Autonomic Pharmacology Concept! - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
USMLE Articles
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

Thread Tools Search this Thread Display Modes
Old 07-06-2012
USMLE Forums Scout
Steps History: 1+CK+CS
Posts: 32
Threads: 19
Thanked 30 Times in 3 Posts
Reputation: 40
Drug Autonomic Pharmacology Concept!

I have a question regarding autonomic pharmacology.
I have often seen the receptor/neurotransmitter distribution for Sympathetic, parasympathetic and skeletal muscle. Based on what i have seen, I am assuming that either Acetylcholine or nicotine can stimulate the Nn receptors located at the ganglions for both sympathetic and parasympathetic, leading to further neurotransmitter release at level of effector organ.

However, why does this not make nicotine/Varenicline, a ganglionic agonist that stimulates BOTH symp./parasymp.?

So, why do not organophosphates, (that I assume, simply prolong ACh effect duration), also cause activation of BOTH symp./parasymp., since they are basically raising active Ach levels, irrespective of location?

Yet, organophosphate poisoning produces effects typical of Parasymp. agonism. Why is this occuring and not the dual activation of both autonomic nervous system arms cancelling each other out?
Is this due to some kind of predominance or that drugs are peripheral action only? (because the diagrams list ganglia for both symp./parasymp. outside the vertebral canal)

Even then, why does not the prolonged Ach not affect the exclusively symp. controlled actions like ionotropy for heart? (as I have never read Positive ionotropy as a side effect of organophosphate poisoning).

I know I have asked a considerable number of questions but I would greatly appreciate an early response as my preparation has been halted specifically due to this question.
Reply With Quote Quick reply to this message



Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
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.
Where you live. Leave blank if you don't want to tell.


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
How to answer Autonomic Pharmacology Questions mle2resident USMLE Step 1 Forum 10 10-06-2014 02:06 AM
Important concept aiminghigh USMLE Step 1 Forum 3 12-11-2011 10:38 PM
NBME 11 concept. donofitaly USMLE Step 1 Forum 3 08-21-2011 12:06 PM
A-a gradient concept kemoo USMLE Step 1 Forum 4 04-30-2011 06:51 PM
New heart , autonomic supply cut off laxitjn USMLE Step 1 Forum 4 03-07-2011 10:06 AM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 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)