Astrocytes are a key conduit for upstream signaling of vasodilation during cerebral cortical neuronal activation in vivo.
Astrocytes play an important role in the coupling between neuronal activity and brain blood flow via their capacity to "sense" neuronal activity and transmit that information to parenchymal arterioles. Here we show another role for astrocytes in neurovascular coupling: the ability to act as a signaling conduit for the vitally important process of upstream vasodilation (represented by pial arterioles) during both excessive (seizure) and physiological (sciatic nerve stimulation) increases in cerebral cortical neuronal activity. The predominance of an astrocytic rather than a vascular route was indicated by data showing that pial arteriolar-dilating responses to neuronal activation were completely blocked following selective disruption of the superficial glia limitans, whereas interference with interendothelial signaling was without effect. Results also revealed contributions from connexin 43, implying a role for gap junctions and/or hemichannels in the signaling process and that signaling from the glia limitans to pial arterioles may involve a diffusible mediator.
Xu
Hao-Liang
HL
Neuroanesthesia Research Laboratory, University of Illinois at Chicago 60612, USA.
Mao
Lizhen
L
Ye
Shuhua
S
Paisansathan
Chanannait
C
Vetri
Francesco
F
Pelligrino
Dale A
DA
D015074:2-Aminoadipic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001160:Arterioles / Q000502:physiology; D001253:Astrocytes / Q000502:physiology*; D001640:Bicuculline / Q000494:pharmacology; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology*; D017630:Connexins / Q000378:metabolism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D017629:Gap Junctions / Q000502:physiology; D009457:Neuroglia / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D026423:S-Nitroso-N-Acetylpenicillamine / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*
D017630:Connexins; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D026941:Sodium Channel Blockers; D015074:2-Aminoadipic Acid; D013779:Tetrodotoxin; D026423:S-Nitroso-N-Acetylpenicillamine; D000109:Acetylcholine; D001640:Bicuculline