Abstract
The pH of brain extracellular fluid (EGF) close to the cerebral arterioles is a well-established determinant of cerebral blood flow (GBF). Recently the role of other vasoactive ions has been questioned. Kuschinsky et al. (8) and Heuser et al. (7) found in cats that an increase in perivascular K+ to approximately 10 mM produced vasodilatation, and a reduction in K+ below normal, vasoconstriction. Cameron and Segal (4), using the same technique, found K+ to have variable effects depending on local pH. The micropipette technique used involves exposure of the cortex and injections close to the pial vessels. The disadvantages are that the local PCO 2 is unknown and difficult to control, and blood flow is not measured. Furthermore, the vessels investigated are not the site of main resistance (12).
Published Version
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