Nonadrenergic inhibition of human intestinal smooth muscle

Abstract

The effects of ATP, α,β-methylene-ATP, α,γ-methylene-ATP and adenosine on longitudinal and circular smooth muscle of the human large and small intestine were investigated using the sucrose gap technique. Applications of ATP to the smooth intestinal muscle produced an effect resembling that of stimulating the nonadrenergic nerve fibers in most cases. Desensitization of the purinoreceptors by α,β-methylene-ATP selectively reduced the amplitude of nonadrenergic inhibitory synaptic potentials. The findings presented confirm the purinergic hypothesis of nonadrenergic inhibition in the smooth muscle of human intestine.