Adenosine A1 receptor activation inhibits histamine release in gastric enterochromaffin-like cells

Adenosine acts as a gastroprotective factor decreasing inflammation and reducing gastric acid secretion. Quantitative RT-PCR was used to determine the expression of the adenosine receptor genes (A1AR, A2AAR, A2BAR and A3AR) and that of the gastrin receptor B gene (CCKBR) in isolated, short-term cultured enterochromaffin-like (ECL) cells. Both the A1AR and the CCKBR genes were expressed at a level higher than the other genes. Also, the effect of 2-chloroadenosine, a stable agonist of A1 and A2A receptors, was explored on ECL cells, with a resulting inhibition of both basal and gastrin-stimulated histamine release. Also, dipropylcyclopentylxanthine (DPCPX), a selective A1 antagonist, prevented the inhibitory effects of 2-chloroadenosine, suggesting the effect of 2-chloroadenosine is mediated by A1 receptors. It is concluded that isolated, short-term cultured ECL cells are a suitable model for studies relating gene expression and function, and that the gastroprotective actions of adenosine are at least partly mediated through A1 receptors.