NO action on vessel

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NO action on vessel

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twesting2173
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09/21/06 - 12:47 PM

can someone tell me if i am corret:

NO is produced in the endothelial lining of the vessel, but it diffuses out and binds to it's receptor on smooth muscle, right? so NO produces vasodilation via relaxation of smooth muscle.

please correct if i'm worng.
thanks.

Musuq
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09/21/06 - 02:28 PM

Yup, It's a wonderful system, based on the ability of NO to dilate the blood vessels as needed. When NO molecules are produced in Endothelial Cells, they rapidly diffuse through the cell membrane into the underlying Smooth Muscle cells, inhibiting their contraction and causing them to relax. The resulting dilation of the blood vessel increases blood flow and decreases blood pressure.

Guys, let's also discuss the nbme questions for Physio, I will start checking them tonight.

twesting2173
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09/21/06 - 03:41 PM

oh wow, thanks. tell me whcih Q you want ot talk about.

young_doc
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09/21/06 - 04:21 PM

Don't forget the exact MECHANISM!!

NO activates GC...hence increased cGMP...hence sequestration of Ca and thus relaxation.

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Leopard
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09/21/06 - 04:36 PM

young_doc wrote:
Don't forget the exact MECHANISM!!

NO activates GC...hence increased cGMP...hence sequestration of Ca and thus relaxation.

CGMP produced by activation of GC (stimulated by NO) does not relax smooth muscles by Ca-sequestration but it is in fact activation of phosphatase.

Where did you get this concept ?? Would you please like to share your source??Thanks in advance .

Best of luck

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young_doc
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09/21/06 - 04:51 PM

"Binding of cGMP to cGMP-dependent protein kinases (PKG) or cGMP dependent ion channels results in reduction of intracellular calcium, via calcium sequestration, and activation of myosin light chain phosphatases causing diminution of smooth muscle contractility."

So i guess it's both Ca-sequestration AND de-phosphorylation of Myosin Light Chain

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young_doc
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09/21/06 - 04:52 PM

I don't have a specific "source". Just google search it. The sources are endless...

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