Effects of 3-benzidino-6-phenylpyridazine, as an acetylcholinesterase inhibitor, on outward potassium current in acutely isolated rat hippocampal pyramidal neurons

As an acetylcholinesterase (AChE) inhibitor, the effects of 3-benzidino-6-phenylpyridazine (BPP) on outward potassium current including delayed rectifier potassium current (IK(DR)) and transient outward potassium current (IK(A)) in acutely isolated rat hippocampal pyramidal neurons were studied, using the whole cell patch-clamp technique. BPP reversibly inhibited electric eel AChE as an inhibitor, with IC50 of 1.43 μM. BPP (0.10-100 μM) decreased IK(DR) and IK(A) in a concentration-dependent, voltage-independent and partial reversible manner, with IC50 of 0.47 and 0.31 μM, respectively. 10 μM BPP did not affect steady-state activation of IK(DR) and IK(A). In addition, 10 μM BPP shifted the voltage dependence of steady-state inactivation of IK(A) towards negative potential. In conclusion, BPP potently inhibits IK(DR) and IK(A) in rat hippocampal pyramidal neurons, which may contribute to BPP's restoring the damaged central nervous system.