The cyclic AMP level during an increased blood flow in cat cerebral cortex.

The experiments were carried out on cats anesthetized with chloralose, curarized and artificially ventilated. The local cortical CBF was recorded by the thermoclearance technique. The cAMP level in the grey matter of the cerebral cortex and the arterial blood pressure, as well as the arterial blood gas content were measured. Increased concentration of CO2 in the inspired mixture (paCO2 = 79.8 +/- 8.5 mm Hg) caused an enhancement of CBF, without inducing changes in the cAMP level (1.71 +/- 0.07 nmoles/g wet weight). Increasing the PaCO2 up to 184.42 +/- 12.3 mm Hg produced neither a further increase of CBF, nor a rise of cAMP level. Adrenaline injected into the cerebral ventricles led to an increase of cAMP up to 4.42 +/- 0.7 nmoles/g without changing CBF. Saline in the same volume increased cAMP level to a smaller degree (2.71 +/- 0.26 nmoles/g). No changes in CBF were registered. Dibutyryl cAMP, cAMP and adenosine injected into a. lingualis did not significantly change the CBF.