Method for Simultaneous Recording of the Prostatic Contractile and Urethral Pressure Responses in Anesthetized Rats and the Effects of Tamsulosin

Abstract

We simultaneously recorded the prostatic contractile and urethral pressure responses to electrical stimulation (ES) of the hypogastric nerves (HGNs) or phenylephrine in anesthetized rats and studied the effects of tamsulosin on these responses. At 0.01 and 0.1 mg/kg, i.v., tamsulosin inhibited the prostatic responses to ES of the HGNs in a dose-dependent manner, while at 1 microg/kg, i.v., it reduced the response to phenylephrine (0.01 mg/kg, i.v.) to about 26% of the nonantagonized level. These inhibitory effects on prostatic responses were maintained for 60 min. Tamsulosin exerted an inhibitory effect on the urethral response to ES of the HGNs at 0.01 mg/kg, i.v. but not at 0.1 mg/kg, i.v. At 1 microg/kg, i.v., tamsulosin also reduced the urethral response to phenylephrine to about 46% of the nonantagonized level; this effect was maintained for 60 min. Furthermore, tamsulosin was found to exert a stronger inhibitory effect on the prostatic response than on the urethral response induced by sympathetic nerve activation. Our findings suggest that rat urethral sympathetic nerve terminals may contain prejunctional alpha1 adrenoceptors that modulate the release of norepinephrine.

Implication of Rho‐kinase and soluble guanylyl cyclase enzymes in prostate smooth muscle dysfunction in middle‐aged rats

“…The in vivo prostate tension was evaluated according to a previous study . Briefly, rats were anesthetized with urethane (1.8 g/kg, ip), and the prostate was exposed through a midline abdominal incision.…”

Slimmer or Fertile? Pharmacological Mechanisms Involved in Reduced Sperm Quality and Fertility in Rats Exposed to the Anorexigen Sibutramine

“…The in vivo prostate tension was evaluated as described by Kontani & Shiraoya [33]. Adult male rats (120 days old, 500 g weight) were anesthetized with urethane (1.5 g/kg, sc) and the prostate ventral lobes were tied with a cotton thread and attached to an isometric force transducer under 9.8 mN resting tension.…”

Pharmacology for the Treatment of Premature Ejaculation

“…In various mammals, including humans, semen can be obtained by stimulation of the sympathetic and parasympathetic nerves destined for ejaculatory tissues (Watanabe et al, 1988;Brindley et al, 1989;Kolbeck and Steers, 1992;Kontani and Shiraoya, 2002). Traumatic or postsurgical disruption of sympathetic pathways innervating the seminal tract is a cause of ejaculatory dysfunction (anejaculation or retrograde ejaculation) in men (May et al, 1969;Pocard et al, 2002).…”

“…Both ␣ 1 -and ␣ 2 -adrenoreceptors have been identified in urethra of various species, being mainly located in smooth muscle cells (␣ 1 ) and submucosa (␣ 2 ) (Monneron et al, 2000). Pharmacological investigations showed that contractions of the seminal tract and accessory sex glands elicited by sympathomimetic agents were blocked, at least partially, by ␣ 1 -adrenoreceptor antagonists (Stjernquist et al, 1983;Terasaki, 1989;Kolbeck and Steers, 1992;Kontani and Shiraoya, 2002). Cholinomimetic drugs are known to induce contraction of sex glands through stimulation of muscarinic receptors (Lepor and Kuhar, 1984;Terasaki, 1989).…”