The Enteric Nervous System

Question 1

what is the clinical significance of the ENS?

Answer 1

many disease of GI tract are implicated in the ENS and some CNS disorders share links with ENS

Question 2

what is the basic organisation structure of the ENS?

Answer 2

there is a plexus which is made of ganglia and internodal strands. within these are neurons, glial cells, and axon bundles

Question 3

what are the two main plexus’ involved in ENS function and what do they control?

Answer 3

myenteric plexus which controls gut motility and the submucosal plexus that regulates digestive secretions

Question 4

what are the three motor patterns present in the ENS?

Answer 4

accomadation which is physical distention, peristalsis which is a rapid local reflex, and migrating motor complex (MMS) which is high amplitude, rhythmis, propagating waves for slow transmit

Question 5

how can we inhibit the CMMC?

Answer 5

by elongation (a longitudinal stretch)

Question 6

what is the role of 5-HT in the ENS?

Answer 6

to evoke CMMCs (initiation)- this process involves a range of serotonin receptors

Question 7

what are the two types of IBS?

Answer 7

IBS-C and IBS-D

Question 8

what is the pathology of IBS-C?

Answer 8

decreased serotonin levels and dysfunctional TPH1 synthesis

Question 9

what is the pathology of IBS-D?

Answer 9

increased serotonin and 5-HT3R levels and reduced SERT (serotonin uptake transporter)

Question 10

which two drugs can treat IBS-C?

Answer 10

SSRIs and tegaserod

Question 11

which three drugs are used to treat IBS-D?

Answer 11

alosteron, ondansetron, and LX-1031