The enteric nervous system plays the most important role in mediating serotonergic effects on gut function. However, researchers originally thought that enterochromaffin cells played the most important role because
A) experiments with knockout mice suggested greater involvement of enterochromaffin cells.
B) of the sheer number of enterochromaffin cells in the gut.
C) of the high density of 5-HT in enterochromaffin cells.
D) enterochromaffin 5-HT is released directly into the bloodstream.

Question

Quizplus · Accepted Answer

Enterochromaffin cells release serotonin, which accounts for about 95% of the body's serotonin, and have a high density of the neurotransmitter. However, the enteric nervous system has been found to play a more crucial role in mediating serotonergic effects on gut function. Experiments with knockout mice have also shown that the enteric nervous system is more important in this regard. The number of enterochromaffin cells in the gut or the release of enterochromaffin 5-HT directly into the bloodstream are not as relevant for their role in mediating serotonergic effects on gut function.

The Enteric Nervous System Plays the Most Important Role in Mediating