Researcher Database



FacultyGraduate School of Medical Sciences Department of Cell Physiology
PositionAssistant Professor
Last Updated :2020/07/02

Research Activities

Published Papers

  • Characterization of peristaltic motility in the striated muscle portion of the esophagus using a novel in vivo method in rats., Horii K, Shiina T, Naitou K, Nakamori H, Horii Y, Shimaoka H, Shimizu Y, Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 31, (4) , 04 , Refereed
  • Descending monoaminergic pathways projecting to the spinal defecation center enhance colorectal motility in rats., Naitou K, Nakamori H, Horii K, Kato K, Horii Y, Shimaoka H, Shiina T, Shimizu Y, American journal of physiology. Gastrointestinal and liver physiology, 315, (4) G631 - G637, 10 , Refereed
  • Induction of hibernation-like hypothermia by central activation of the A1 adenosine receptor in a non-hibernator, the rat., Shimaoka H, Kawaguchi T, Morikawa K, Sano Y, Naitou K, Nakamori H, Shiina T, Shimizu Y, The journal of physiological sciences : JPS, 68, (4) 425 - 430, 07 , Refereed
  • Colokinetic effect of somatostatin in the spinal defecation center in rats., Naitou K, Shiina T, Nakamori H, Sano Y, Shimaoka H, Shimizu Y, The journal of physiological sciences : JPS, 68, (3) 243 - 251, 05 , Refereed
  • Local regulatory mechanism to coordinate colorectal motility in rats., Sawada R, Nakamori H, Naitou K, Horii K, Horii Y, Shimaoka H, Shiina T, Shimizu Y, Physiological reports, 6, (10) , 05 , Refereed
  • Exogenous serotonin regulates colorectal motility via the 5-HT2and 5-HT3receptors in the spinal cord of rats, H. Nakamori, K. Naitou, Y. Sano, H. Shimaoka, T. Shiina, Y. Shimizu, Y. Shimizu, Neurogastroenterology and Motility, 30, 03 01 , © 2017 John Wiley & Sons Ltd Background: We previously reported that intrathecal injection of noradrenaline or dopamine causes enhancement of colorectal motility. As these monoamines are neurotransmitters of descending pain inhibitory pathways in the spinal cord, we hypothesized that serotonin, which is one of the neurotransmitters involved in descending pain inhibition, also influences the lumbosacral defecation center. Therefore, we examined whether serotonin acting on the spinal defecation center enhances colorectal motility. Methods: Colorectal intraluminal pressure and propelled liquid volume were recorded in vivo in anesthetized rats. Key Results: Intrathecal injection of serotonin into the L6-S1 spinal cord elicited periodic increases in colorectal intraluminal pressure, being associated with increases in liquid output. Pharmacological experiments revealed that the effect of serotonin is mediated by both 5-HT2and 5-HT3receptors. The serotonin-induced enhancement of colorectal motility was unaffected even after disconnection of the defecation center from supraspinal regions by cutting the T8 spinal cord, while transection of the parasympathetic pelvic nerves prevented the colokinetic effect of serotonin. Finally, we investigated interactions among serotonin, noradrenaline and dopamine. Simultaneous administration of sub-effective doses of these monoamine neurotransmitters into the spinal cord caused propulsive colorectal motility slightly but substantially. Conclusions and Inferences: These results demonstrate that exogenous serotonin acts on 5-HT2and 5-HT3receptors in the lumbosacral defecation center and activates the parasympathetic nervous system to enhance colorectal motility in cooperation with noradrenaline and dopamine.

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