Figure 5. Effect of ethanol exposure on cellular cAMP level and adenosine analog antagonizes ethanol suppression of adenosine-induced chloride secretion.

A) Calu-3 epithelia, exposed to 0 and 100 mM of ethanol for 24 hours, were apically stimulated with 100 µM of adenosine for 10 min. Cells were lysed and cAMP levels were estimated by immunoassay. Ethanol pre-exposure significantly decreased the adenosine-induced cellular cAMP level to ∼64% of the no ethanol control (p<0.05, n = 5). B) In Calu-3 epithelia, ethanol pre-exposure decreased the adenosine-stimulated I_SC. Such an inhibitory effect of ethanol on adenosine-induced I_SC was antagonized by Sp-cAMPS, a phoshodiesterase-resistant cAMP analog (p<0.05, n = 6).