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Ladrat C Chaplet M Verrez-Bagnis V Noël J Fleurence J 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2000,125(1):83-95
Calcium-dependent proteinases or calpains were studied in fish muscle. Hydrophobic chromatography, followed by anion-exchange chromatography of the soluble fraction of sea bass white muscle proteins, resulted in three peaks of calcium-dependent protease activity at neutral pH (A, B and C). They are all neutral cysteine calcium-activated proteinases and can, therefore, be classified as calpain-like enzymes. From the Ca2+ concentration required for activity, A is a mu-calpain, and B and C are m-calpains. They share many properties with calpains from other vertebrate cells but differ in native mass, subunit composition, and the unusual numbers in which they are present. Their specific pattern of expression throughout the year could be of great importance to the resulting rate and extent of degradation of fish flesh after death. 相似文献
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Aksulu HE Bingöl I Karatas F Sagmanligil H Ustündag B 《Physiological research / Academia Scientiarum Bohemoslovaca》2000,49(1):175-182
In this study, we investigated the effects of N(omega)-nitro-L-arginine (L-NNA) on arterial blood pressure (BP), plasma noradrenaline (NA) and adrenaline (A) levels and angiotensin-converting enzyme (ACE) activity. L-NNA was applied with tap water (1 mg/ml) from the 3rd to the 8th week of age (group L-NNA1). In Experiment 1, long-term L-NNA application increased BP compared to the control group (group C1) (L-NNA1 = 131.4 +/- 6.3, n = 6; C1 = 82.7 +/- 4.7 mm Hg, n = 7) but decreased plasma noradrenaline and adrenaline levels and ACE activity (NA levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 8.6 +/- 0.5 ng/ml, n = 7; A levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 6.0 +/- 0.5 ng/ml, n = 7; ACE activities: C1 = 87.3 +/- 3.1, n = 6; L-NNA1 = 46.2 +/- 1.9 U/l, n = 5). On the other hand, in Experiment 2 (carried out under the same conditions and in age-matched chickens), blood pressure, plasma noradrenaline levels and ACE activity were found to differ in the control group (C2) (BP = 141.4 +/- 15.5 mm Hg, n = 7; NA = 1.1 +/- 0.4 ng/ml, n = 7; ACE = 57.2 +/- 5.3 U/l, n = 7) as compared to C1, while plasma adrenaline levels were similar. In this series, long-term L-NNA application (group L-NNA2) did not change the BP, but surprisingly increased noradrenaline and ACE values (values of L-NNA2: BP = 165.7 +/- 15.6 mm Hg, n = 7; NA = 9.3 +/- 1.3 ng/ml, n = 8; ACE = 149.4 +/- 16 U/l, n = 8) while decreasing plasma adrenaline levels. L-arginine addition to L-NNA treatment completely reversed plasma noradrenaline and ACE activity values. These results indicate the modulatory activity of an L-arginine-NO pathway on adrenaline release as well as on the renin-angiotensin system in chickens. 相似文献
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Evaluation of endothelium-protective effects of drugs in experimental models of endothelial damage 总被引:1,自引:0,他引:1
Kristová V Kriska M Babál P Djibril MN Slámová J Kurtansky A 《Physiological research / Academia Scientiarum Bohemoslovaca》2000,49(1):123-128
Endothelium-protective properties of pharmacological agents may be assessed by using different experimental models of endothelial dysfunction or injury. The model of endothelial dysfunction induced by vessel perfusion with polymorphonuclear leukocytes (PMN) was used for evaluation of pentoxifylline (PTX) effects on vasoconstrictor responses to noradrenaline (NA) in the rabbit renal artery. Addition of PMN into the perfusion solution significantly increased the responses to NA at all doses. PTX administration (10(-5) mol x l(-1)) significantly diminished the constrictor responses to NA in vessels perfused with PMN+PTX when compared to the responses in PMN-perfused vessels (at dose 0.1 microg: 32.25 vs. 14.25, at dose 1 microg: 51 vs. 27.75 (p<0.01), at dose 10 microg 74.25 vs. 39.75 (p<0.05), all values expressed as median of perfusion pressure in mm Hg). The model of endothelial damage induced by repeated NA administration in 5 doses (10-50 microg of NA) was used for evaluation of the endothelium-protective effect of sulodexide (SLX). It was found that SLX (120 U/l) significantly decreased the number of desquamated endothelial cells (EC) compared to the control group (controls: 131.4+/-20.1 EC, +SLX: 83.3+/-13.8 EC, p<0.01). These results confirmed the favorable endothelium-protective effects of pentoxifylline and sulodexide in the two experimental models. 相似文献
959.
Le Dréan G Le Huërou-Luron I Gestin M Romé V Bernard C Chayvialle JA Fourmy D Guilloteau P 《Canadian journal of physiology and pharmacology》2000,78(10):813-819
In bovine species, as in human, the pancreas predominantly expresses cholecystokinin-B (CCK-B)/gastrin receptors. However, the role of this receptor in the regulation of meal-stimulated pancreatic enzyme release has not been determined. In milk-fed calves, we previously described prandial patterns of exocrine pancreatic secretion and a long prefeeding phase was observed. The present study was aimed at determining both the role of external stimuli in the outset of the prefeeding phase and the implication of pancreatic CCK-A and CCK-B/gastrin receptors in the mediation of pancreatic response to feeding. The first objective was studied by suppressing external stimuli associated with food intake (unexpected meal) and the second by infusing highly specific and potent antagonists of CCK-A (SR 27897) and CCK-B/gastrin (PD 135158) receptors during the prandial period. When calves were given an unexpected meal, the long prefeeding increase in pancreatic secretion was absent. SR 27897 (but not PD 135158) inhibited the preprandial phase and greatly reduced postprandial pancreatic juice and enzyme outflows. The expectancy of a meal seemed to elicit an increased pancreatic response right before a meal and CCK-A receptors may mediate this information via neural pathways. The implication of CCK and CCK-A receptors in mediating the postfeeding pancreatic response was also demonstrated. The participation of CCK-B/gastrin receptors in this regulation was not demonstrated. 相似文献
960.
Loreau O Maret A Poullain D Chardigny JM Sébédio JL Beaufrère B Noël JP 《Chemistry and physics of lipids》2000,106(1):65-78
Several grams of labelled trans linoleic and linolenic acids with high chemical and isomeric purities (>97%) have been prepared for human metabolism studies. A total of 12.5 g of (9Z, 12E)-[1-(13)C]-octadeca-9,12-dienoic acid and 6.3 g of (9Z,12Z, 15E)-[1-(13)C]-octadeca-9,12,15-trienoic acid were obtained in, respectively, seven steps (7.8% overall yield) and 11 steps (7% overall yield) from 7-bromo-heptan-1-ol. The trans bromo precursors used for the labelling were synthesised by using copper-catalysed couplings. The trans fatty acids were then obtained via the nitrile derivatives. A total of 23.5 g of (9Z,12Z)-[1-(13)C]-octadeca-9, 12-dienoic acid and 10.4 g of (9Z,12Z,15Z)-[1-(13)C]-octadeca-9,12, 15-trienoic acid were prepared in five steps in, respectively, 32 and 18% overall yield. Large quantities of bromo and chloro precursors were synthesised from the commercially available acid according to Barton's procedure. In all cases, the main impurities (>0.5%) of each labelled fatty acid have been characterised. 相似文献