Posted by ed_uk2010 on December 14, 2014, at 23:36:25
In reply to Re: Caution, posted by linkadge on December 14, 2014, at 20:12:40
Hi Link,
Great post.
True about amitriptyline - very messy drug!
.....
Muscarinic receptors are confusing in general.
I think you could be right about M1 receptors. I know they are thought to be involved in memory. M1 receptors also have a role in gastric acid and salivary secretion. I believe all the anticholinergics used in Parkinson's/antipsychotic side effects are M1 antagonists, but not selective.
M2 receptors are important in regulating heart rate. In certain areas of the brain, they are apparently autoreceptors inhibiting further acetylcholine release.
M3 receptors control contraction and secretion respectively in the bronchi, bladder and salivary glands. In the brain they may regulate nausea/vomiting/motion sickness. I assume Scopoderm and various other anticholinergic and combined antihistamine/anticholinergic antiemetics work here!
M4 receptors are thought to be involved in motor control.
M5 - Don't know.
>AFAIK, Cogentin (benztropine) is also a dopamine reuptake inhibitor, which probably contributes to its abuse liability.
I've read that too. May also apply to other anticholinergic antiparkinson drugs.
> Hi Ed,
>
> I actually prefer a pure anticholinergic to something like amitriptyline. Amitriptyline is a good medication, but it really whacks you out (antihistamine + anticholinergic + all the rest).
>
> I think its the M1 receptors that exert inhibitory control over the mesolimbic dopaminergic system. Mice lacking the M1 receptors display a depression resistant phenotype. The M1 receptors are important the consolation of emotional memory. For instance, blocking the m1 receptors will prevent the enhanced REM response in mice to predator exposure - as well as subsequent emotional disturbance.
>
> AFAIK, Cogentin (benztropine) is also a dopamine reuptake inhibitor, which probably contributes to its abuse liability.
>
poster:ed_uk2010
thread:1074099
URL: http://www.dr-bob.org/babble/20141120/msgs/1074219.html