A Radioisotopic Method for Measuring the Formation of Adenosine 3′,5′‐cyclic Monophosphate in Incubated Slices of Brain

Abstract— A simple and sensitive method for measuring the effect of neurohormones and other chemical agents on the formation of adenosine 3′,5′‐cyclic monophosphate (cyclic 3′,5′‐AMP) in incubated slices of brain was developed. The principle of the method depends on pulse‐labelling of adenosine‐5′‐triphosphate in slices of brain with 8‐ 14 Cadenine, followed by incubation in a medium containing the test substance, separation by thin‐layer chromatography of the cyclic nucleotide formed in the slices, and radioassay. The purity of the cyclic nucleotide was confirmed by chromatography in a variety of systems and by hydrolysis with a specific, bovine‐heart phosphodiesterase. The method was used to study the effect of histamine, norepinephrine, and adenosine on the accumulation of adenosine 3′,5′‐cyclic monophosphate in incubated slices of brain.