Acute cold exposure induces vagally mediated Fos expression in gastric myenteric neurons in conscious rats.
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.
Yuan
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CURE: Digestive Diseases Research Center, Department of Veterans Affairs Greater Los Angeles Healthcare System, and Digestive Diseases Division, University of California, Los Angeles, California 90073, USA.
Taché
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Y
Miampamba
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M
Yang
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H
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001949:Bretylium Compounds / Q000494:pharmacology; D003080:Cold Temperature; D003243:Consciousness; D005753:Gastric Mucosa / Q000378:metabolism; D018738:Hexamethonium / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009197:Myenteric Plexus / Q000187:drug effects / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000032:analysis; D009474:Neurons / Q000737:chemistry / Q000378:metabolism; D018733:Nicotinic Antagonists / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000294:innervation*; D014629:Vagotomy, Proximal Gastric; D014630:Vagus Nerve / Q000502:physiology*
D001949:Bretylium Compounds; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D016760:Proto-Oncogene Proteins c-fos; D018738:Hexamethonium; D001285:Atropine; D009252:NADPH Dehydrogenase; C045166:bretylium