Caffeine and the control of cerebral hemodynamics.
While the influence of caffeine on the regulation of brain perfusion has been the subject of multiple publications, the mechanisms involved in that regulation remain unclear. To some extent, that uncertainty is a function of a complex interplay of processes arising from multiple targets of caffeine located on a variety of different cells, many of which have influence, either directly or indirectly, on cerebral vascular smooth muscle tone. Adding to that complexity are the target-specific functional changes that may occur when comparing acute and chronic caffeine exposure. In the present review, we discuss some of the mechanisms behind caffeine influences on cerebrovascular function. The major effects of caffeine on the cerebral circulation can largely be ascribed to its inhibitory effects on adenosine receptors. Herein, we focus mostly on the A1, A2A, and A2B subtypes located in cells comprising the neurovascular unit (neurons, astrocytes, vascular smooth muscle); their roles in the coupling of increased neuronal (synaptic) activity to vasodilation; how caffeine, through blockade of these receptors, may interfere with the "neurovascular coupling" process; and receptor-linked changes that may occur in cerebrovascular regulation when comparing acute to chronic caffeine intake.
Pelligrino
Dale A
DA
Neuroanesthesia Research Laboratory, University of Illinois at Chicago, Chicago, IL 60612, USA. dpell@uic.edu
Xu
Hao-Liang
HL
Vetri
Francesco
F
D000818:Animals; D001808:Blood Vessels / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008954:Models, Biological; D018047:Receptors, Purinergic P1 / Q000378:metabolism
D000697:Central Nervous System Stimulants; D018047:Receptors, Purinergic P1; D002110:Caffeine