Urinary Bladder Response to Unilateral Stimulation of Hypogastric Nerves

Abstract

Unilateral stimulation of hypogastric nerves in adult cats always elicited on the corresponding side a prompt contraction of all portions of the detrusor muscle which was followed immediately by relaxation in the same regions. On the opposite side slightly over 1/2 of the responses, following unilateral stimulation of hypogastric nerves, were similar to those observed on the stimulated side. Another group of responses had a latent period of from 1 to 4 seconds before the onset of contraction. Sectioning of the nerves and excitation of their distal cut ends had a tendency to lengthen the latent period. In the remainder of the responses elicited from the contralateral side the initial reaction was one of relaxation. In some regions this was followed by contraction and subsequent relaxation, in others, relaxation was the only response. The amount of contraction per unit length of muscle in response to unilateral stimulation varied within wide limits in the same and different bladders. Sectioning of the nerves or altering the intravesical pressure did not materially affect the result. The average amount of contraction on the homolateral side always exceeded that obtained from the opposite side. The least responsive areas in any single observation were on the contralateral side, generally along the lateral margin and adjacent to or, within, the fundic portion of the bladder. These studies indicate a much more extensive bilateral innervation of the detrusor muscle by hypogastric nerves than was previously suggested. All areas of the bladder wall were found to be supplied by each hypogastric nerve but the richness of this innervation was quite variable, especially on the contra-lateral side, near the lateral margin of the viscus.