title: Regulatory Effects of 5-Hydroxytryptamine Receptors on Voiding Function.
abstract: A growing body of evidence suggests that 5-hydroxytryptamine (5-HT; serotonin) has both physiological and pathological functions in the lower urinary tract. A wide variety of 5-HT receptor subtypes are variably expressed in different organs, both peripheral and central. On urinary bladder smooth muscle, 5-HT1A, 5-HT2, 5-HT3, and 5-HT7 subtypes could function as postjunctional receptors. Postjunctional 5-HT2 receptors induce detrusor contraction of the bladder body. 5-HT1A is suggested to have a similar effect to 5-HT2, while 5-HT3 might suppress detrusor contraction evoked by direct muscle stimulation. Postjunctional 5-HT7 is reported to induce relaxation of the bladder neck, which might be required for efficient voiding. 5-HT1A, 5-HT2A, 5-HT2C, 5-HT3, 5-HT4, and 5-HT7 subtypes also could act as prejunctional receptors in autonomic excitatory nerve terminals. 5-HT2A, 5-HT2C, 5-HT3, 5-HT4, and 5-HT7 subtypes facilitate the neurogenic contraction of the detrusor by enhancing cholinergic or purinergic transmission, whereas 5-HT1A receptors might inhibit the release of acetylcholine in the detrusor. Furthermore, 5-HT1D could be involved in the suppression of ATP release from the urothelium, aiding visceral sensation of the urinary bladder. In the central pathways controlling the micturition reflex, 5-HT1A, 5-HT2A, and 5-HT7 are involved in regulation of bladder and urethral sphincter activities. Their functions, especially that of 5-HT1A, vary in a species- and site (spinal or supraspinal)- dependent manner. In addition to urinary bladder, 5-HT could be involved in prostate contraction and cell proliferation. Evidence indicates that 5-HT receptor subtypes may be novel therapeutic targets for lower urinary tract symptoms.
  
  
  BACKGROUND
  Grants-in-Aid for Scientific Research (C) (KAKENHI 23590707, 24590722, and 26460694) from the Japan Society for the Promotion of Science.
authors.affiliation: Department of Neurophysiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, Akita, 010-8543, Japan. k.miyai@kki.ac.jp.|Kansai University of Nursing and Health Sciences, 1456-4 Shizuki, Awaji, Hyogo, 656-2131, Japan. k.miyai@kki.ac.jp.|Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan. k.miyai@kki.ac.jp.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Matsumoto-Miyai
authors.affiliation: Department of Neurophysiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, Akita, 010-8543, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Yoshizumi
authors.affiliation: Department of Neurophysiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, Akita, 010-8543, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Kawatani
mesh_terms: D000818:Animals; D006801:Humans; D011985:Receptors, Serotonin / Q000145:classification / Q000502:physiology; D012701:Serotonin / Q000378:metabolism*; D014551:Urinary Tract / Q000378:metabolism / Q000503:physiopathology; D014553:Urinary Tract Physiological Phenomena
chemical_list: D011985:Receptors, Serotonin; D012701:Serotonin
keywords: 5-HT receptor subtypes; 5-Hydroxytryptamine; Lower urinary tract; Micturition reflex