Alpha1-adrenoceptors are required for normal male sexual function

Area of Science:

• Pharmacology
• Urology
• Reproductive Biology

Background:

• Alpha(1)-adrenoceptor antagonists are widely used for hypertension and benign prostatic hyperplasia.
• Ejaculatory dysfunction is a common side effect, particularly with alpha(1A)-selective antagonists.
• This suggests a role for alpha(1A)-adrenoceptors in ejaculation, though not previously studied at a molecular level.

Purpose of the Study:

• To investigate the physiological role of alpha(1)-adrenoceptor subtypes in ejaculation.
• To determine the contribution of alpha(1A)-adrenoceptors to vas deferens function and fertility.

Main Methods:

• Utilized alpha(1)-adrenoceptor subtype-selective knockout (KO) mice.
• Compared ejaculation, blood pressure, and vascular responses in subtype-selective KO mice and triple-KO mice.
• Assessed vas deferens contractility in response to noradrenaline and electrical stimulation.

Main Results:

• Alpha(1A)-adrenoceptor KO mice showed a 50% reduction in pregnancy rate.
• Vas deferens contractility in response to noradrenaline was significantly reduced in alpha(1A)-AR KO mice and abolished in triple-KO mice.
• Impaired contractility was also observed in electrically stimulated vas deferens.

Conclusions:

• Alpha(1)-adrenoceptors, especially alpha(1A)-subtype, are essential for normal vas deferens contractility.
• These receptors play a critical role in sperm ejaculation and male fertility.
• Findings provide molecular insights into the side effects of alpha(1)-adrenoceptor antagonists.