Effect of morphine on the cAMP level of lymphocytes

A study was made of the effect of morphine on the cAMP level in peripheral blood lymphocytes in tobacco smoking and non-smoking donors. Morphine was shown to produce the naloxone-removable activation of adenylate cyclase, the relationship between enzymatic activity and opiate concentration in the medium being complex in nature. In tobacco smoking donors, the maximal effect on cAMP was produced by morphine at concentrations that were one order of magnitude higher than those in non-smoking ones. On the basis of the data obtained the assumptions are made (1) about the presence on the lymphocytes of opiate receptors whose action mode is associated with adenylate cyclase control, and (2) about the development during tobacco smoking of morphine tolerance at the level of opiate-dependent adenylate cyclase of lymphocytes.