Effect of caffeine on theophyliine on cerebral blood flow response to brain activation: In vitro and in vivo studies

Despite its wide consumption and well-documented psychoactive effects, little is known regarding the effects of caffeine, an adenosine receptor antagonist, on neurovascular coupling. In the present study, we evaluated the effects of caffeine on intracerebral arterioles in vitro and on the pial circulation in vivo during cortical activation induced by contralateral sciatic nerve stimulation (SNS). In our in vitro studies, we utilized isolated intracerebral arterioles to determine the effects of caffeine (10 or 50uM) on vasodilatation induced by extraluminal application of adenosine. Adenosine caused dose-dependent dilations. Pretreatment with caffeine alone, at either of the concentrations tested, had no effect on resting diameter. The higher concentration (50uM) of caffeine resulted in significant attenuation of adenosine-induced vasodilatation (p