Effects of Some Prostaglandins on Urinary Bladder and Urethra Isolated from the Dog

Abstract

Effects of prostaglandins (PGs) E₁; E₂ and F_2Α on the vesical and urethral smooth muscles of dogs were isometrically investigated in vitro. In vesical smooth muscles, 10^––8–10^––6 g PGE₁/ml produced biphasic responses in the dome preparations; relaxation at 10^––8 g/ml and contractions at 10^––7–10^––6 g/ml. In the trigone preparations, 10^––8–10^––6 g PGE₁/ml caused dose-dependent contractions. 10^––8–10^––6 g PGE₂/ml and 10^––7–10^––6 g PGF_2Α/ml induced dose-dependent contractions of the dome and the trigone preparations. In urethral smooth muscles, 10^––8–10^––6 g PGE₁/ml and 10^––8–10^––6 g PGE₂/ml produced dose-dependent relaxations, while 10^––8–10^––6 g PGF_2Α/ml caused dose-dependent contractions. Results indicate that PGE, particularly PGE₂, is able to stimulate micturition through vesical contraction and urethral relaxation.

Effects of Prostaglandins E₁ E₂ and F_2α on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

“…thra was slightly contracted by PG F2a but was not affected by PG E2. In this study the rabbit circular ure thral smooth muscle strips showed a dose-dependent relaxation to PG Ei and E2 and a dose-dependent contrac tion to PG F2a, as with those seen in the canine urethra by Mutoh et al [6], Possible reasons for differences between our results and those of Khanna et al [3] are a directional difference of muscle strips (our strips: circular; Khannas': longitudinal), and age differences in the response to PGs [9]. PG Ei, E2 and F2a contracted the rabbit urinary blad der smooth muscle strips in the present study; results which were similar with previous reports [2][3][4][5][6][7][8][9].…”

“…Ghoneim et al [10] reported that PG E2 reduced the canine urethral resistance. Mutoh et al [6] noted that the female canine urethra was relaxed by PG Ei and E2 but was contracted by PG F2a-Khanna et al [3] showed that the rabbit ure-U rina ry bladder Fig. 4.…”

Study on Physiological Roles of Stimulation of Prostaglandin E2 Receptor Subtype EP2 in Urethral Function in Rats

“…In addition to reports regarding the relaxant effect of PGE 2 in urethral tissues of various species, including hamsters, rabbits, dogs, and humans, PGE 2 has been found to reduce maximum urethral closure pressure in dogs and maximum urethral pressure in humans . However, few studies have noted any marked contribution of EP2 receptor stimulation to reduction in urethral pressure in in vivo studies.…”

Cascade Bioassay Evidence for the Existence of Urothelium-Derived Inhibitory Factor in Guinea Pig Urinary Bladder

“…One substance group to be considered is arachidonic acid derivatives from the cyclo-oxygenase system, another being the purine group including adenosine since ATP release is significant in the urothelium [6]–[9]. E-class prostaglandins are usually contractile on bladder detrusor [10], but inhibitory effects have been reported [11]. Experiments in urothelium-intact and -denuded preparations had shown that cyclo-oxygenase products had a role in regulation of ureteral motility [12].…”