Pharmacological effect of amezinium on urethra and bladder of rabbits.
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.
Shimizu
I
I
Department of Pharmacology 1, Dainippon Pharmaceutical Co. Ltd, Suita, Osaka, Japan. isao-shimizu@dainippon-pharm.co.jp
Ishii
D
D
Kawashima
K
K
Oka
M
M
Hosoki
K
K
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*
D011724:Pyridazines; D013566:Sympathomimetics; C027784:amezinium