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Neural mechanisms involved in the delay of gastric emptying of liquid elicited by acute blood volume expansion in awake rats
Author(s) -
GONDIM F. DE A. A.
Publication year - 1999
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1046/j.1365-2982.1999.00146.x
Subject(s) - hexamethonium , gastric emptying , anesthesia , endocrinology , yohimbine , atropine , medicine , guanethidine , vagus nerve , blood volume , vagotomy , chemistry , stomach , stimulation , receptor , antagonist
We have previously reported that acute blood volume expansion in awake rats delays the gastric emptying of a liquid meal, using the phenol red method. In this study we attempted to investigate the neural mechanisms involved in this phenomenon. Blood volume expansion, due to Ringer‐bicarbonate infusion up to a volume equivalent to 5% of body weight, decreased the gastric emptying of a liquid meal by half (38.2 ± 1.8 vs 18.7 ± 3.2%, P < 0.05). The blood volume expansion effect on gastric emptying of liquid was prevented by separate pretreatments, consisting of subdiaphragmatic vagotomy or i.v. injection of hexamethonium (20 mg kg −1 ) or yohimbine (3 mg kg −1 ). Intravenous injection of atropine (0.5 mg kg −1 ), guanethidine (10 mg kg −1 ), L‐NAME (3 mg kg −1 ), prazosin (1 mg kg −1 ) or propranolol (2 mg kg −1 ) did not prevent the blood volume expansion effect on gastric emptying. Bilateral adrenalectomy or coeliac ganglionectomy were also ineffective. The results indicate that blood volume expansion decreases gastric emptying of liquid through vagal‐dependent pathways, sensitive to hexamethonium and yohimbine. Evidence for the participation of the peripheral sympathetic nervous system was not found.