Po‑Chun Hsieha, Shang‑Jen Changb,c, Hsi‑Hsien Changb, Stephen Shei‑Dei Yangb,d*
aDepartment of Chinese Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan, bDivision of Urology, Department of Surgery, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan, cDepartment of Urology, National Taiwan University Hospital, Taipei, Taiwan, dSchool of Medicine, Tzu Chi University, Hualien, Taiwan
Open Access funded by Buddhist Compassion Relief Tzu Chi Foundation
Abstract
Objectives: The bladder and urethra work as a physiologically functional unit to facilitate continence in the storage and voiding phase. Sex differences have been found in the urethral contraction in response to α‑adrenergic receptor activation. This study aimed to investigate the role of adrenergic receptors in the proximal urethra of male and female mice. Materials and Methods: Urinary bladder and proximal urethral smooth muscle (USM) samples from male and female C57BL/6 mice were isolated and mounted in an organ bath. Results: Acetylcholine‑induced contraction of the urinary bladder was compared in male and female mice. Phenylephrine and norepinephrine (NE) induced little contraction at a lower concentration, but a relaxing phase of female proximal USM was observed at a higher concentration. This contraction profile was inhibited by NG‑nitro‑L‑arginine, lidocaine, and capsaicin. In addition, the NE‑induced contraction was greater in the incubation of propranolol than that of L‑NNA or lidocaine. These results suggested that the β‑adrenoceptor may be the dominant receptor of female proximal USM, and the activity of calcitonin gene‑related peptide sensory nerves and nitrergic nerves may pose an anti‑contraction effect on the proximal urethra in female mice. Conclusion: β‑adrenoceptor may be the dominant receptor of female proximal USM. The use of β‑adrenergic receptor blocker agents might have the potential for the treatment of female voiding dysfunction.
Keywords: Adrenoceptor, Proximal urethra, Sex differences
