RECOVERY OF [H-3] ACETYLCHOLINE SYNTHESIS AFTER AF64A-TREATMENT IN PRIMARY, NEURON-ENRICHED, RAT SEPTAL-HIPPOCAMPAL AND STRIATAL CULTURES

Neuron-enriched cultures prepared from several different rat brain reg ions were incubated with 10 muM or 30 muM monoethylcholine mustard azi ridinium ion (AF64A) under conditions (1 h, 37-degrees-C in Krebs Ring er buffer) that reduced acetycholine (ACh) synthesis coupled to high-a ffinity choline uptake, without affecting choline acetyltransferase ac tivity. Co-cultures of septum-hippocampus and cultures of striatum wer e similarly sensitive to the AF64A-induced inhibition of ACh synthesis . However, ACh-synthesis recovered more rapidly in the striatal-cultur es than in septal-hippocampal co-cultures after AF64A washout. In sept al-hippocampal co-cultures, neither tunicamycin (20 mug/ml) nor cycloh eximide (0.5 mug/ml) had any effect on the basal synthesis of ACh or i ts recovery within 24 h following 10 muM AF64A washout. However, the r ecovery of ACh synthesis in these co-cultures after 30 muM AF64A-washo ut was blocked by either tunicamycin or cyclohexamide. Neither tunicam ycin nor cyclohexamide interfered with ACh-synthesis recovery after wa shout of 30 muM AF64A in striatal cultures. These studies suggest that the turnover of high-affinity choline transporters can be modulated i n a brain-region specific manner in intact primary neuronal cultures.