cAMP as a second messenger in central blood pressure control.

Injections of dibutyryl cyclic adenosine 3',5'-monophosphate in doses of 125, 250 and 500 mug/kg into the lateral cerebral ventricle of anaesthetised cats produced dose dependent increases in blood pressure and heart rate, while doses of 50, 100 and 200 mug/kg imidazole-4-acetic acid, a stimulator of phosphodiesterase, exerted an opposite effect. The results are discussed in the light of the hypothesis that the activity of cardiovascular centres is determined by their concentration of cyclic AMP.