Vasopressin 2

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Vasopressin 2

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DRFP
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11/03/07 - 02:29 PM

Hi, I have been so frustrated with NBME

Some Q's are so out there and crazy

Can anyone tell me what is Vasopressin 2 and what it does I have been searching and just cannot get an answer
there was a Q on NBME 3 1 that you had to tell what would happen if Vasopressin 2 was not working.

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silver
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11/03/07 - 02:44 PM

it's basically ADH ...this is what i found:-

http://www.3dchem.com/molecules.asp?ID=356

http://en.wikipedia.org/wiki/Arginine_vasopressin...

http://en.wikipedia.org/wiki/Vasopressin

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new_n_lost
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11/03/07 - 05:42 PM

Three known receptors bind ADH at the cell membrane: V1a, V1b (also known as V3), and V2. The vasopressin (AVP, ADH) receptor subtypes belong to the G protein��"coupled receptor superfamily. The V1a and V1b receptors signal by activation of phospholipase C and elevation in intracellular calcium, which, in turn, stimulates protein kinase C.

V1a subtype is ubiquitous and found on cells, such as vascular smooth muscle cells, hepatocytes, platelets, brain cells, and uterus cells. V1b receptors are found predominantly in the anterior pituitary.

V2 receptors are coupled to adenylate cyclase, causing a rise in intracellular cyclic adenosine monophosphate (cAMP), which serves as the second messenger. V2 receptors are found predominantly in the principal cells of the renal collecting duct, where they mediate antidiuretic response. V2 receptors are also found in endothelial cells and induce the secretion of von Willebrand factor.

ADH activates the V2 receptor on the basolateral membrane of the principal cells of the renal collecting duct. This activates cyclic adenosine monophosphate through heterotrimeric G proteins, which results in insertion of aquaporin-2 water channels in the luminal membrane, thus making it more permeable to water.

from NEJM.

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new_n_lost
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11/03/07 - 05:48 PM

I hope this diagram will help u understand more.

Attached Files:
Physiology of Water Homeostasis in Humans.doc (85 KB, 14 downloads)

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DRFP
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11/03/07 - 10:15 PM

Thanks everyone I knew about ADH and such just it seems at times some terms where not taught (Or I was asleep that time LOL)

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