Relative contributions of smooth and striated muscles to the canine urethral pressure profile.

Canine urethral pressure profiles were analysed using pharmacological and nerve sectioning techniques. The presence of significant sympathetic and somatic neural components was detected and their locations along the proximal urethra were identified. The neural components peaked at different points in the urethra but overlapped. The non-neural component appeared to form an even base along the whole proximal urethra. It was concluded that in the proximal part of the profile the non-neural and the sympathetic components are significant. The sympathetic component becomes larger in the peak pressure zone. More distally and overlapping with the sympathetic component is the contribution of the striated external sphincter.