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Pentagastrin‐induced nitric oxide‐dependent protein secretion from the parotid gland of the anaesthetized rat
Author(s) -
Çevik Aras Hülya,
Ekström J.
Publication year - 2006
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2006.034710
Subject(s) - pentagastrin , endocrinology , medicine , methacholine , amylase , nitric oxide synthase , secretion , chemistry , nitric oxide , saliva , bolus (digestion) , biology , enzyme , biochemistry , gastric acid , respiratory disease , lung
Infusion of pentagastrin (20 μg kg −1 h −1 , i.v. ) for 10 min evokes protein output but no overt fluid secretion from the parotid gland of the rat, as revealed by increased protein concentration in a subsequent wash‐out flow of saliva in response to a bolus injection of methacholine (5 μg kg −1 , i.v .) 10 min later. Using this experimental set‐up, the contribution of nitric oxide (NO) generation to the protein and amylase response evoked by pentagastrin was investigated. Neither the neuronal type NO synthase inhibitor N ω ‐propyl‐ l ‐arginine ( N ‐PLA; 30 mg kg −1 , i.v .) nor the non‐selective NO synthase inhibitor l ‐NAME (30 mg kg −1 , i.v .) as such affected the methacholine‐evoked volume response or the outputs of protein and amylase. However, when preceeded by the pentagastrin infusion, the expected increases in concentrations of protein (145%) and amylase activity (127%) of the methacholine‐evoked response (compared to a pre‐infusion methacholine response) were reduced to 68 and 74%, respectively, in the presence of N ‐PLA, and to 70 and 63%, respectively, in the presence of l ‐NAME. Thus, NO generation resulting from the activity of the neuronal type NO synthase, most probably of parenchymal origin, plays an important role in the pentagastrin‐induced protein and amylase secretion of the rat parotid gland.