Dry Mouth - Stimulants

[blog]

hi, I don't seem to be very good at using search engines, and you people are pretty brainy. Basically I want to know what is the mechanism of action that causes dry mouth when certain stimulants are used.

I know constriction of blood vessels occur, does this reduce blood flow to the saliva glands, which severely impairs their ability to produce saliva?

[WarpedAstro]

Hey...I am not that brainy either, but I'm learning as I go, I have no answer for your question, my guess is just keep drinking more water, you will be fine. Goodluck with your research, otherwise check out one of these medical websites.

[Torsten]

this is a little beyond me too (without having my books handy), but I thought that usually the transmitter acetylcholine is involved. I just can't remember which way it goes, if the increase of acetylcholine or the decrease is the cause.

in any case, to 'keep on drinking' may be very dangerous. never drink more than 1000ml per hour is sweating excessively, and no more than 500ml if not sweating much. (remember, Anna Wood died from drinking too much water!!!).

these are upper figures!

if your muscles start cramping then your brain is likely to be doing the same. electrolytes are needed!!

[spaced]

Blog, I couldn't comment on the exact physiology behind the opperation of the salivary glands although I'm sure the information would be freely available either on the net or from an anatomy / physiology textbook.

As for the neurotransmitters involved - adrenaline / noradrenaline are chemicals associatied with stress (good and bad), are produced via the sympathetic nervous system and tend to be associated with a dry mouth. Compounds that act via stimulating the SNS ie sympathomimetics (eg ephedrine) thus tend to dry out the mouth (as well as having many other actions).

This mouth drying effect of adrenaline and the SNS is opposed by the mouth moistening effect of the parasympathetic nervous system (PNS) which stimulates the salivary glands through the action of acetylcholine (as well as having many other functions). The PNS does this as one of its main functions is to assist with the digestion of food. Drugs which stimualte the PNS such as muscarine from certain mushrooms lead to higher rates of salivary production, a characteristic which can be useful in determining what type of mushrooms someone has eaten when the mushrooms are either not available or their identity can not be confirmed. (if you do intend to eat wild mushrooms always keep a few spare for identification purposes in case you later end up in hospital). Conversly drugs which block acetylcholine or have an anticholinergic effect dry out the mouth. This is a very long list and includes compounds found in nature such as atropine and scopolamine and lots of synthetic compounds such as antipsychotics and some of the older style antidepressants.

Opioids tend to produce a mouth drying effect as well. These drugs operate on a different system. Chronic use of heroin and substitutes such as methadone is often associated with higher rates of dental complications (the enzymes in saliva have a protectant effect on the teeth and gums). The same can be said for certain psychiatric drugs.