title: Pharmacological effect of amezinium on urethra and bladder of rabbits.
abstract: The pharmacological effect of amezinium on the urethra and bladder of rabbits was investigated. Amezinium produced concentration-dependent contractions in isolated urethral strips. The maximum response was approximately 30% of that caused by norepinephrine (NE). The concentration-response curve of NE was shifted to the left by amezinium. Moreover, amezinium enhanced the relaxative effect of NE on carbachol-induced contractions in isolated bladder strips. In anesthetized rabbits, amezinium significantly increased the intraurethral pressure (IUP) but produced only slight increases in mean blood pressure (MBP). Pre-treatment with amezinium ehhanced NE-induced increases in IUP index and MBP. The enhancing effect on the IUP index lasted much longer than that on MBP. In a stress incontinence model amezinium significantly inhibited the incontinence after an i.v. infusion of a low dose of NE. This effect was antagonized by pre-treatment with prazosin. These results suggest that amezinium may produce an excellent effect for stress incontinence, especially mixed, without severe adverse events such as sudden hypertension.
authors.affiliation: Department of Pharmacology 1, Dainippon Pharmaceutical Co. Ltd, Suita, Osaka, Japan. isao-shimizu@dainippon-pharm.co.jp
authors.forename: I
authors.initials: I
authors.lastname: Shimizu
authors.forename: D
authors.initials: D
authors.lastname: Ishii
authors.forename: K
authors.initials: K
authors.lastname: Kawashima
authors.forename: M
authors.initials: M
authors.lastname: Oka
authors.forename: K
authors.initials: K
authors.lastname: Hosoki
mesh_terms: D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D011724:Pyridazines / Q000494:pharmacology*; D011817:Rabbits; D013566:Sympathomimetics / Q000494:pharmacology*; D014521:Urethra / Q000187:drug effects*; D001743:Urinary Bladder / Q000187:drug effects*
chemical_list: D011724:Pyridazines; D013566:Sympathomimetics; C027784:amezinium