Received June 13, 2006
Revised July 13, 2006
Accepted after revision July 21, 2006
GI & Epithelial Physiology [230]
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Pentagastrin-induced nitric oxide-dependent protein secretion from the parotid gland of the anaesthetized rat
Hülya Çevik Aras 1
J. Ekström 1*
1 Department of Pharmacology, Institute of Neuroscience and Physiology
* To whom correspondence should be addressed. E-mail: jorgen.ekstrom{at}pharm.gu.se.
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Abstract |
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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 in the rat, as revealed by increased protein concentration in a subsequent wash-out flow of saliva 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-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 (as compared to a pre-infusion methacholine response) were reduced to 68 % and 74 %, respectively, in thepresence of N-PLA, and to 70 % and 63 %, respectively, in the presence of LNAME. Thus, NO generation due to the activity of the neuronal type NO-synthase, most likely of parenchymal origin, plays an important role in the pentagastrin-induced protein and amylase secretion of the rat parotid gland.
Key Words:
Gastrin, Nitric oxide, Salivary gland
