Effects of gingko biloba extract on glutamate-induced Ca2+i changes in cultured cortical astrocytes after hypoxia/reoxygenation, H2O2 or L-glutamate injury / 药学学报

<p><b>AIM</b>To investigate glutamate-induced [Ca2+]i changes in cultured rat neonatal cortical astrocytes after hypoxia/reoxygenation, H2O2 or high concentration of L-glutamate injury. In the meantime, the effects of Gingko biloba extract (GbE) were examined.</p><p><b>METHODS</b>[Ca2+]i changes in astrocytes were monitored by laser scanning confocal microscopy with the Ca2+ sensitive fluorescent probe fluo-3.</p><p><b>RESULTS</b>After astrocytes were impaired by hypoxia/reoxygenation, H2O2 (50 micromol x L(-1)) or L-glutamate (0.25 mmol x L(-)), the exogenous glutamate (27 micromol x L(-1)) could not induce increase of [Ca2+]i, but decrease by (3.3 +/- 1.6)%, (81 +/- 11)% and (81 +/- 7)%, respectively. Pretreatment with GbE (10 mg x L(-1)) could not improve injured astrocytic glutamate response. But after pretreatment with GbE (100 mg x L(-1)), glutamate-induced [Ca2+]i elevation of astrocytes after hypoxia/reoxygenation, H2O2 or high concentration of L-glutamate injury were (135 +/- 98)%, (117 +/- 93)% and (89 +/- 36)%, respectively. Nimodipine (1.6 mg x L(-1)) could also reverse the abnormal response of astrocytes after different injury.</p><p><b>CONCLUSION</b>Hypoxia/reoxygenation, H2O2 and high concentration of L-glutamate impaired astrocytes' response to exogenous L-glutamate, and then bidirectional communication between astrocytes and neurons could not take place. GbE could improve the abnormal responses and maintain the normal function of astroglical network. These effects support that GbE has potential beneficial actions against brain injury.</p>

Effect of phenolic alkaloids of Menispermum dauricum on thrombosis and platelet aggregation / 药学学报

<p><b>AIM</b>To observe the effect of phenolic alkaloids of Menispermum dauricum (PAMD) on thrombosis and platelet aggregation, and to explore its mechanism of action.</p><p><b>METHODS</b>Thrombosis was observed with arteriovenous shunt thrombus model in rat; platelet aggregation was determined by Born's method; ultrastructure of platelet was observed by transmission electron microscope; TXB2 or 6-keto-PGF1alpha levels were assessed by radioimmunoassay; and NO was determined by colorimetric method.</p><p><b>RESULTS</b>PAMD dose-dependently inhibited experimental thrombus formation, platelet aggregation induced by ADP, AA and THR in vivo and ultrastructure changes stimulated by THR; PAMD increased the generation of 6-keto-PGF1alpha in thoracic aortae and NO level in plasma; and had no influence on TXB2 release (P > 0.05).</p><p><b>CONCLUSION</b>PAMD inhibited thrombosis and platelet aggregation, and its mechanism might be due to the increase of PGI2 and NO level.</p>

Protective effect of procyanidins from the seedpod of the lotus on myocardial ischemia and reperfusion injury in rat / 药学学报

<p><b>AIM</b>To study the protective effect of procyanidins from the seedpod of the lotus (LSPC) on myocardial ischemia and reperfusion in rats.</p><p><b>METHODS</b>Myocardial injury model was made by ligating the coronary artery for 30 min followed by reperfusion for 45 min in anesthetized rat and 30 min of ischemia followed by 30 min of reperfusion in the isolated rat heart. All animals were given the medicine or normal saline before the experiment. ET, Ang I, Ang II in the serum, the MDA content, SOD activity, NO level, the recovery rate of coronary flow (CF) and heart rate (HR) after reperfusion and CK, XO from the myocardial cells were observed.</p><p><b>RESULTS</b>LSPC was shown to inhibit the release of ET, Ang II (P < 0.05) , and the increase of MDA content (P < 0.05). It was also found to increase the SOD activity (P < 0.05) and NO level (P < 0.01). LSPC was found to increase the recovery rate of the coronary flow (CF) and heart rate (HR) after reperfusion (P < 0.05 or P < 0.01), decrease the release of CK from the myocardial cells (P < 0.01), depress the XO activity of myocardial tissue (P < 0.05), as well as improve the myocyte ultrastructural pathological injury.</p><p><b>CONCLUSION</b>The anti-ischemia effect of LSPC was related to the mechanism of scavenging the oxygen free radicals directly, cutting off the source of free radicals, reducing tissue peroxidation, stabilizing the cells membrane, depressing the production of EDCF and increasing the NO level as well.</p>

Effects of phenolic alkaloids of Menispermum dauricum on the hemodynamics and coronary circulation in anesthetized dog / 药学学报

<p><b>AIM</b>To observe the effect of phenolic alkaloids of Menispermum dauricum (PAMD) on the hemodynamics, coronary circulation and oxygen metabolism of the myocardium in anesthetized dogs.</p><p><b>METHODS</b>In this study, the changes of LVSP, LVEDP and +/- dp/dtmax, the flow of coronary artery and myocardial energy metabolism were measured in anesthetized dog with PAMD or NS.</p><p><b>RESULTS</b>In the anesthetized dogs, compared with pre-treatment status, PAMD at 3.5 and 7.0 mg.kg-1 caused decreases in the left ventricular systolic pressure(LVSP), +/- dp/dtmax, heart rate, the rate of oxygen utilization, the coronary and general peripheral resistance. It was found to increase myocardial oxygen and coronary flow. There were no significant change in the left ventricular end diastolic pressure (LVEDP).</p><p><b>CONCLUSION</b>PAMD can ameliorate hemodynamics, coronary circulation and myocardial metabolism.</p>