Characteristics of long distance contraction in rat colon in different conditions

Objective: To explore the features of long distance contraction (LDC) of rat colon in different conditions. Methods: Forty rats were divided randomly and equally into three groups. Group 1: YE group, giving yeast extract (YE) and Normal Saline (NS) respectively in 3 consecutive days through gavage administration acutely; Group 2: TTX and bethanechol group, after TTX administration, adding bethanechol to stimulate myogenic components to generate LDC; Group 3: proximal and distal LDC group, the pan-colon was separated into two parts from the middle. The spatiotemporal map was made by measuring the diameter changes of the colon in the organ bath. Results: YE increased the contraction length of LDC and made the contraction slower; The muscarinic acetylcholine receptor 1 agonist Bethanechol could recover LDC after the neurotoxin TTX, and make LDC huge and slow-propagating; LDC could also appear independently in the distal colon without the proximal colon, and its speed was faster and contraction length shorter compared with LDC in the proximal colon. Conclusion: Nutrients, drugs and so on can change the characteristics of LDC, which mainly reflects the myogenic control and pacemaker function of the colon, thus exerts its comprehensive regulating effect to the gastrointestinal tract.