ISSN:
1573-2568
Schlagwort(e):
rabbit parietal cells
;
[14C]aminopyrine accumulation
;
adenosine
;
adenosine analogs
;
cyclic AMP
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract Adenosine receptors that modulate adenylate cyclase activity have been identified recently in a number of tissues. Adenosine A2 receptor is stimulatory to adenylate cyclase, whereas adenosine A1 receptor is inhibitory to adenylate cyclase. We investigated the effect of adenosine and its analogs on [14C]aminopyrine accumulation by rabbit parietal cells. Rabbit gastric mucosal cells were isolated by enzyme digestion. Parietal cells were enriched by nonlinear percoll gradients. [14C]Aminopyrine accumulation was used as an indicator of acid secretion. The effect of 2-chloroadenosine on histamine-stimulated [14C]aminopyrine accumulation was studied. The effects ofN-ethylcarboxamideadenosine, 2-chloroadenosine, stable analogs of adenosine, and adenosine on [14C]aminopyrine accumulation were assessed. Cyclic AMP content of parietal cells was determined by radioimmunoassay. Histamine and carbachol, known secretagogues, stimulated [14C]aminopyrine accumulation. 2-Chloroadenosine did not suppress histaminestimulated [14C]aminopyrine accumulation. 2-Chloroadenosine,N-ethylcarboxamideadenosine, and adenosine dose dependently increased [14C]aminopyrine accumulation. The order of potency wasN-ethylcarboxamideadenosine 〉 2-chloroadenosine 〉 adenosine. 8-Phenyltheophylline and theophylline, adenosine-receptor antagonists, or cimetidine did not have significant effects on the increase of AP uptake induced by 2-chloroadenosine. Coadministration of dipyridamole, an adenosine uptake inhibitor, augmented the effect of adenosine on [14C]aminopyrine accumulation. 2-Chloroadenosine,N-ethylcarboxamideadenosine, and adenosine each induced a significant increase in cellular cyclic AMP. We conclude that there may be adenosine A2 receptors on rabbit parietal cells which modulate gastric acid secretion.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01536706
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