Acute cold exposure induces vagally mediated Fos expression in gastric myenteric neurons in conscious rats

Am J Physiol Gastrointest Liver Physiol. 2001 Aug;281(2):G560-8. doi: 10.1152/ajpgi.2001.281.2.G560.

Abstract

Acute cold exposure-induced activation of gastric myenteric neurons in conscious rats was examined on longitudinal muscle-myenteric plexus whole mount preparations. Few Fos-immunoreactive (IR) cells (<1/ganglion) were observed in 24-h fasted rats semirestrained at room temperature. Cold exposure (4 degrees C) for 1-3 h induced a time-related increase of Fos-IR cells in corpus and antral myenteric ganglia with a maximal plateau response (17 +/- 3 and 18 +/- 3 cells/ganglion, respectively) occurring at 2 h. Gastric vagotomy partly prevented, whereas bilateral cervical vagotomy completely abolished, Fos expression in the myenteric cells induced by cold exposure (2 h). Hexamethonium (20 mg/kg) also prevented 3-h cold exposure-induced myenteric Fos expression by 76-80%, whereas atropine or bretylium had no effect. Double labeling revealed that cold (3 h)-induced Fos-IR myenteric cells were mainly neurons, including a substantial number of choline acetyltransferase-containing neurons and most NADPH-diaphorase-positive neurons. These results indicate that acute cold exposure activates cholinergic as well as nitrergic neurons in the gastric myenteric ganglia through vagal nicotinic pathways in conscious rats.

Publication types

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

MeSH terms

  • Animals
  • Atropine / pharmacology
  • Bretylium Compounds / pharmacology
  • Cold Temperature*
  • Consciousness
  • Gastric Mucosa / metabolism
  • Hexamethonium / pharmacology
  • Muscarinic Antagonists / pharmacology
  • Myenteric Plexus / drug effects
  • Myenteric Plexus / metabolism*
  • NADPH Dehydrogenase / analysis
  • Neurons / chemistry
  • Neurons / metabolism
  • Nicotinic Antagonists / pharmacology
  • Proto-Oncogene Proteins c-fos / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Stomach / innervation*
  • Vagotomy, Proximal Gastric
  • Vagus Nerve / physiology*

Substances

  • Bretylium Compounds
  • Muscarinic Antagonists
  • Nicotinic Antagonists
  • Proto-Oncogene Proteins c-fos
  • Hexamethonium
  • Atropine
  • NADPH Dehydrogenase
  • bretylium