The effect of short-chain fatty acids on Cl− and K+ conductance in rat colonic crypts

摘要: The effect of butyrate on membrane potential and currents colonic enterocytes was studied with the whole-cell patch-clamp method. Superfusion crypts from rat distal colon butyrate-containing solutions induced a depolarization 16.5±2.3 mV. This response only observed in upper third crypt. dependent presence Cl− accompanied by an increase inward current, indicating that it is caused conductance. Membrane outward however, behaved inconsistently. Whereas most cells observed, about 25% responded decrease. unexpected inhibition current probably represents decrease K+ conductance cellular acidification butyrate. Ma-noeuvres carried out to acidify cell interior, like perfusion acid buffer or Na+/H+ exchanger amiloride, mimicked this Orientating cell-attached recordings performed parallel revealed activation previously silent basolateral channels They had linear current/voltage relationship single-channel 20–30 pS. butyrate-induced not intracellular adenosine 5′-triphosphate (ATP) also when capacity pipette for Ca2+ increased. It inhibited guanosine-5′-O(2-thiodiphosphate) (GDP[βS]). In lipoxygenase inhibitor, nordihydroguaiaretic (NDGA), even reversed slight hyperpolarization channels, but are stimulated leukotriene. could be administration leukotriene D4 (LTD41, 5×10−7 mol · l−1). eicosanoid depolarization, which completely Cl−. Consequently, LTD4 likely candidate metabolite, activates channels. seems mediated protein phosphorylation G-protein.