Abstract
An electrophysiological investigation of nerve pathways was performed on the chicken's isolated rectal region of Remak's nerve trunk and isolated perfused rectum with attached Remak's nerve supply. Compound action potentials were recorded using the sucrose gap method. The rectal region of Remak's nerve trunk was found to consist of four groups of nerve pathways composing of B and C fibers, according to the conduction velocity of nervous impulses. Some of them involved synaptic transmission somewhere in the trunk. Present results also provided evidence for the existence of nerve pathways innervating the rectum: (1)that was to ascend or descend in Remak's nerve trunk, leave the trunk and run in the branches to the rectum, (2)that was to descend splanchnic lumbosacral nerve, enter Remak's nerve trunk, leave the trunk, and run in the branches to the rectum, and (3)that was to ascend the branches, enter Remak's nerve trunk, leave the trunk, and run in the branches to the recturm (a local reflex arch). It seemed very likely that these nerve pathways innervating the rectum were excitatory and mediate non-cholinergic, non-adrenergic responses in the rectum.
