(C) Low magnification images of the distribution of 5-HT and 5-HT4R positive cells in the descending colon of control human tissue.
(D) Low magnification images showing the distribution of 5-HT and 5-HT4R positive cells in the sigmoid colon of control human tissue.
(E) Low magnification images showing the distribution of 5-HT and 5-HT4R positive cells in the rectum of control human tissue.