Role of potassium channels in regulation of brain arteriolar tone: comparison of cerebrum versus brain stem

Christopher Graeme Sobey, Frank M Faraci

Research output: Contribution to journalLetterOther

Abstract

Background and Purpose:Potassium channels are important regulators of resting tone in large cerebral arteries, but their activity and distribution may vary according to vessel location and species studied. In the cerebral microcirculation in vivo, however, these channels appear to be silent at rest. Our goal was to determine the activity of potassium channels of brain arterioles from 2 origins under basal conditions in vitro. Methods: Penetrating cerebral (40.9?2.2 ?m control diameter) and brain stem (36.2?1.2 ?m) arterioles of rats were prepared from middle cerebral and basilar arteries, respectively. The internal diameter of cannulated and pressurized vessel was monitored with the inverted microscope before and after administration of potassium channel inhibitors. In addition, we studied the effect of nitric oxide synthase inhibition on potassium channel activity. Results: Cerebral and brain stem arterioles were significantly constricted by 4-aminopyridine and low concentration of BaCl2 but not by glibenclamide. The addition of N-nitro-L-arginine to 4-aminopyridine further decreased diameters of both arterioles. Tetraethylammonium ion caused a significant constriction of brain stem but not cerebral arteriole. The brain stem arteriole was further constricted by additional N-nitro-L-arginine. Conclusions: Voltage-dependent and inward-rectifier, but not ATP-sensitive, potassium channels are active under basal conditions of rat cerebral and brain stem arterioles. There is a regional difference in the activity of calcium-activated potassium channels, which, at rest, are open in brain stem but silent in cerebral arterioles. In addition, basal endogenous nitric oxide may not contribute to the activation of voltage-dependent and calcium-activated potassium channels.
Original languageEnglish
Pages (from-to)224 - 224
Number of pages1
JournalStroke
Volume32
Issue number1
Publication statusPublished - 2001

Cite this

@article{3e274945cb504a24970d3a7d21e70954,
title = "Role of potassium channels in regulation of brain arteriolar tone: comparison of cerebrum versus brain stem",
abstract = "Background and Purpose:Potassium channels are important regulators of resting tone in large cerebral arteries, but their activity and distribution may vary according to vessel location and species studied. In the cerebral microcirculation in vivo, however, these channels appear to be silent at rest. Our goal was to determine the activity of potassium channels of brain arterioles from 2 origins under basal conditions in vitro. Methods: Penetrating cerebral (40.9?2.2 ?m control diameter) and brain stem (36.2?1.2 ?m) arterioles of rats were prepared from middle cerebral and basilar arteries, respectively. The internal diameter of cannulated and pressurized vessel was monitored with the inverted microscope before and after administration of potassium channel inhibitors. In addition, we studied the effect of nitric oxide synthase inhibition on potassium channel activity. Results: Cerebral and brain stem arterioles were significantly constricted by 4-aminopyridine and low concentration of BaCl2 but not by glibenclamide. The addition of N-nitro-L-arginine to 4-aminopyridine further decreased diameters of both arterioles. Tetraethylammonium ion caused a significant constriction of brain stem but not cerebral arteriole. The brain stem arteriole was further constricted by additional N-nitro-L-arginine. Conclusions: Voltage-dependent and inward-rectifier, but not ATP-sensitive, potassium channels are active under basal conditions of rat cerebral and brain stem arterioles. There is a regional difference in the activity of calcium-activated potassium channels, which, at rest, are open in brain stem but silent in cerebral arterioles. In addition, basal endogenous nitric oxide may not contribute to the activation of voltage-dependent and calcium-activated potassium channels.",
author = "Sobey, {Christopher Graeme} and Faraci, {Frank M}",
year = "2001",
language = "English",
volume = "32",
pages = "224 -- 224",
journal = "Stroke",
issn = "0039-2499",
publisher = "American Heart Association",
number = "1",

}

Role of potassium channels in regulation of brain arteriolar tone: comparison of cerebrum versus brain stem. / Sobey, Christopher Graeme; Faraci, Frank M.

In: Stroke, Vol. 32, No. 1, 2001, p. 224 - 224.

Research output: Contribution to journalLetterOther

TY - JOUR

T1 - Role of potassium channels in regulation of brain arteriolar tone: comparison of cerebrum versus brain stem

AU - Sobey, Christopher Graeme

AU - Faraci, Frank M

PY - 2001

Y1 - 2001

N2 - Background and Purpose:Potassium channels are important regulators of resting tone in large cerebral arteries, but their activity and distribution may vary according to vessel location and species studied. In the cerebral microcirculation in vivo, however, these channels appear to be silent at rest. Our goal was to determine the activity of potassium channels of brain arterioles from 2 origins under basal conditions in vitro. Methods: Penetrating cerebral (40.9?2.2 ?m control diameter) and brain stem (36.2?1.2 ?m) arterioles of rats were prepared from middle cerebral and basilar arteries, respectively. The internal diameter of cannulated and pressurized vessel was monitored with the inverted microscope before and after administration of potassium channel inhibitors. In addition, we studied the effect of nitric oxide synthase inhibition on potassium channel activity. Results: Cerebral and brain stem arterioles were significantly constricted by 4-aminopyridine and low concentration of BaCl2 but not by glibenclamide. The addition of N-nitro-L-arginine to 4-aminopyridine further decreased diameters of both arterioles. Tetraethylammonium ion caused a significant constriction of brain stem but not cerebral arteriole. The brain stem arteriole was further constricted by additional N-nitro-L-arginine. Conclusions: Voltage-dependent and inward-rectifier, but not ATP-sensitive, potassium channels are active under basal conditions of rat cerebral and brain stem arterioles. There is a regional difference in the activity of calcium-activated potassium channels, which, at rest, are open in brain stem but silent in cerebral arterioles. In addition, basal endogenous nitric oxide may not contribute to the activation of voltage-dependent and calcium-activated potassium channels.

AB - Background and Purpose:Potassium channels are important regulators of resting tone in large cerebral arteries, but their activity and distribution may vary according to vessel location and species studied. In the cerebral microcirculation in vivo, however, these channels appear to be silent at rest. Our goal was to determine the activity of potassium channels of brain arterioles from 2 origins under basal conditions in vitro. Methods: Penetrating cerebral (40.9?2.2 ?m control diameter) and brain stem (36.2?1.2 ?m) arterioles of rats were prepared from middle cerebral and basilar arteries, respectively. The internal diameter of cannulated and pressurized vessel was monitored with the inverted microscope before and after administration of potassium channel inhibitors. In addition, we studied the effect of nitric oxide synthase inhibition on potassium channel activity. Results: Cerebral and brain stem arterioles were significantly constricted by 4-aminopyridine and low concentration of BaCl2 but not by glibenclamide. The addition of N-nitro-L-arginine to 4-aminopyridine further decreased diameters of both arterioles. Tetraethylammonium ion caused a significant constriction of brain stem but not cerebral arteriole. The brain stem arteriole was further constricted by additional N-nitro-L-arginine. Conclusions: Voltage-dependent and inward-rectifier, but not ATP-sensitive, potassium channels are active under basal conditions of rat cerebral and brain stem arterioles. There is a regional difference in the activity of calcium-activated potassium channels, which, at rest, are open in brain stem but silent in cerebral arterioles. In addition, basal endogenous nitric oxide may not contribute to the activation of voltage-dependent and calcium-activated potassium channels.

M3 - Letter

VL - 32

SP - 224

EP - 224

JO - Stroke

JF - Stroke

SN - 0039-2499

IS - 1

ER -