title: Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation: An in vivo microdialysis study.
abstract: To elucidate the possible involvement of glutamate and serotonin (5-hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation.
  
  
  
  The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5-hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid-induced cystitis were determined using in vivo microdialysis combined with cystometry in rats.
  
  
  
  Extracellular glutamate levels slightly, but significantly, increased during the micturition reflex induced by saline infusion into the bladder. Intravesical infusion of acetic acid facilitated the micturition reflex characterized by increases in voiding pressure and decreases in the intercontraction interval. Glutamate levels were markedly increased by acetic acid, and this enhancement was sustained for at least 3 h. 5-Hydroxytryptamine levels, which were not altered during the micturition reflex, were increased after intravesical infusion of acetic acid.
  
  
  
  The results suggest that periaqueductal gray glutamate and 5-hydroxytryptamine neurons differentially participate in the modulation of both nociception and the micturition reflex. Furthermore, periaqueductal gray 5-hydroxytryptamine levels appear to reflect the nociceptive stimuli.
authors.affiliation: Department of Renal and Genitourinary Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Takeya
authors.initials: T
authors.lastname: Kitta
authors.affiliation: Department of Urology, Yamanashi University, Yamanashi, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Mitsui
authors.affiliation: Department of Renal and Genitourinary Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kanno
authors.affiliation: Department of Renal and Genitourinary Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Chiba
authors.affiliation: Department of Renal and Genitourinary Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Moriya
authors.affiliation: Department of Neuropharmacology, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshioka
authors.affiliation: Department of Renal and Genitourinary Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Shinohara
mesh_terms: D000818:Animals; D003556:Cystitis; D004195:Disease Models, Animal; D017551:Microdialysis; D018377:Neurotransmitter Agents / Q000502:physiology*; D010487:Periaqueductal Gray / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex; D014554:Urination / Q000502:physiology*
chemical_list: D018377:Neurotransmitter Agents
keywords: cystitis; glutamate; micturition reflex; periaqueductal gray; serotonin