Gario
Forum Junior
Topics: 14
Posts: 35
|
I wanna know why ganglionic blocking drugs cause urinary retention.
(Goodman and Gilman's the Pharmacological Basis of Therapeutics, 10/e, Table 9-4)
Any opinion will be appreciated.
Thanks.
Gary
|
| mjl1717
Forum Hero
Topics: 956
Posts: 5,452
|
First they compete with Ach to bind with nicotinic receptors of both parasympathetic and sympathetic ganglia.
**Must remember which division of the autonomic nervous system predominates.
*In the Urinary system parasympathetic predominates (urination)/thats blocked so we have urinary retention
*hint I usually think of parasympathetic as "housekeeping" except in
arteries,veins and sweat glands
In general this category is old fashion because it lacks selectivity!!
___________________
Smell the coffee! "Is That an Osler move??"
|
| Gario
Forum Junior
Topics: 14
Posts: 35
|
Thank you very much, mjl1717.
You have answered many of my questions.
That information were very helpful.
I still have some more detailed questions.
Could you do me a favor?
Q1.Goth said that ganglionic blocking agents cause the reduction of smooth muscle of GI and urinary tracts, causing constipation and dysuria. The "smooth muscles of the urinary tract" include trigone, internal sphinctor, detrusor muscle of bladder? Are there other muscles also included?
Q2. The smooth muscles above are predominated by which division of the ANS and what is the ANS effect individually? (Detrusor muscle is predominated by parasym. system, causing contraction. The parasympathetic tone of trigone and internal sphinctor is almost equal to their sympathetic tone.)
Q3. So we can draw a conclusion that...(After administrating ganglionic blocking agents, the bladder will express the sympathetic effect, urinary retension, which is the same as what mjl1717 said.)
Thank you again!
Gary
|
| mjl1717
Forum Hero
Topics: 956
Posts: 5,452
|
1) Thats correct. the detrusor is also called the pubovesical m. Must add the external urethral sphincter is under voluntary control with the pudendul
n.
Think of urinary retention as sympathetic (internal sphincter contracts)
But when the internal sphincter opens the ext. sphincter simultaneously relaxes.
Ironically I think the detrusor is contracted during micturition
*The main point with urination(parasympathetic ) the sphincters relax and the detrusor contracts via hypogastric :arrow: vesical plexus.Hope this helps.
___________________
Smell the coffee! "Is That an Osler move??"
|
| Gario
Forum Junior
Topics: 14
Posts: 35
|
Good!
I need to do more work on the subject.
You really indicate the right point.
Thank you very much.
Gary
|
|
| |
| | | | | |
