A basolateral K+conductance modulated by carbachol dominates the membrane potential of small intestinal crypts

✍ Scribed by R. J. Walters; F. V. Sepúlveda

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 325 KB
• Volume: 419
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00370802

✦ Synopsis

The contribution of possible ionic conductances to the membrane potential (E~ of ceils in guinea-pig small intestinal crypts has been studied using the nystatin "perforated-patch" approach in current-clamp experiments. Changes in extracellular K + produced shifts in Era, with a 37 mV change in potential per ten-fold increase in extracellular K + concentration. Reduction of extracellular CI by 130 mM led to a 7 mV hyperpolarisation while Na + replacement was without effect on Em. The mnscarinie agonist carbachol produced a hyperpolarisation which could be ascribed to an increase in basolateral K + conductance. This effect was sustained in the presence of extracellular Ca 2+ but was transient in its absence. We conclude that the conductance of the basolateral membrane of small intestinal crypts is mainly K + selective and can be reversibly increased by muscarinic activation.