By coincidence I was at a lecture today on the digestive system, and there was quite a lot of talk about saliva etc.
Basics:
Both the Sympathetic (S) and ParaSympathetic (PS) branches of the autonomic nervous system activate salivary flow from the salivary glands, but do it in different ways. PS activation result in the watery outflow (with salts etc) while S activate protein & enzyme release.
When stressed, S kicks in as usual, and the protein/enzyme release gets a boost. But stress also causes vasoconstriction (blood vessel muscles contract) in the salivary gland area, resulting in much less blood flow, which limits the glands' watery outflow. This is what causes the extremely dry mouth during stressful situations, for example when a chronic halitosis sufferer is in an enclosed space and the fight/flight mechanism kicks in.
To counteract vasoconstriction, the glands can secrete kallikrein, which becomes bradykinin, which opens up vessels again. Maybe if we can find medication with bradykinin it can help..?
But the main thing would be to try and *not* react to stressful situations. Easier said than done...
