Vagally-regulated gastric motor activity: evidence for kainate and NMDA receptor mediation

Eur J Pharmacol. 1999 Mar 5;368(2-3):173-82. doi: 10.1016/s0014-2999(99)00015-1.

Abstract

Blockade of GABA(A) receptors in the dorsal vagal complex produces marked gastric motor excitation. This effect is abolished by a prior microinjection of a non-selective excitatory amino acid receptor antagonist. Here we present functional evidence for kainate and NMDA receptor-mediated gastric excitation in the dorsal vagal complex. Microinjections into the dorsal vagal complex were performed in alpha-chloralose-anesthetized rats using multi-barrelled glass micropipettes while recording intragastric pressure and motility. Kainic acid (30 and 100 pmol in 30 nl) and NMDA (100 and 300 pmol) produced dose-related increases in intragastric pressure and motility. The gastric responses to kainate (30 pmol) and NMDA were selectively abolished by prior microinjection 6,7-dinitroquinoxaline-2,3-dione (600 pmol, 60 nl) and DL-2-amino-5-phosphanopentanoic acid (2 nmol), respectively. Atropine (1 mg/kg, i.v.) pretreatment blocked kainate-, NMDA- and L-glutamate-induced gastric excitation. Thus, both kainate- and NMDA-receptors in the dorsal vagal complex can independently cause vagally-mediated gastric motor excitation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Atropine / pharmacology
  • Blood Pressure / drug effects
  • Brain Stem
  • Bronchodilator Agents / pharmacology
  • Dose-Response Relationship, Drug
  • Excitatory Amino Acid Agonists / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Gastrointestinal Motility / drug effects
  • Gastrointestinal Motility / physiology*
  • Glutamic Acid / pharmacology
  • Kainic Acid / pharmacology
  • Male
  • Microinjections
  • N-Methylaspartate / pharmacology
  • Quinoxalines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology
  • Stomach / drug effects
  • Stomach / innervation
  • Stomach / physiology
  • Vagus Nerve / drug effects
  • Vagus Nerve / physiology*

Substances

  • Bronchodilator Agents
  • Excitatory Amino Acid Agonists
  • Excitatory Amino Acid Antagonists
  • Quinoxalines
  • Receptors, N-Methyl-D-Aspartate
  • Glutamic Acid
  • FG 9041
  • N-Methylaspartate
  • Atropine
  • Kainic Acid