Locality-dependent descending reflex motor activity in the anal canal--cholinergic and nitrergic contributions in the rat model.

Aim: Since the distal part of the intestine is targeted by a wide range of pathogens, the motility of the recto-anal region has been the object of many experimental and clinical observations. In this study, we investigated descending motor responses in the anal canal as a measure of the activation of autonomic reflex pathways underlying evacuatory recto-anal activity.

Methods: The partitioned organ bath method was used to register motor responses of the anal canal as induced by balloon distension of the rectum in isolated rat recto-anal preparations.

Ascending and descending reflex motor activity of recto-anal region-cholinergic and nitrergic implications in a rat model.

The implications of cholinergic and nitrergic transmissions in ascending and descending reflex motor pathways of recto-anal region in rat model were evaluated using: (i) electrical stimulation; (ii) triple organ bath; and (iii) morphological techniques. Electrical stimulation to anal canal induced simultaneous ascending contractile responses of longitudinal and circular muscles of proximal rectum, local contraction of anal canal or contraction followed by relaxation of internal anal sphincter when external sphincter was dissected off. The stimulation of proximal rectum elicited local contractions of both rectal layers and descending contractions of internal sphincter or anal canal.