INTRINSIC URETHRAL CLOSURE MECHANISMS IN THE FEMALE PIG

This study investigates the role of the various components of the fema le pig urethral wall in the generation of the urethral closure pressur e. Prior to voiding urethral pressure falls and this is accompanied by a rise in lamina propria blood how. Pharmacological manipulation show s that striated muscle is not involved in the generation of the urethr al closure pressure. Drugs active upon smooth muscle change urethral p ressure significantly by a mechanism independent of their cardiovascul ar system effects. Histological studies show that it is possible to co rrelate the disposition of circular smooth muscle with the urethral pr essure profile. In vitro smooth muscle from the high pressure zone is pharmacologically different to that from the proximal urethra in a man ner which may reflect their physiological roles.