MODULATORY ACTION OF CHOLINERGIC DRUGS ON N-METHYL-D-ASPARTATE RESPONSE IN DISSOCIATED RAT NUCLEUS BASALIS OF MEYNERT NEURONS

The effect of cholinergic drugs on N-methyl-D-aspartate (NMDA)-activated responses in neurons dissociated freshly from the nucleus basalis of Meynert (nBM) of immature and mature rats were investigated with the whole-cell patch-clamp technique. The NMDA (10(-4) M) -evoked inward current (I(NMDA)) consisted of transient peak and successive steady-state components. In mature neurons, the peak component was suppressed by pretreatment with acetylcholine (ACh, 10(-12)-10(-5) M) but facilitated by higher concentrations (> 10(-5) M). Regardless of the concentration, ACh had no effect on I(NMDA) of immature neurons. The results suggest that ACh behaves as either inhibitory or excitatory modulator of glutaminergic transmission in nBM neurons of adult mammals depending on ACh concentration.