Nitroglycerine Mechanism of Action (Nitric Oxide)? - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 791
Threads: 76
Thanked 673 Times in 317 Posts
Reputation: 691
Drug Nitroglycerine Mechanism of Action (Nitric Oxide)?

Nitroglycerine is a cardiovascular medication that is commonly used in case of angina. Which of the following is the mechanism of action of this medication that causes vasodilation of vascular smooth muscle?

1) Binding of NO receptors
2) Competitive inhibition of NO receptors
3) Production of NO
4) Release of NO
5) Sequestration of NO
Reply With Quote Quick reply to this message



  #2  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,406
Threads: 118
Thanked 647 Times in 409 Posts
Reputation: 657
Default

C. Production of NO
__________________
"inflammable means flammable!? What a country."
Reply With Quote Quick reply to this message
  #3  
Old 05-01-2012
DocSikorski's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,353
Threads: 94
Thanked 877 Times in 507 Posts
Reputation: 890
Default

wording of answers is weird or incomplete... release from where? production from where? release of NO from the drug? or production of NO by the drug... or release NO from... eh from smooth muscle or something?
__________________
Ambition is a dream with a V8 engine. EP
Reply With Quote Quick reply to this message
 
  #4  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,039
Threads: 189
Thanked 570 Times in 323 Posts
Reputation: 580
Default my answer

c)
nitrates are prodrugs.
Reply With Quote Quick reply to this message
  #5  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,406
Threads: 118
Thanked 647 Times in 409 Posts
Reputation: 657
Default

nitrates are NO precursors.
__________________
"inflammable means flammable!? What a country."
Reply With Quote Quick reply to this message
  #6  
Old 05-01-2012
K06100's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 730
Threads: 90
Thanked 458 Times in 289 Posts
Reputation: 468
Default D

Quote:
Originally Posted by anomali View Post
Nitroglycerine is a cardiovascular medication that is commonly used in case of angina. Which of the following is the mechanism of action of this medication that causes vasodilation of vascular smooth muscle?

1) Binding of NO receptors
2) Competitive inhibition of NO receptors
3) Production of NO
4) Release of NO
5) Sequestration of NO
this is what i thought.....though not clearly given
__________________
Try Not To Become A Man Of Success But A Man Of Value.
Reply With Quote Quick reply to this message
  #7  
Old 05-01-2012
USMLE Forums Master
 
Steps History: Not yet
Posts: 674
Threads: 264
Thanked 963 Times in 394 Posts
Reputation: 973
Send a message via Yahoo to ricko335
Default

Gtn relax vascular smooth mucles by intracellular conversion to nitrite ions and then to nitric oxide which in turn activates guanyl cyclase and cgmp SO THE ANSWER IS PRODUCTION OF NO
Reply With Quote Quick reply to this message
  #8  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 791
Threads: 76
Thanked 673 Times in 317 Posts
Reputation: 691
Default Its a usmlerx question...very ambiguous though

I choose the option C like most of u guys but to my surprise the answer was gtn causes release of stored NO.....

NO is a gas right??? so how can it be stored in a vesicle or any membrane since gases are highly lipid soluble.

and

Can anyone clarify the exact MOA of gtn???? does it itself gets converted to NO, or stimulate some enzyme to produce NO or it releases NO from some site or vesicle( like explained in usmlerx).....
Reply With Quote Quick reply to this message
  #9  
Old 05-01-2012
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 194
Threads: 21
Thanked 147 Times in 85 Posts
Reputation: 157
Default

NO is released from NG, through an enzyme which is found only in the veins - thats the reason NG's are potent vasodilators of the venous side and not the arterial side.
Reply With Quote Quick reply to this message
  #10  
Old 05-01-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,039
Threads: 189
Thanked 570 Times in 323 Posts
Reputation: 580
Default disagree with usmlerx

I disagree with usmlerx answer... based on 2 sources:

1) their explanation is contradictory to what they say in Kaplan videos...
I just played the video and Dr. Raymond said: "Nitroglycerin is a prodrug that will be eventually catabolized to NO"

the NO pathway is in the attachment.

ALSO:

2) "GTN is a prodrug which must first be denitrated to produce the active metabolite nitric oxide (NO). Nitrates which undergo denitration within the body to produce NO are called nitrovasodilators and their denitration occurs via a variety of mechanisms."

source: http://en.wikipedia.org/wiki/Glycery...nism_of_action
Attached Thumbnails
Nitroglycerine Mechanism of Action (Nitric Oxide)?-no-pathway.jpg  
Reply With Quote Quick reply to this message
The above post was thanked by:
anomali (05-01-2012)



Reply

Tags
Figures-, Molecular-Biology-, Pharmacology-, Step-1-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mechanism of action! hope007 USMLE Step 1 Forum 0 10-08-2011 11:23 PM
Nitroglycerine Mechanism of Action! l2sweedan USMLE Step 1 Forum 6 10-03-2011 02:58 AM
The Mechanism of action of Gastrin? ricko335 USMLE Step 1 Forum 11 09-16-2011 09:23 AM
Mechanism of action of these drugs... bebix USMLE Step 1 Forum 5 06-20-2011 04:57 AM
Fibrates Mechanism of action? LionofJudo USMLE Step 1 Forum 5 07-23-2010 06:22 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)