Effect Of GBBE On The Contraction Of Rabbits Isolated Longitudinal Muscle Strips Of Duodenum

ObjectivesTo investigate the effects of GBBE(Ginkgo biloba b element) on the isolated duodenal smooth muscle from rabbits and its possible mechanism.MethodsTo make the isolated duodenal smooth muscle strip, put the samples into the smooth muscle bath and incubate with the mixed gas including95%O2and5%CO2, and then add the different concentration GBBE, we observe the effects of GBBE on the amplitude, tension and frequency of spontaneous contraction and the spasmous contraction induced by ACh(acetylcholine) in the isolated duodenal smooth from rabbit muscle; According to the study protocol, we put the adrenergic receptor blockers-propranolol and Phentalamine, PG biosynthesis inhibitors-Indomethacin, ATP sensitivity K+channel blockers-Glibenclamide and cGMP channel blocker Methylene blue and incubate to survey the effects of GBBE on the the spasmous contraction induced by ACh in the isolated muscle strip. Mereover, we add Verapamil in the bath to observe the relationship between GBBE and calcium ion.ResultsGBBE (fine concentration:3×10-3M,10-2M and3×10-2M) had no effect on the amplitude, tension and frequency of spontaneous contraction, but the concentration of3×10-3M,10-2M and3×10-2M of GBBE could inhibit the amplitude and tension of spontaneous contraction and had no effect on frequency; GBBE could antagonism spasmodic contraction induced by ACh in the isolated duodenal smooth muscle, and the more the concntration is, the stonger the inhibitional effect is; The mechanism of relaxation of GBBE on the isolated duodenal smooth muscle was no relation with adrenergic receptor-mediated relaxation and PG channel, but had a tight relationship with ATP-sensitive K+channel opening, cGMP-related relaxation. In relation with Ca2+, relaxation of GBBE on the isolated duodenal smooth muscle was similar with Verapamil (an known Ca2+antagonist) was associated with the inhibition of potential dependent channel opened by KCl and release of Ca2+from sarcoplasm reticulum induced by ACh.ConclusionGBBE can relax the isolated duodenal smooth muscle from rabbits and antagonism spasmodic contraction. Relaxation of GBBE is related with ATP-sensitive K+channel, cGMP-related pathway and lower Ca2+concentration in intracytoplasm.