title: Effect of chemical stimulation of the medial frontal lobe on the micturition reflex in rats.
abstract: OBJECTIVE
  We assessed the influence of the medial frontal lobe on micturition after chemical stimulation. We also examined the relation between the medial frontal lobe and the rostral pontine reticular formation, which has a strong inhibitory effect on micturition.
  
  
  METHODS
  A total of 35 female rats underwent continuous cystometry. Bladder activity changes were examined after physiological saline, glutamate, the glutamate receptor antagonist MK-801, noradrenaline or the adrenergic α-1 receptor antagonist naftopidil was injected in the medial frontal lobe. When glutamate was injected in the medial frontal lobe, MK-801 was also injected in the rostral pontine reticular formation.
  
  
  RESULTS
  Glutamate injection in the medial frontal lobe prolonged the interval between bladder contractions while injection of the glutamate antagonist MK-801 shortened the interval. Glutamate injection in the medial frontal lobe just after MK-801 injection in the ipsilateral rostral pontine reticular formation also prolonged the interval between bladder contractions. However, after prior injection of MK-801 in the bilateral rostral pontine reticular formation glutamate injection in the medial frontal lobe did not influence cystometric parameters. Noradrenaline injection in the medial frontal lobe shortened the interval between bladder contractions while injection of its antagonist naftopidil prolonged the interval.
  
  
  CONCLUSIONS
  Medial frontal lobe neurons excited by glutamate inhibited the micturition reflex via activation of the rostral pontine reticular formation by glutamatergic projection while medial frontal lobe neurons excited by noradrenaline facilitated the micturition reflex. Thus, the medial frontal lobe may be an important integration center for the initiation of micturition and urine storage mechanisms.
authors.affiliation: Southern Knights' Laboratory, L.L.P. and Department of Biochemistry, Graduate School of Medicine, University of the Ryukyus (HY), Okinawa, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Nishijima
authors.forename: Kimio
authors.initials: K
authors.lastname: Sugaya
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kadekawa
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Ashitomi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D016291:Dizocilpine Maleate / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D007267:Injections; D011149:Pons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology*; D013268:Stimulation, Chemical; D014554:Urination / Q000502:physiology*
chemical_list: D018698:Glutamic Acid; D016291:Dizocilpine Maleate