Effect of intravenous adenosine-tri-phosphate (ATP) on cerebral blood flow by bolus 15O-labeled water PET study on human volunteers

Abstract

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Objectives: Adenosine triphosphate (ATP) is well known as a powerful vasodilator. It is being used for the measurement of coronary flow reserve. There are some conflicting reports of role of adenosine on cerebral vasodilation in human. However, it has not been investigated whether intravenous ATP could cause significant vasodilation of the cerebral arteries causing a change in cerebral blood flow (CBF). This study employing positron emission tomography (PET) investigated the effect of intravenous ATP on human CBF using 15O-labeled water.

Methods: Eight healthy young male volunteers (aged 20 to 25 years) underwent intravenous bolus 15O-labeled water PET scans. Study protocol included baseline, 1 and 3 minutes post-ATP (0.16mg/kg/min) studies. CBF images were calculated from the dynamic PET data and arterial blood curves by autoradiographic method. Multiple regions of interest were placed in each cerebral hemisphere. Statistical parametric mapping (SPM) was utilized in the data analysis.

Results: Cortical CBF values were slightly reduced after ATP. At 1min post-injection, CBF was 55.4 ± 5 ml/100g/min compared to baseline of 55.9 ± 5.6 ml/100g/min. At 3min post-injection, it was 54.9 ± 5.3 ml/100g/min compared to baseline of 56.2 ± 5 ml/100g/min. One-way ANOVA did not show any significant differences. There was slight decrease of PaCO2 after ATP (41.6 vs. 39.6 mmHg), which was also non-significant. SPM analysis revealed no regional differences.

Conclusions: The results indicate that intravenous ATP administration resulted in non-significant change of CBF. This correlates with the reported findings of intravenous adenosine administration. So normal CBF is maintained in response to intravenous ATP.