PURPOSE: To examine whether there are sex-related differences in urinary bladder function, we evaluated the function and distribution of beta-adrenoceptor in the male and female rabbit urinary bladder. MATERIALS AND METHODS: Ten male and ten female rabbits were studied. The function and distribution of beta-adrenoceptors were studied by measuring changes in contractile forces from isoproterenol, a beta-adrenoceptor agonist, and forskolin, an adenylate cyclase activator, and by measuring beta-adrenoceptor densities using radioligand receptor binding techniques. RESULTS: Isoproterenol caused significantly greater relaxation in female trigonal muscles than in male trigonal muscles. It caused similar relaxation responses in the male and female detrusors. The Bmax values for [3H]dihydroalprenolol (DHA) binding in trigonal muscles were significantly higher in the female than in the male, whereas Bmax values for [3H]DHA binding in the male and the female detrusor were similar. In contrast, forskolin caused similarly marked relaxations in the male and the female detrusor and trigonal muscles. CONCLUSION: These findings demonstrate that there are sex-related differences in the function and the distribution of beta-adrenoceptors in rabbit trigonal smooth muscles.
PURPOSE: To examine whether there are sex-related differences in urinary bladder function, we evaluated the function and distribution of beta-adrenoceptor in the male and female rabbit urinary bladder. MATERIALS AND METHODS: Ten male and ten female rabbits were studied. The function and distribution of beta-adrenoceptors were studied by measuring changes in contractile forces from isoproterenol, a beta-adrenoceptor agonist, and forskolin, an adenylate cyclase activator, and by measuring beta-adrenoceptor densities using radioligand receptor binding techniques. RESULTS:Isoproterenol caused significantly greater relaxation in female trigonal muscles than in male trigonal muscles. It caused similar relaxation responses in the male and female detrusors. The Bmax values for [3H]dihydroalprenolol (DHA) binding in trigonal muscles were significantly higher in the female than in the male, whereas Bmax values for [3H]DHA binding in the male and the female detrusor were similar. In contrast, forskolin caused similarly marked relaxations in the male and the female detrusor and trigonal muscles. CONCLUSION: These findings demonstrate that there are sex-related differences in the function and the distribution of beta-adrenoceptors in rabbit trigonal smooth muscles.