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As deficiencies of the cholinergic and non-adrenergic non-cholinergic innervation of the gastrointestinal tract have been described in diabetic rats, we studied the simultaneous release of, and muscular response to, acetylcholine, vasoactive intestinal polypeptide and adenosine-5'-triphosphate in isolated preparations of gastric fundus from control and 8-week streptozotocin-treated diabetic rats. Muscular responses were measured in longitudinal muscle strips prepared from one half of the gastric fundus and release was studied in the other half. The contractile response to acetylcholine and electrical field stimulation was not different in control and diabetic rats. In the presence of atropine, and when tone was increased with prostaglandin F2 alpha, electrical field stimulation, vasoactive intestinal polypeptide and adenosine-5'-triphosphate induced relaxation with a similar response in control and diabetic rats. The basal release of acetylcholine, vasoactive intestinal polypeptide and adenosine-5'-triphosphate was not significantly different in control and diabetic rats. Electrical field stimulation significantly increased the release of the three substances and this increase was tetrodotoxin-sensitive. While the stimulation-induced increase of acetylcholine and vasoactive intestinal polypeptide was not different in control and in diabetic rats, the stimulation-induced release of adenosine-5'-triphosphate increased 3-fold in diabetic compared to control gastric fundus. Desensitization to alpha,beta-methylene adenosine-5'-triphosphate reduced the relaxant response to adenosine-5'-triphosphate and to electrical field stimulation, suggesting a role of adenosine-5'-triphosphate in non-adrenergic non-cholinergic neurotransmission of rat gastric fundus. The reduction of the non-adrenergic non-cholinergic relaxation by alpha,beta-methylene adenosine-5'-triphosphate was greater in diabetic tissues. This, with the increase in stimulation-induced adenosine-5'-triphosphate release, suggests that the purinergic component of the vagal non-adrenergic non-cholinergic response of the stomach may be increased in diabetics. 相似文献
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Yannick Marchand Celeste D Lefebvre John F Connolly 《International journal of psychophysiology》2006,62(2):280-289
Event-related brain potentials (ERPs) were recorded during a computerized and modified version of the Digit Span Backwards (DB) task from the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). The modified DB version (ERP-DB task) was divided into two sections of 2, 4, 6 and 8 digits in length (Group 1) and 3, 5 and 7 digits in length (Group 2). Each trial had a study phase and a test phase. For the study phase, a series of digits was presented sequentially and aurally to 20 participants (10 for each group). For the test phase, a second series of digits was also presented sequentially and aurally that either corresponded to the reverse order of the digits in the study phase (correct condition) or had one digit in the sequence replaced by an incorrect digit (incorrect condition). The traditional DB task of the WAIS-III was also administered for comparison purposes. A prolonged positive slow wave (PSW) peaking between 450 and 750 ms was elicited to incorrect condition trials. For each participant, a derived measure was calculated from the ERP differentiation between correct and incorrect conditions. The derived measure was defined as the mean of the t-values obtained from the correct and incorrect waveform comparison, within the temporal interval that encompassed this component. The strongest statistical correlations between the derived measure and the traditional DB test scores were found at the Pz site (Group 1: r=0.79; Group 2: r=0.59). This statistical approach shows that it is possible to adequately relate an individual's performance on a traditional measure of working memory and ERP patterns. Overall, we believe that this kind of ERP approach holds promise as a technique for assessing quantitatively non-communicative patients. 相似文献
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Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
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表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献