Importance of vagal input in maintaining gastric tone in the dog.
AUTOR(ES)
Azpiroz, F
RESUMO
1. Using a gastric barostat to quantify variations in gastric tone, we had previously demonstrated that food ingestion or intestinal nutrient perfusion induces gastric relaxation. These data suggested a basal tonic contraction of the stomach during fasting. 2. To determine the role of vagal input in maintaining fasting gastric tone, we prepared two chronic canine models, either isolating both cervical vagal trunks in a cutaneous tunnel or including the supradiaphragmatic vagi within an implanted cooling jacket. In the fasted conscious dogs, we then studied the effect, on gastric tone, of acute and reversible vagal blockade by cooling. 3. Cervical vagal cooling produced a reversible gastric relaxation and increased the heart rate. Supradiaphragmatic vagal cooling produced a similar gastric relaxation without the cardiac effect. 4. Adrenergic blockade did not change either the base-line gastric tone or the cooling-induced relaxation. Adrenaline decreased gastric tone, but vagal cooling still produced a significant relaxation. 5. Atropine alone or combined with adrenergic antagonists produced a gastric relaxation that was not further increased by vagal cooling. Bethanechol increased gastric tone, an effect unchanged by vagal cooling. 6. We conclude that gastric tone during fasting is maintained by a cholinergic input, which is vagally mediated at both the cervical and the supradiaphragmatic levels.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1192275Documentos Relacionados
- Gastric vasodilatation and vasoactive intestinal peptide output in response to vagal stimulation in the dog.
- Gastric relaxation and vasoactive intestinal peptide output in response to reflex vagal stimulation in the dog.
- Inspiratory inhibition of vagal responses to baroreceptor and chemoreceptor stimuli in the dog.
- Effect of chronic sham feeding on maximal gastric acid secretion in the dog.
- Transport of cholecystokinin-octapeptide-like immunoreactivity toward the gut in afferent vagal fibres in cat and dog.