The Reasearch About Effects Of EGb On Gastraintestinal Motility And It's Mechanisms

Objective: To investigate the effects of ginkgo biloba extract (EGb) on gastrointestinal motility from integrate-organ-cell-molecule levels and reveal the mechanisms of EGb how to regulate colon functions and explore the potential role of gut peptide in stress-inducing colonic motor disorder.Methods: 1.Using blue dextran 2000 (DB 2000) as a marker, we observed the effects of EGb and stress on gastric emptying and motor activity of small intestine. 2. The effects of EGb and Flavonoids on isolated colon motility were separately observed. 3. Smooth muscle cells were isolated from the colon of the guinea pig and the response to EGbwas observed. 4. The contents of VIP, SP, NO in plasma and colonic muscle layer weremeasured by radiommunoassay (RIA) and chemical method.Results: 1. Motor activity of small intestine in BALB/c mice was inhibited by EGb atdosage of 2.0 mg/L.2. EGb can induce colon biphasic actions: inhibition and excitation, the first is primary. EGb could antagonize the effect stimulated by ACh and 5-HT. And it could increase the inhibitory effect of VIP and perfusion by free Ca2+ Krebs solution. But EGb have noeffect on Adr, GABA and Atropine. Flavonoids could inhibite significantly the spontaneous contraction of colon dose-dependently.3. Isolated smooth muscle cells were obstaind. When incubated with 0.11, 0.22 , 0.44,0.88, 1.75 and 3.5 g-L-1 of EGb , the most relaxatant response of smooth muscle cells that is in 1.75 g-L-1 is 12.8% (P < 0.05). EGb (1.75 g-L-1) significantly inhibited 44.1%of contraction response of colonic smooth muscle cells caused by ACh (P < 0.01).Forskolin increased relaxatant effect of EGb on colonic smooth muscle cells in guinea pig to 8.9% compared with effect of only EGb.4. Cold-restraint stress can enhance significantly gastric emptying and inhibite motor activity of small intestine in rats. EGb can inhibit the sooner gastric emptying and enhance the slower motor activity of small intestine induced by cold stress.5. SP levels in blood and SP, VIP in colon of EGb group were higher than the control groups (P < 0.05 or P < 0.01), while VIP levels in blood and NO levels in colon and blood were no change obviously (P > 0.05). SP and NO levels in blood of cold stress were significantly higher (P < 0.01) ; SP , VIP levels in colonic layers and VIP levels in blood of cold-restraint stress were significantly lower than the control group (P < 0.05 or P < 0.01), while NO levels in colonic layers of cold stress didn't change. In the stressgroups after being treated with EGb , SP in blood improved apparently , while SP , VIPin colon and NO in blood decreased. Conclusion:1. EGb has a direct relaxatant effect on the colonic smooth muscle cells of guinea pig,and this effect of EGb may mediate partly by cAMP messenger pathway . SP , VIP andNO levels in colon and blood of cold stress may be related to the gastrointestinal motility disorders presented in cold stress rats;2. EGb may regulate the motility of colon of Guinea pig through 5-HT ACh, VIP,Ca 2+ , M-receptor and direct effect on the intestinal muscle. Flavonoids has restrainingeffect on isolated colon movement, may be one of valid elements of EGb which inhibits colonic contraction;3. EGb can inhibit motor activity of small intestine in BALB/c mice and Wistar rats;4. EGb can change the levels of SP, VIP , NO in colon and blood of normal and stressrats, to presume that SP, VIP,.NO are related with the effect of EGb to normal and stress rats .