OBJECTIVE: To research the toxicokinetics features of ivabradine hydrochloride and the accumulation situation of its products in Beagles, during one month oral administration with it.

ObjectiveTo clarify the relationship between intestinal flora and intestinal motility in rats with slow transit constipation （STC） and qi stagnation syndrome by conducting a pseudo-sterile experiment and fecal microbiota transplantation （FMT） technology. MethodsTwenty-four Wistar rats were randomly divided into normal group （n=6）， STC with qi stagnation pattern group （n=6） and pseudo-sterile group （n=12）. In the STC group with qi stagnation pattern， 3 mg/kg of loperamide suspension by intragastric administration combined with tail clamping stimulation were performed to establish the rat model of STC with qi stagnation pattern. After successful modeling， fresh feces from the rats in the STC with qi stagnation pattern group and the normal group were collected to prepare 100 mg/ml of fecal bacterial suspension. In the pseudo-sterile group， the antibiotic cocktail method was used （a mixed antibiotic suspension containing bacitracin， streptomycin sulfate， and neomycin sulfate at 20 mg/ml each was administered intragastrically） to establish pseudo-sterile rats model. After successful modeling， the rats were randomly divided into normal fecal bacterial liquid group and STC with qi stagnation pattern fecal bacterial liquid group， with six rats in each group， and then were given 10 ml/kg of the prepared corresponding rat fecal bacterial suspension by gavage. Rats in STC with qi stagnation pattern group were given an equal volume of sterile water by gavage. All groups were administered once a day for 7 consecutive days. The small intestinal propulsion rate of the STC with qi stagnation pattern group， the normal fecal bacterial liquid group， and STC with qi stagnation pattern fecal bacterial liquid group were compared. ELISA method was used to detect serum 5-hydroxytryptamine （5-HT） levels. Immunohistochemistry was used to detect the positive expression levels of 5-hydroxytryptamine 3 receptor （5-HT3R） and 5-hydroxytryptamine 4 receptor （5-HT4R） in colon tissue. Western blot method was used to detect the protein expression levels of tryptophan hydroxylase 1 （TPH1）， tryptophan hydroxylase 2 （TPH2）， serotonin transporter （SERT）， and monoamine oxidase A （MAO-A） in colon tissue. ResultsCompared to those in the normal fecal bacterial liquid group， the small intestinal propulsion rate， serum 5-HT level， positive expression of 5-HT3R and 5-HT4R in colon tissue， and protein expression of TPH1， TPH2， SERT and MAO-A significantly decreased in the STC with qi stagnation pattern group and STC with qi stagnation pattern fecal bacterial liquid group （P＜0.05）. There was no statistically significant difference in the indicators between the STC with qi stagnation pattern group and STC with qi stagnation pattern fecal bacterial liquid group （P＞0.05）. ConclusionThe intestinal flora in STC rats with qi stagnation pattern can lead to a slowdown in intestinal transmission function， whose mechanism may be related to intestinal motility disorders affected by the synthesis， transport， metabolism and other pathways of 5-HT.