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The effect of adrenergic, cholinergic and peptidergic salivary stimulants on gastric mucosal integrity in the rat.
Author(s) -
Soper B D,
Tepperman B L
Publication year - 1986
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1986.sp016288
Subject(s) - cholinergic , adrenergic , parasympathomimetics , endocrinology , acetylcholine , medicine , pharmacology , chemistry , neuroscience , biology , muscarinic acetylcholine receptor , receptor
Sialoadenectomized and sham‐operated rats were given salivary secretory stimulants 30 min prior to intragastric instillation of a bile salt solution (5 mM‐sodium taurocholate in 100 mM‐HCl). Administration of the alpha‐agonist phenylephrine (0.15‐15 mg/kg) resulted in a dose‐dependent reduction in the loss of H+ and the intraluminal appearance of Na+ and K+ associated with bile‐salt‐induced damage to the stomach in the sham‐sialoadenectomized rat. The effect was not apparent if the salivary glands had been previously excised. Adrenaline (0.8‐4.0 mg/kg) and noradrenaline (0.8‐4.0 mg/kg) were less effective in reducing the degree of mucosal damage in sham‐sialoadenectomized rats and were not effective in sialoadenectomized rats. Administration of secretory stimulant doses of isoprenaline (5 mg/kg), pilocarpine (2 mg/kg) and substance P (25 mg/kg) either had no significant effect or exacerbated the net transmucosal fluxes of H+, Na+ and K+ associated with bile salt damage to the gastric mucosa. The protective action of phenylephrine in sham‐sialoadenectomized rats was reversed by prior treatment with the alpha‐antagonist, phentolamine (2 mg/kg). The effect of phentolamine was dose dependent. Vagotomy abolished the protective influence of phenylephrine in sham‐sialoadenectomized rats but did not influence the response to other salivary secretory stimulants consistently. These data suggest that stimulation of alpha‐adrenergic receptors in rat salivary tissue is associated with an amelioration of the increase in gastric mucosal permeability to H+, Na+ and K+ in response to an intraluminal bile salt solution. The apparent protective influence of alpha‐adrenergic receptor activation in sham‐sialoadenectomized rats is mediated in part by the vagus nerve.