CWRU scientists reveal how magnesium works on ion channels important for regulating blood pressure

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CWRU scientists reveal how magnesium works on ion channels important for

regulating blood pressure

CLEVELAND-- Researchers at Case Western Reserve University report in the

August 22 issue of Nature how magnesium activates microscopic ion channels

in the membrane of a cell. These particular ion channels are important in

controlling blood pressure. Scientists, the researchers say, can use this

new finding in the quest to understand how magnesium helps to decrease blood

pressure and also treat heart failure and stroke.

Calcium activated potassium channels are important microscopic pathways in

the cell membrane that relax the smooth muscle in a blood vessel, according

to the researchers. They also modify electrical impulses, which travel in

nerve cells throughout the brain.

" Research of this kind may help to understand why some therapies such as

magnesium supplements are important in the prevention and management of

hypertension or heart failure, " said Jianmin Cui, the lead researcher and

assistant professor in the department of biomedical engineering at CWRU.

" Along with some other groups, we have discovered that when magnesium is

applied to calcium-activated potassium channels, these channels will open.

We know from literature that the opening of these channels can reduce blood

pressure. "

The Nature article ( " Mechanism of magnesium activation of calcium activated

potassium channels " ) was written by Jianmin Cui, the principal researcher,

who was assisted by Jingyi Shi, senior researcher in the department of

biomedical engineering; Gayathri Krishnamoorty and Lei Hu, graduate students

in the department of biomedical engineering; and Neha Chaturvedi and Dina

Harilal, undergraduates students. The team is collaborating with Yanwu Yang

and Jun Qin, structural biologists at the Cleveland Clinic Foundation. The

research is supported by a $1 million grant from the National Institutes of

Health, Heart Lung and Blood Institute.

" The completion of stage one of the project is due to the combination of

state-of-the-art bioelectric facilities and advanced structural biology

results, " Cui said. " The collaboration between the department of biomedical

engineering and The Cleveland Clinic Foundation was key. "

CWRU researchers used cloned ion channel DNA to express the ion channels in

frog eggs. The ion channels are proteins made of various amino acids; the

researchers mutated some of these amino acids and recorded functional change

that resulted from the mutations.

Hypertension, Cui explained, results from the contraction of blood vessels,

which causes an increase in blood pressure. " The diameter of blood vessels

is controlled by smooth muscle cells around them, " he said. " When magnesium

reaches these potassium channels, the channels open causing blood vessels to

dilate and therefore reduce hypertension. "

According to the National Health and Nutrition Examination Survey conducted

between 1988 and 1994 by The National High Blood Pressure Education Program,

an estimated 42.3 million people in the U.S had hypertension. Doctors had

told an additional 7.7 million on two or more occasions that they had

hypertension, which gives a total of 50 million hypertensives.

" Our research is basic science, however, we hope that the results can help

to explain why some treatments would work and provide rationale for

development of new drugs for hypertension, " Cui said.