Adrenergic receptors and gastric secretion in dogs. Is a "tonic balance" relationship between vagal and beta 2-adrenergic activity a possibility?
The relative influence of adrenergic receptors on gastric acid secretion in the dog stomach with different vagal activity or "tone" is almost unknown. beta-adrenoceptors seem to be most important for the direct effect of adrenergic stimulation on acid secretion. In this study the effects of vagotomy and beta 2-adrenoceptor activity were studied in conscious gastric fistula dogs. Pentagastrin stimulated acid output was increased slightly in non-vagotomized dogs and to its prevagotomy level in vagotomized dogs after propranolol infusion. Practolol showed no such effect. Histamine stimulated acid secretion was not influenced significantly by beta-blockade. Similar dose-response curves were found for non-vagotomized dogs with high beta 2-adrenergic tone and dogs with low vagal tone (vagotomy) after pentagastrin and histamine stimulated acid secretion. This study indicates that a counterbalance between beta 2-adrenergic and cholinergic vagal tone exists. A "tonic balance theory" is suggested and is probably involved in the resulting acid secretion after vagotomy.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D005744:Gastric Acid / Q000378:metabolism*; D010418:Pentagastrin / Q000494:pharmacology; D011217:Practolol / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013268:Stimulation, Chemical; D014630:Vagus Nerve / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D010418:Pentagastrin; D011217:Practolol