Role of K+ channels in regulating spontaneous activity in the muscularis mucosae of guinea pig bladder.

摘要: To explore the roles of various K+ channels in regulating spontaneous activity bladder muscularis mucosae (MM) that is considered to play an important role maintaining mucosal function. Effects channel modulators on electrical and contractile guinea-pig MM were examined using intracellular microelectrode isometric tension recording. The predominately generated bursting action potentials (SAPs) phasic contractions (SPCs) blocked by nifedipine (1µM). NS309 (10µM), a small-conductance Ca2+-activated (SK) opener, dramatically prolonged after-hyperpolarisation (AHP) converted SAPs into individually apamin (100nM)-sensitive manner. Apamin alone increased number during bursts. NS1619 large-conductance (BK) abolished manner reversed iberiotoxin (IbTX, 100nM), BK blocker. IbTX enlarged their AHPs. Flupirtine voltage-dependent (Kv7) diminished XE991 Kv7 exerted modest excitatory effects SAPs. These had corresponding SPCs. Bursting SAP firing appears result from lower level activation SK than DSM. predominant configuration, while have only marginal role. prevention associated reduction SPCs upon pharmacological reserved population may well considerable therapeutic potential.