Tadalafil, a phosphodiesterase type 5 inhibitor, restores urethra and detrusor function in the initial phase of diabetes in rats.
OBJECTIVE
This study investigated the effects of tadalafil on the urethra and detrusor in the initial phase of diabetes in rats.


METHODS
Thirty-six female Sprague-Dawley rats were assigned to a non-diabetes (ND), diabetes (D), or tadalafil-treated diabetes (DT) group (n = 12 per group), with the DT group receiving oral tadalafil (2 mg/kg/d) for 7 days before the experiments. Seven weeks after diabetes induction (by a single intraperitoneal injection of streptozotocin), urethral and intravesical pressure were simultaneously recorded in vivo, whereas responses of detrusor strips to potassium chloride (30 mM), electrical field stimulation (EFS) and carbachol were measured in vitro.


RESULTS
The intravesical pressure at which the urethra started to relax was significantly lower in the DT than D group (mean [± s.d.] 18.9 ± 2.9 vs 29.1 ± 6.6 cm H2 O; P < .05). In addition, the reduction in urethral pressure was significantly larger in the DT than D group (-10.9 ± 4.0 vs -4.0 ± 2.9 cm H2 O; P < .05). Detrusor stimulation revealed that the mean contractile responses to EFS and carbachol were significantly lower in the ND and DT groups than in the D group (120.7 ± 26.5% and 130.8 ± 15.8% vs 200.1 ± 47.9% of the 30 mM KCl-induced contraction, respectively, in response to 50 Hz EFS [P < .05]; 211.1 ± 35.4% and 208.4 ± 25.3% vs 425.7 ± 125.0% of the 30 mM KCl-induced contraction, respectively, in response to 10-3 M carbachol [P < .05]).


CONCLUSIONS
Tadalafil restored urethral relaxation function and detrusor responses to EFS and carbachol during the initial phase of diabetes.
['Gotoh|Daisuke|D|https://orcid.org/0000-0002-6056-3820', 'Torimoto|Kazumasa|K|https://orcid.org/0000-0003-2870-0466', 'Iwasaki|Hirotaka|H|', 'Iwamoto|Takashi|T|', 'Morizawa|Yosuke|Y|', 'Hori|Shunta|S|', 'Miyake|Makito|M|', 'Tanaka|Nobumichi|N|', 'Hirayama|Akihide|A|', 'Nishi|Eiichiro|E|', 'Fujimoto|Kiyohide|K|']
D000818:Animals D002217:Carbachol D003921:Diabetes Mellitus, Experimental D004558:Electric Stimulation D005260:Female D009119:Muscle Contraction D009130:Muscle, Smooth D058986:Phosphodiesterase 5 Inhibitors D051381:Rats D017207:Rats, Sprague-Dawley D000068581:Tadalafil D014521:Urethra D001743:Urinary Bladder
tadalafil urethra detrusor diabetes rat phosphodiesterase 5