[Alpha adrenergic mechanism on the reflex micturition in the male decerebrate dog].
We investigated the alterations of urodynamic parameters of reflex micturition evoked by filling the bladder with physiological saline prior to and after the administration of midodrine (alpha 1 agonist), terazosin (alpha 1 antagonist), clonidine (alpha 2 agonist) and yohimbine (alpha 2 antagonist) in 28 male decerebrate dogs. The significant finding produced by midodrine was an increase in contraction pressure, while terazosin produced a significant decrease in threshold pressure, contraction pressure and urethral pressure. Clonidine produced a decrease in threshold pressure, urethral pressure and external urethral sphincter activity, while yohimbine produced a significant increase in bladder volume and urethral pressure. It seems that alpha 1 adrenergic activity modulates urethral closing pressure via postsynaptic alpha 1 receptors, and that alpha 2 adrenergic activity mainly modulates urethral closing pressure via presynaptic alpha 2 receptors in the lower urinary tract function.
Takahashi
T
T
Department of Urology, Akita University School of Medicine.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D003655:Decerebrate State / Q000503:physiopathology*; D004285:Dogs; D008297:Male; D008365:Manometry; D008879:Midodrine / Q000494:pharmacology; D011224:Prazosin / Q000031:analogs & derivatives / Q000494:pharmacology; D012018:Reflex / Q000187:drug effects*; D014521:Urethra / Q000502:physiology; D001743:Urinary Bladder / Q000502:physiology; D014554:Urination / Q000187:drug effects*; D014563:Urodynamics / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D015016:Yohimbine; D008879:Midodrine; C041226:Terazosin; D003000:Clonidine; D011224:Prazosin