TY - JOUR
T1 - Role of ATP-sensitive potassium channels in brain stem circulation during hypotension
AU - Toyoda, Kazunori
AU - Fujii, Kenichiro
AU - Ibayashi, Setsuro
AU - Kitazono, Takanari
AU - Nagao, Tetsuhiko
AU - Fujishima, Masatoshi
PY - 1997/1/1
Y1 - 1997/1/1
N2 - The basilar artery and its branch arterioles dilate actively in response to a marked decrease in blood pressure and maintain cerebral blood flow (CBF) to the brain stem. We tested the hypothesis that ATP-sensitive potassium (K(ATP)) channels play a role in the autoregulatory responses of the brain stem circulation in vivo. In anesthetized Sprague-Dawley rats, local CBF to the brain stem was determined with laser-Doppler flowmetry, and diameters of the basilar artery and branch arterioles were measured through a cranial window during stepwise hemorrhagic hypotension. During topical application of 10+6 and 10+5 mol/l of glibenclamide, a selective K(ATP)-channel blocker, the lower limit of CBF autoregulation shifted upward to 60-75 from 30-45 mmHg in the vehicle group. Glibenclamide significantly impaired the dilator response of small arterioles (baseline diameter 45 ± 2 μm) throughout hypotension (P < 0.03) but did not impair the dilatation of the basilar artery (247 ± 3 Mm) or large arterioles (99 ± 4 Mm). Thus K(ATP) channels appear to play an important role in the regulation of CBF to the the brain stem during hypotension by mediating the compensatory dilatation of small arterioles. In contrast, these channels may not be a major regulator of the vascular tone of larger arteries during hypotension.
AB - The basilar artery and its branch arterioles dilate actively in response to a marked decrease in blood pressure and maintain cerebral blood flow (CBF) to the brain stem. We tested the hypothesis that ATP-sensitive potassium (K(ATP)) channels play a role in the autoregulatory responses of the brain stem circulation in vivo. In anesthetized Sprague-Dawley rats, local CBF to the brain stem was determined with laser-Doppler flowmetry, and diameters of the basilar artery and branch arterioles were measured through a cranial window during stepwise hemorrhagic hypotension. During topical application of 10+6 and 10+5 mol/l of glibenclamide, a selective K(ATP)-channel blocker, the lower limit of CBF autoregulation shifted upward to 60-75 from 30-45 mmHg in the vehicle group. Glibenclamide significantly impaired the dilator response of small arterioles (baseline diameter 45 ± 2 μm) throughout hypotension (P < 0.03) but did not impair the dilatation of the basilar artery (247 ± 3 Mm) or large arterioles (99 ± 4 Mm). Thus K(ATP) channels appear to play an important role in the regulation of CBF to the the brain stem during hypotension by mediating the compensatory dilatation of small arterioles. In contrast, these channels may not be a major regulator of the vascular tone of larger arteries during hypotension.
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U2 - 10.1152/ajpheart.1997.273.3.h1342
DO - 10.1152/ajpheart.1997.273.3.h1342
M3 - Article
C2 - 9321824
AN - SCOPUS:33751304218
VL - 273
SP - H1342-H1346
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 3 42-3
ER -