Abstract
Isolated strips of the guinea-pig's small intestine were stimulated by local application of electrical impulses or of histamine. The local excitations were conducted in the intestinal wall in an oral as well as in an aboral direction and resulted in contractions of the intestine which varied in strength with the intensity of local stimulation. It was concluded from the observed effects of hexamethonium, cocaine, atropine, and morphine on these contractions that three different mechanisms may be concerned in the conduction of local excitations: 1. Preganglionic fibres which at low frequencies conduct preferably in an oral direction. Excitation along these fibres is mediated by ganglion cells and can be blocked by hexamethonium and low concentrations of cocaine. 2. Postganglionic structures which conduct equally well in both directions. The effects of their stimulation can be abolished by atropine and morphine. 3. A muscular syncytium in which the conduction of excitations is unaffected by autonomic blocking drugs.
Published Version
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