Endothelium-dependent influence of small changes in extracellular magnesium concentration on the tone of feline middle cerebral arteries

Csaba Szabo, Mária Faragó, Eörs Dóra, Ildikó Horváth, Arisztid G B Kovách

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The aim of this study was to investigate the effect of small alterations in the extracellular magnesium concentration on the tone of feline middle cerebral arteries and to examine the role of the endothelium in these responses. We measured the isometric tension of isolated arterial rings placed between two stainless steel wires in a tissue chamber containing Krebs-Henseleit solution aerated with a gas mixture containing 95% O2 and 5% CO2 at 37°C. After precontraction with noradrenaline, a decrease of the extracellular magnesium concentration from 1.2 mM to 1.0 and 0.8 mM resulted in sustained relaxations, whereas elevation of the extracellular magnesium concentration from 0.8 mM to 1.2 mM caused an increase in vascular tone when the endothelium was intact. The magnesium deficiency-related dilations were absent in endothelium-denuded vessels and were inhibited by 5×10-6 M oxyhemoglobin and 10-5 M methylene blue, suggesting the involvement of an endothelium-derived relaxing factor in this vascular response. However, 5×10-7 M nifedipine or 3×10-5 M dichlorobenzamil did not affect the magnesium deficiency-related relaxations. Therefore, nifedipine-sensitive calcium channels or the sodium/calcium antiport system are not involved in this vascular action of magnesium. We conclude that small alterations in the extracellular magnesium concentration, possibly within the physiological range, are able to modify the basal formation and release of endotheliumderived relaxing factor and thus alter arterial smooth muscle tone in this vascular bed. This endothelium- and magnesium-dependent system appears to be more sensitive than the direct smooth muscle actions of magnesium and might exert a protective effect against magnesium deficiency-induced direct cerebrovascular contraction.

Original languageEnglish (US)
Pages (from-to)785-789
Number of pages5
JournalStroke
Volume22
Issue number6
StatePublished - Jun 1991
Externally publishedYes

Fingerprint

Felidae
Middle Cerebral Artery
Magnesium
Endothelium
Magnesium Deficiency
Blood Vessels
Nifedipine
Smooth Muscle
Endothelium-Dependent Relaxing Factors
Oxyhemoglobins
Methylene Blue
Stainless Steel
Ion Transport
Calcium Channels
Dilatation
Norepinephrine
Arterial Pressure
Gases
Sodium
Calcium

Keywords

  • Cats
  • Endothelium
  • Magnesium
  • Muscle, smooth

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Neuroscience(all)

Cite this

Endothelium-dependent influence of small changes in extracellular magnesium concentration on the tone of feline middle cerebral arteries. / Szabo, Csaba; Faragó, Mária; Dóra, Eörs; Horváth, Ildikó; Kovách, Arisztid G B.

In: Stroke, Vol. 22, No. 6, 06.1991, p. 785-789.

Research output: Contribution to journalArticle

Szabo, Csaba ; Faragó, Mária ; Dóra, Eörs ; Horváth, Ildikó ; Kovách, Arisztid G B. / Endothelium-dependent influence of small changes in extracellular magnesium concentration on the tone of feline middle cerebral arteries. In: Stroke. 1991 ; Vol. 22, No. 6. pp. 785-789.
@article{ad3926f164df496cbea3c3fe3e9a807d,
title = "Endothelium-dependent influence of small changes in extracellular magnesium concentration on the tone of feline middle cerebral arteries",
abstract = "The aim of this study was to investigate the effect of small alterations in the extracellular magnesium concentration on the tone of feline middle cerebral arteries and to examine the role of the endothelium in these responses. We measured the isometric tension of isolated arterial rings placed between two stainless steel wires in a tissue chamber containing Krebs-Henseleit solution aerated with a gas mixture containing 95{\%} O2 and 5{\%} CO2 at 37°C. After precontraction with noradrenaline, a decrease of the extracellular magnesium concentration from 1.2 mM to 1.0 and 0.8 mM resulted in sustained relaxations, whereas elevation of the extracellular magnesium concentration from 0.8 mM to 1.2 mM caused an increase in vascular tone when the endothelium was intact. The magnesium deficiency-related dilations were absent in endothelium-denuded vessels and were inhibited by 5×10-6 M oxyhemoglobin and 10-5 M methylene blue, suggesting the involvement of an endothelium-derived relaxing factor in this vascular response. However, 5×10-7 M nifedipine or 3×10-5 M dichlorobenzamil did not affect the magnesium deficiency-related relaxations. Therefore, nifedipine-sensitive calcium channels or the sodium/calcium antiport system are not involved in this vascular action of magnesium. We conclude that small alterations in the extracellular magnesium concentration, possibly within the physiological range, are able to modify the basal formation and release of endotheliumderived relaxing factor and thus alter arterial smooth muscle tone in this vascular bed. This endothelium- and magnesium-dependent system appears to be more sensitive than the direct smooth muscle actions of magnesium and might exert a protective effect against magnesium deficiency-induced direct cerebrovascular contraction.",
keywords = "Cats, Endothelium, Magnesium, Muscle, smooth",
author = "Csaba Szabo and M{\'a}ria Farag{\'o} and E{\"o}rs D{\'o}ra and Ildik{\'o} Horv{\'a}th and Kov{\'a}ch, {Arisztid G B}",
year = "1991",
month = "6",
language = "English (US)",
volume = "22",
pages = "785--789",
journal = "Stroke",
issn = "0039-2499",
publisher = "Lippincott Williams and Wilkins",
number = "6",

