Precapillary sphincters maintain perfusion in the cerebral cortex in health and constrict in a migraine model and in cerebral ischaemia
Søren Grubb, Changsi Cai, Bjørn O. Hald, Lila Khennouf, Jonas Fordsmann, Reena Prity Murmu, Aske G. K. Jensen, Stefan Zambach & Martin Lauritzen
Date Received: 5th July 19
Active nerve cells release vasodilators that increase their energy supply by dilating local blood vessels, a mechanism termed neurovascular coupling and the basis of BOLD functional neuroimaging signals. Here, we reveal a unique mechanism for cerebral blood flow control, a precapillary sphincter at the transition between the penetrating arteriole and first order capillary, linking blood flow in capillaries to the arteriolar inflow. The sphincters are encircled by contractile mural cells, which are capable of bidirectional control of the length and width of the enclosed vessel segment. The haemodynamic consequence is that precapillary sphincters can generate the largest changes in the cerebrovascular flow resistance of all brain vessel segments, thereby controlling capillary flow while protecting the capillary bed and brain tissue from adverse pressure fluctuations. Global ischaemia and cortical spreading depolarization constrict sphincters and cause vascular trapping of blood cells. Thus, precapillary sphincters are bottlenecks for brain capillary blood flow.
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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.