The effect of antisecretory factor on the permeability of nerve cell membrane to chloride ion

The antisecretory factor (ASF) is a hormone-like protein (m.w. 60,000) that most effectively counteracts hypersecretion in vivo in the small intestine of pigs and rats. The present report demonstrate that 10(-13) moles of ASF inhibits significantly the 36Cl- permeation through the isolated neuronal plasma membrane of Deiters' cells in rabbits. This effect was enhanced by 0.2 mM gamma-aminobutyric acid (GABA), and quenched by the addition of anti-ASF immunoglobulins; pretreatment of the neuronal membrane with nipecotic acid (10(-6) M) or with bicuculline (10(-3) M) abolished the ASF action whilst picrotoxin (10(-4) M) pretreatment left the inhibitory effect of ASF unaffected. The results suggest that ASF blocks chloride channels in neuronal membranes, including those channels activated by GABA.