[Vesicourethral physiology during continence and urination in cats. In vivo and in vitro studies].
The mechanisms implicated in the opening of the bladder neck during voiding are still controversial. We present a study of the reflexes of bladder, urethra and periurethral striated muscles in the cat. The study in vivo shows that a passive muscle tonus of the urethra is able to maintain the continence. During voiding, opening of the bladder outlet is done actively: contraction of the longitudinal and relaxation of the circular muscle layers of the urethra associated with detrusor contraction. There is a local reflex between the urethra, bladder and periurethral striated muscles that completes emptying of the bladder with an interrupted stream. The study in vitro confirms that the 2 muscle layers of the urethra have different innervation: the parasympathomimetic agents act on the longitudinal layer and very weakly on the circular. Both layers react to adrenergic stimulation.
D000818:Animals; D001626:Bethanechol Compounds / Q000494:pharmacology; D002415:Cats; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D014521:Urethra / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D001743:Urinary Bladder / Q000033:anatomy & histology / Q000502:physiology*; D014554:Urination
D001626:Bethanechol Compounds; D010656:Phenylephrine
La physiologie vésico-urétrale pendant la continence et la miction chez le chat. Etudes in vivo et in vitro.