INDICATION OF METHAMPHETAMINE-INDUCED REACTIVE SYNAPTOGENESIS IN THE PREFRONTAL CORTEX OF GERBILS (MERIONES-UNGUICULATUS)

A single dose of methamphetamine (25 mg/kg i.p.) was administered to y oung adult gerbils (Meriones unguiculatus) aged 90 days and the number of spices was determined along 40-mum segments of basal, lateral and apical dendrites of pyramidal cells in layers III and V of the prefron tal cortex, after 1.5, 7, 20 and 30 days. The density of spines rapidl y increased by more than 80% within 7 days after drug challenge, and s ubsequently returned to the original normal values within about 2 week s. Thirty days after drug administration the density of dendritic spin es was slightly, but significantly, less than control values (about 5% ). The density of spines was likewise affected in layer III and V neur ones, irrespective of the spatial domain of their dendritic ramificati ons. Since several lines of investigation indicate that methamphetamin e can cause the destruction of dopaminergic nerve terminals in the mam malian forebrain, the present results are discussed against the backgr ound of current concepts about reactive synaptic reorganization and ad aptive remodelling of neural circuits in the central nervous system.