Elevation of guanosine 3′,5′-monophosphate level by adenosine in cerebellar slices of guinea pig

Effect of adenosine on the level of guanosine 3′,5′-monophosphate in guinea pig cerebellar slices was investigated. Adenosine increased the concentration of guanosine 3′,5′-monophosphate in the slices 3–4-fold. Upon removal of adenosine from the medium, the concentration of guanosine 3′,5′-monophosphate returned to the initial level. AMP, ADP or ATP also increased the guanosine 3′,5′-monophosphate level to the same extent as adenosine, while adenine or other nucleotides were not effective. In the absence of Ca²⁺ in the incubation medium, adenosine did not increase the concentration of guanosine 3′,5′-monophosphate in cerebellar slices although level of adenosine 3′,5′-monophosphate was elevated by adenosine.Anticholinergic agents, adrenergic blocking agents or antihistaminics did not prevent the increase of guanosine 3′,5′-monophosphate by adenosine indicating that the effect of adenosine was not mediated by the release of neurotransmitters.The combination of adenosine with depolarizing agents showed an additive effect on the level of guanosine 3′,5′-monophosphate indicating that adenosine increased the level of guanosine 3′,5′-monophosphate by a different mechanism from the depolarization.