BIFURCATION MODEL OF DRUG-DEPENDENCE

Chronic administration of narcotics produces alterations which persist for a long time following cessation of drug usage in a state of absti nence. The current model of drug dependence which is based on the narc otic-induced alterations of adenylatecyclase synthesis and activity ca nnot explain these long-term changes. The possible modification of thi s model suitable to explain the slate of abstinence; is described. The modified model consists of two non-linear differential equations desc ribing the dynamics of enzyme synthesis and enzyme-product interaction . Under certain conditions narcotics interconvert the regulatory syste m from 'normal' equilibrium to an 'abstinent' slate in which the syste m can remain indefinitely, even in tile absence of narcotics. Copyrigh t (C) 1997 Elsevier Science IreIand Ltd.