THE ROLE OF MAGNESIUM IN THE ENDOTHELIAL DYSFUNCTION...

THE ROLE OF MAGNESIUM IN THE ENDOTHELIAL DYSFUNCTION CAUSED BY GLOBAL ISCHEMIA FOLLOWED BY REPERFUSION: IN VITRO STUDY OF CANINE CORONARY ARTERIES.

Revista Taylor & Francis healthsciences.
 
Autores:

1) Marco A. Volpe – Endothelium Laboratory, Divisison of Experimetal Surgery and Division of Thoracic and Cardiovascular Surgery, Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, USP.

2)João J. Carneiro - Endothelium Laboratory, Divisison of Experimetal Surgery and Division of Thoracic and Cardiovascular Surgery, Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, USP.

3) Luís Alberto Magna – Department of medical Genetics, Faculdade de Ciências Médicas, UNICAMp, SP, Brazil.

4)Fernanda Viaro - Endothelium Laboratory, Divisison of Experimetal Surgery and Division of Thoracic and Cardiovascular Surgery, Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, USP.

5)Eliana Aparecida L. Origuela - Endothelium Laboratory, Divisison of Experimetal Surgery and Division of Thoracic and Cardiovascular Surgery, Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, USP.

6)Paulo R. B. Évora -  Endothelium Laboratory, Divisison of Experimetal Surgery  and Division of Thoracic and Cardiovascular Surgery, Department of Surgery and Anatomy, Faculdade de Medicina de Ribeirão Preto, USP.
 

Objective: To study the role of magnesium in the endothelial dysfunction of canine coronary arteries caused by cardiopulmonary bypass (CPB) global ischemia followed by reperfusion.

Design:
Segments of canine coronary arteries were suspended n organ chambers to measure isometric contraction by prostaglandin F2α , and relaxeded by acetylcholine (Ach), sodium fluoride (NaF), calcium ionophore (A23187) and sodium  nitroprusside (SNP) in crescent concentrations. The investigation protocol had groups with six dogs: CONTROL group (without CPB), CPB groups (105 min of CPB group without aortic cross-clamping), ISCH/REP group (45 min of aortic cross-clamping followed by 60 min of reperfusion). The coronary relaxations were evaluated with (phase I), without (phase II) and restored magnesium (phase III) to the organ bath.
 
Results – The presence of magnesium in the organ bath was associated with the greater relaxation in response to agonists of the nitric oxide production. The removal of magnesium from the organ bath was associated with the reduction in the Intensity of relaxation. The magnesium restoration to the organ bath was associated with the additional reduction in the intensity of relaxation with the exception of NaF that allowed reacquisition of the relaxation observed in the presence of magnesium.
 
Conclusion – This in vitro study demonstrates that magnesium ion favorably influences the nitric oxide production by the coronary endothelium, attenuating the endothelial dysfunction caused by global ischemia followed by reperfusion.