Vasodilatory effect of adenosine triphosphate does not change cerebral blood flow: a PET study with 15O-water

Objective Adenosine triphosphate (ATP) is the parent compound of adenosine and well known as a powerful vasodilator. To investigate the effect of ATP on cerebral blood flow (CBF) and cerebral vessels, O-15-water positron emission tomography (PET) studies were performed to evaluate changes in CBF and blood volume before and after ATP administration. Methods Ten healthy young volunteers underwent O-15-water PET scans under the conditions of baseline, 3 and 1 min after ATP continuous infusion. CBF values in cortical regions of the bilateral middle cerebral arteries and basal ganglia were obtained for each subject. Statistical parametric mapping (SPM) was applied for analysis of regional changes. Physiologic parameters, such as blood gas and blood pressure were also measured. Results Cortical CBF showed no significant change after continuous infusion of ATP compared with the baseline. Dilatation of major vessels induced by ATP was visualized on SPM analysis. Heart rates increased and mean blood pressure decreased during ATP administration while blood gas data showed no changes between the different conditions. Conclusions Intravenous ATP administration caused dilatation of major cerebral vessels but no significant change in CBF under normoventilation and decrease in systemic blood pressure, indicating that this no change in CBF under vasodilatory effect of ATP may be caused by cerebral microvascular autoregulation.