No abstract

CREATINE synthesis was first demonstrated by BORSOOK and DUBNOFF (1940) in experiments in which rat liver slices were incubated with guanidoacetic acid and methionine. In subsequent studies, DUVIGNEAUD (1941, 1956) demonstrated that the methyl group of methionine is transferred as a unit to guanidoacetic acid to form creatine in tlico. BLOCK and SHOENHEIMER (194l), using [15N]-labelled compounds, and BORSOOK and DUBNOFF (1941) using kidney slices and cell free extracts, later demonstrated guanidoacetic acid synthesis from arginine and glycine. BORSOOK and DUBNOFF (1941) proposed a mechanism, accommodating all of these findings, whereby

The authors review the evidence that cocaine exerts its rewarding effects through the acute activation of dopamine (DA) pathways in the brain. Chronic cocaine administration is hypothesized to lead to DA depletion, which results in cocaine craving and cocaine abstinence states. Treatment of these states with bromocriptine, a DA/antagonist, appears to have efficacy with acute and maintenance trials, and may represent a new adjunctive treatment for cocaine abuse. DA antagonists appear to exacerbate cocaine craving, which is consistent with the DA depletion hypothesis of chronic cocaine abuse. Theoretical issues relating to drug addiction and endogenous reward centers are discussed.

No abstract