Hypogastric Nerve of the Dog

Abstract

EXPERIMENTS attempting to distinguish between the effects of reserpine on sympathetic ganglia and on postganglionic fibres were carried out on the inferior mesenteric ganglia and the hypogastric nerves of the dog. Analysis of the tissues showed such large and variable amounts of both noradrenaline and adrenaline in the hypogastric ‘nerves’, coupled with a high degree of resistance to the depleting effect of reserpine, that it was obvious that these ‘nerves’ were complex in structure. Langley and Anderson's detailed analysis¹ of the hypogastric nerves of the cat and the rabbit had shown these to consist of about 90 per cent non-medullated and 10 per cent (afferent) medullated fibres. As these authors pointed out later², a proportion of the non-medullated fibres are preganglionic and are interrupted in ganglia situated usually near the innervated organ, such ganglia being more frequent in the rabbit than in then cat. This analysis did not, however, explain the chemical findings on catecholamines in the dog, since these strongly suggested the presence of chromaffine tissue in the nerves.