}

TY - JOUR

T1 - Endothelium-dependent influence of small changes in extracellular magnesium concentration on the tone of feline middle cerebral arteries

AU - Szabo, Csaba

AU - Faragó, Mária

AU - Dóra, Eörs

AU - Horváth, Ildikó

AU - Kovách, Arisztid G B

PY - 1991/6

Y1 - 1991/6

N2 - The aim of this study was to investigate the effect of small alterations in the extracellular magnesium concentration on the tone of feline middle cerebral arteries and to examine the role of the endothelium in these responses. We measured the isometric tension of isolated arterial rings placed between two stainless steel wires in a tissue chamber containing Krebs-Henseleit solution aerated with a gas mixture containing 95% O2 and 5% CO2 at 37°C. After precontraction with noradrenaline, a decrease of the extracellular magnesium concentration from 1.2 mM to 1.0 and 0.8 mM resulted in sustained relaxations, whereas elevation of the extracellular magnesium concentration from 0.8 mM to 1.2 mM caused an increase in vascular tone when the endothelium was intact. The magnesium deficiency-related dilations were absent in endothelium-denuded vessels and were inhibited by 5×10-6 M oxyhemoglobin and 10-5 M methylene blue, suggesting the involvement of an endothelium-derived relaxing factor in this vascular response. However, 5×10-7 M nifedipine or 3×10-5 M dichlorobenzamil did not affect the magnesium deficiency-related relaxations. Therefore, nifedipine-sensitive calcium channels or the sodium/calcium antiport system are not involved in this vascular action of magnesium. We conclude that small alterations in the extracellular magnesium concentration, possibly within the physiological range, are able to modify the basal formation and release of endotheliumderived relaxing factor and thus alter arterial smooth muscle tone in this vascular bed. This endothelium- and magnesium-dependent system appears to be more sensitive than the direct smooth muscle actions of magnesium and might exert a protective effect against magnesium deficiency-induced direct cerebrovascular contraction.

AB - The aim of this study was to investigate the effect of small alterations in the extracellular magnesium concentration on the tone of feline middle cerebral arteries and to examine the role of the endothelium in these responses. We measured the isometric tension of isolated arterial rings placed between two stainless steel wires in a tissue chamber containing Krebs-Henseleit solution aerated with a gas mixture containing 95% O2 and 5% CO2 at 37°C. After precontraction with noradrenaline, a decrease of the extracellular magnesium concentration from 1.2 mM to 1.0 and 0.8 mM resulted in sustained relaxations, whereas elevation of the extracellular magnesium concentration from 0.8 mM to 1.2 mM caused an increase in vascular tone when the endothelium was intact. The magnesium deficiency-related dilations were absent in endothelium-denuded vessels and were inhibited by 5×10-6 M oxyhemoglobin and 10-5 M methylene blue, suggesting the involvement of an endothelium-derived relaxing factor in this vascular response. However, 5×10-7 M nifedipine or 3×10-5 M dichlorobenzamil did not affect the magnesium deficiency-related relaxations. Therefore, nifedipine-sensitive calcium channels or the sodium/calcium antiport system are not involved in this vascular action of magnesium. We conclude that small alterations in the extracellular magnesium concentration, possibly within the physiological range, are able to modify the basal formation and release of endotheliumderived relaxing factor and thus alter arterial smooth muscle tone in this vascular bed. This endothelium- and magnesium-dependent system appears to be more sensitive than the direct smooth muscle actions of magnesium and might exert a protective effect against magnesium deficiency-induced direct cerebrovascular contraction.

KW - Cats

KW - Endothelium

KW - Magnesium

KW - Muscle, smooth

UR - http://www.scopus.com/inward/record.url?scp=0026094854&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026094854&partnerID=8YFLogxK

M3 - Article

VL - 22

SP - 785

EP - 789

JO - Stroke

JF - Stroke

SN - 0039-2499

IS - 6

ER -