Further evidence for the involvement of cAMP in central blood pressure regulation.

In order to test the hypothesis that the activity of cardiovascular centres is determined by their content of cAMP a number of drugs which influence the activity of either phosphodiestase or adenylcyclase were injected in doses of 100-1000 mug/kg into the lateral cerebral ventricle of cats. The effects on blood pressure and heart rate were studied. The phosphodiesterase inhibitors papaverine, carbocromene, theophylline and caffeine caused hypertension and tachycardia which increased with the dose while the phosphodiesterase activator imidazole exerted opposite effects. Sodium fluoride which activates adenylcyclase increased blood pressure and heart rate substantially. The results confirm the above-mentioned hypothesis.