Effects of Graded Acetylcholine Infusions on Intestinal Motility, Volume, and Blood Flow

Abstract

Low ACH doses increased intestinal blood flow to about a half of the maximal level while higher doses again decreased flow. Intestinal motility increased proportionally to the ACH doses and, at higher doses, displayed particularly marked rhythmicity with intraluminal pressures varying between about 30 and 200 mm Hg. It is suggested that the decreased blood flow at higher ACH doses is a mechanical consequence of this strong motor activity. Concomitant with this increased motility and decreased blood flow, intestinal volume increased in a stepwise manner. This seems, besides a possible secretory response to ACH, to reflect an outward capillary filtration caused by a mechanical interference with venous outflow when contractions of the muscular coat squeeze the piercing veins. During pathological conditions it is possible that the intestinal motility might be intense enough to interfere with the blood flow.

Key-words:

• Acetylcholine
• intestinal blood flow
• intestinal motility