Acetylcholine receptors in dissociated nucleus basalis of Meynert neurons of the rat

Electrical and pharmacological properties of acetylcholine (ACh)-induced currents in neurons dissociated from the nucleus basalis of Meynert (nBM) of immature (2-week-old) rats were investigated with the whole-cell mode of the patch-clamp technique. At a holding potential (V_H) of ?50 mV, ACh (10^?4M) evoked a transient inward current mimicked by nicotine (I_nACh), followed by a sustained outward current mimicked by carbamylcholine (I_mACh). The K_D values were 1.2 × 10^?4 M for I_nACh) and 8.7 × 10^?7 M for I_mACh. The reversal potenial of I_mACh was close to E_K. The I_mACh was determined to be elicited via the M₂ muscarinic receptor, based on the differences in sensitivity to muscarinic antagonists such as pirenzepine and AF-DX-116.