PHOTOCHEMICAL PROPERTIES OF NEW PHOTOLABILE CAMP DERIVATIVES IN A PHYSIOLOGICAL SALINE SOLUTION

Three new photolabile esters of cAMP (2-anthraquinonyl)methyl (la), (7-methoxycoumarinyl)methyl (2a), and 2-naphthylmethyl (3a), have been developed. The stability and photochemical properties of these derivatives were compared to the previously reported ones in a physiological saline solution (1% DMSO in Ringer's solution, pH 7.4). We found that 2a had satisfactory stability (t(1/2) > 1000 h) in the dark and was photolyzed to release the parent cAMP on 340 nm irradiation (phi(app) = 0.10, epsilon(340) = 6730) more efficiently than previously reported caged cAMPs. A biological test using the melanophores of the medaka (Oryzias latipes) revealed that 2a penetrated into the melanophores, inactive before irradiation and activated to release cAMP upon irradiation. We have developed a new caged cAMP which can be used in the investigation of biological responses regulated by intracellular cAMP concentrations using living cells.