Pharmacology question: ANS and GIT control

[Sipadan]

Can someone please give me an answer to what appears to be a straightforward question:

If sympathetic activity generally reduces gut motility why do people get the ‘runs’ if nervous?

Having a slight disagreement with a clinical demonstrator.

Thanks

[honeyglaze]

well i have written down

increased stimualtion of sympathethic system increases mucus secretion which increases osmosis into the large intestine which = runs!

[dantheripper]

plus...

If the food is not being digested due to the sympathetic influences on digestion, then the osmolarity in the gut will remain relatively more negative and therefore more water will remain in the actual intestinal lumen?

[rjm]

decreased smooth muscle activity --> decreased mixxing of intestinal contents --> decreased absorption.

[Sipadan]

Spot on answers everyone. Our clin dem didn't mention the osmosis bit, so 2 + 2 seemed to make 5 at the time. All clear now, thanks.

[Medic]

Being nervous has also been associated with 'peeing in ur pants' but Micturition is parasympatheticaly controlled. So how can that be explained?