e.g. interleukin-1-alpha) by increasing endothelial mu opioid receptor expr ession. In contrast, morphine decreases mu opioid receptor expression by 90 % in a dose dependent fashion. Pretreatment of these tissues with the respe ctive antagonists e.g., naloxone and anti-gp120 blocks the opiate decrease and increase gp120 induced increase in CL expression, respectively. Further , pretreatment of these endothelia with morphine inhibits gp120-stimulated mu transcript expression. Therefore, the immune down-regulating action of m orphine may prevent viral replication because this process requires immune activation that can, in part, be provided for by gp120 proinflammarory acti ons.