[Roles of prostaglandin on rabbit vesicourethral smooth muscle contraction].
The effects of prostaglandin (PG) E1, E2 and F2 alpha on isolated smooth muscles of rabbit bladder and urethra were studied by in vitro techniques for recording contractile activities. To examine the mechanism of PGs' effect, intracellular cyclic AMP content was also measured by radioimmunoassay. Spontaneous contractile force of muscle strips isolated from rabbit urinary bladder dome and base was increased dose-dependently by administration of PGE1, E2 or F2 alpha. Isolated muscle strips from bladder dome responded to PG more markedly than those from bladder base. The rank order of potency to induce contractile responses was PGF2 alpha greater than PGE2 greater than PGE1 in both dome and base muscles. Spontaneous contractile force of muscle strips isolated from rabbit urethra was increased dose-dependently by administration of PGF2 alpha, and, in contrast, was decreased dose-dependently by PGE1 or E2. These effects were not affected by pretreatment with atropine, phentolamine, propranolol and tetrodotoxin, but were significantly inhibited by pretreatment with verapamil, a Ca-antagonist. Cyclic AMP accumulation in urethral muscle strips significantly increased after administration of PGE1. These results demonstrated that contractile response of rabbit bladder smooth muscle to PG was mainly induced by Ca2+ influx and that cyclic AMP was related to the relaxation of rabbit urethral smooth muscle by PGE1.
Hanawa
A
A
Department of Urology, Akita University School of Medicine.
D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D015237:Dinoprost / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D011453:Prostaglandins / Q000494:pharmacology / Q000502:physiology*; D011458:Prostaglandins E / Q000502:physiology; D011817:Rabbits; D014521:Urethra / Q000737:chemistry / Q000187:drug effects; D001743:Urinary Bladder / Q000737:chemistry / Q000187:drug effects
D011453:Prostaglandins; D011458:Prostaglandins E; D015237:Dinoprost; D000242:Cyclic AMP