输尿管的蠕动生理和压力关系

输尿管的主要功能是输送尿液至膀胱,这种生理作用和它的蠕动特性密切相关。由于蠕动而推进的尿液灌流,正常情况下是和输尿管腔内压力成一定生理关系。这种尿液灌流一压力关系,是近十几年来出现的对上尿路梗阻新的诊断方法Whitaker试验的生理学基础。因此有必要重新认识新近对输尿管组织形态和生理生化等各方面的研究进展,提高对输尿管蠕动生理和压力关系的认识。

Effect of psychological stress on gastric motility assessed by electrical bio-impedance

AIM:To evaluate gastric motility using electrical bioimpedance(EBI) and gastric changes as a result of stress induced by psychological tests.METHODS:A group of 57 healthy women,aged 40-60 years,was recruited,and a clinical history and physical examination were performed.The women were free from severe anxiety,chronic or acute stress,severe depression,mental diseases and conditions that affect gastric activity.The women were evaluated under fasting conditions,and using a four-electrode configuration,the gastric signals were obtained through a BIOPAC MP-150 system.The volunteers were evaluated using the following paradigm:basal state,recording during the Stroop Test,intermediate resting period,recording during the Raven Test,and a final resting period.We analyzed the relative areas of the frequency spectrum:A1(1-2 cpm),A2(2-4 cpm),A3(4-8 cpm),and A4(8-12 cpm),as well as the median of area A2 + A3.The data were analyzed by an autoregressive method using a Butterworth filter with MatLab and Origin.Analysis of variance(ANOVA) and Friedman ANOVA(for nonparametric variables) were performed;in addition,pairs of groups were compared using the T dependent and Wilcoxon T tests.RESULTS:The results of the main values of area A2 were not significantly different comparing the five steps of the experimental paradigm.Nevertheless,there was a tendency of this A2 region to decrease during the stress tests,with recuperation at the final resting step.When an extended gastric region was considered(1-4 cpm),significant differences with the psychological stress tests were present(F = 3.85,P = 0.005).The A3 region also showed significant changes when the stress psychological tests were administered(F = 7.25,P < 0.001).These differences were influenced by the changes in the adjacent gastric region of A2.The parameter that we proposed in previous studies for the evaluation of gastric motility by electrical bio-impedance(EBI) was the median of the area under the region from 2 to 8 cpm(A2 + A3).The mean values of these frequencies(median of the A2 + A3 area) with the stress test showed significant changes(F = 5.5,P < 0.001).The results of the WilcoxonT test for the A4 area parameter,which is influenced by the breathing response,changed significantly during the Raven stress test(P < 0.05).CONCLUSION:We confirm that the gastric response to acute psychological stress can be evaluated by short-term EBI.

Postprandial transduodenal bolus transport is regulated by complex peristaltic sequence

AIM: To study the relationship between the patterns of postprandial peristalsis and transduodenal bolus transport in healthy subjects. METHODS: Synchronous recording of chyme transport and peristaltic activity was performed during the fasting state and after administration of a test meal using a special catheter device with cascade configuration of impedance electrodes and solid-state pressure transducers. The catheter was placed into the duodenum, where the f irst channel was located in the f irst part of the duodenum and the last channel at the duodenojejunal junction. After identif ication of previously def ined chyme transport patterns the associated peristaltic patterns were analyzed. RESULTS: The interdigestive phase 3 complex was reliably recorded with both techniques. Of 497 analyzed impedance bolus transport events, 110 (22%) were short-spanned propulsive, 307 (62%) long-spanned propulsive, 70 (14%) complex propulsive, and 10 (2%) retrograde transport. Short-spanned chyme transports were predominantly associated with stationary or propagated contractions propagated over short distance. Long-spanned and complex chyme transports were predominantly associated with propulsive peristaltic patterns, which were frequently complex and comprised multiple contractions. Propagated double wave contraction, propagated contraction with a clustered contraction, and propagated cluster of contractions have been identif ied to be an integralted part of a peristaltic sequence in human duodenum. CONCLUSION: Combined impedancometry and manometry improves the analysis of the peristaltic patterns that are associated with postprandial transduodenal chymetransport. Postprandial transduodenal bolus transport is regulated by propulsive peristaltic patterns, which are frequently complex but well organized. This f inding should be taken into consideration in the analysis of intestinal motility studies.

Mangiferin,a natural xanthone,accelerates gastrointestinal transit in mice involving cholinergic mechanism

AIM： To investigate the effects of mangiferin on gas- trointestinal transit （GIT） in normal and constipated mice, together with the possible mechanism.METHODS： Intragastrically-administered charcoal mealwas used to measure GIT in overnight starved Swiss mice. In the first experiments, mangiferin （3 mg/kg, 10 mg/kg, 30 mg/kg, and 100 mg/kg, po） or tegaserod （1 mg/kg, ip） were administered 30 min before the char- coal meal to study their effects on normal transit. In the second series, mangiferin （30 mg/kg） was tested on delayed GIT induced by several different pharma- cological agonists （morphine, clonidine, capsaicin） or antagonists （ondansetron, verapamil, and atropine） whereas in the third series, mangiferin （30 mg/kg, 100 mg/kg and 300 mg/kg） or tegaserod （1 mg/kg） were tested on 6 h fecal pellets outputted by freely fed mice. The ratio of wet to dry weight was calculated and used as a marker of fecal water content. RESULTS： Mangiferin administered orally significantly （P 〈 0.05） accelerated GIT at 30 mg/kg and 100 mg/kg （89% and 93%, respectively）, similarly to 5-hydroxytrypta- mine4 （5-H%） agonist tegaserod （81%） when compared to vehicle-treated control （63%）. Co-administered man- giferin （30 mg/kg） totally reversed the inhibitory effect of opioid agonist morphine, 5-HT3-receptor antagonist ondansetron and transient receptor potential vanilloid-1 receptor agonist capsaicin on GIT, but only to a partial extent with the GIT-delay induced by ~2-adrenoceptor agonist clonidine, and calcium antagonist verapamil. However, co-administered atropine completely blocked the stimulant effect of mangiferin on GIT, suggesting the involvement of muscarinic acetylcholine receptor activation. Although mangiferin significantly enhanced the 6 h fecal output at higher doses （245.5±10.43 mg vs 161.9±10.82 mg and 227.1±20.11 mg vs 161.9±10.82 mg of vehicle-treated control, at 30 and 100 mg/ kg, P 〈 0.05, respectively）, the effect of tegaserod was more potent （297.4±7.42 mg vs 161.9±10.82 mg of vehicle-treated control, P 〈 0.05）. Unlike tegaserod, which showed an enhanced water content in fecal pel- lets （59.20%±1.09% vs 51.44%±1.19% of control, P 〈 0.05）, mangiferin evidenced no such effect, indi-cating that it has only a motor and not a secretomotor effect. CONCLUSION： Our data indicate the prokinetic action of mangiferin. It can stimulate the normal GIT and also overcome the drug-induced transit delay, via a choliner- gic physiological mechanism.