Objective To study the central role of ginkgolide B （BN52021） in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus ...Objective To study the central role of ginkgolide B （BN52021） in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus （PVN） neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results （1） In response to the application of ginkgolide t3 （0.1, 1, 10 μmol/L; n = 27） into the perfusate for 2 rain, the spontaneous discharge rates （SDR） of 26 （26/27, 96.30%） neurons were significantly decreased in a dose-dependent manner. （2） Pretreatment with L-glutamate （L-Glu, 0.2 mmol/L） led to a marked increase in the SDR of all 8 （100%） neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B （1 μmol/L） was applied into the perfusate for 2 min. （3） In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 （0.1 μmol/L）, induced a significant increase in the discharge rates of 8 （8/8, 100%） neurons, while ginkgolide B （1μmol/L） applied into the perfusate, could inhibit the discharges of 8 （100%） neurons. （4） In 8 neurons, the broad potassium channels blocker, tetraethylammonium （TEA, 1 mmol/L） completely blocked the inhibitory effect of ginkgolide B （1 μmol/L）. Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel （KDR）.展开更多
The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DP...The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.展开更多
文摘Objective To study the central role of ginkgolide B （BN52021） in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus （PVN） neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results （1） In response to the application of ginkgolide t3 （0.1, 1, 10 μmol/L; n = 27） into the perfusate for 2 rain, the spontaneous discharge rates （SDR） of 26 （26/27, 96.30%） neurons were significantly decreased in a dose-dependent manner. （2） Pretreatment with L-glutamate （L-Glu, 0.2 mmol/L） led to a marked increase in the SDR of all 8 （100%） neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B （1 μmol/L） was applied into the perfusate for 2 min. （3） In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 （0.1 μmol/L）, induced a significant increase in the discharge rates of 8 （8/8, 100%） neurons, while ginkgolide B （1μmol/L） applied into the perfusate, could inhibit the discharges of 8 （100%） neurons. （4） In 8 neurons, the broad potassium channels blocker, tetraethylammonium （TEA, 1 mmol/L） completely blocked the inhibitory effect of ginkgolide B （1 μmol/L）. Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel （KDR）.
文摘The effects of urinary macromolecul e chondroitin sulfate A(C 4 S)and L-glutamic acid(L-Glu)on the crys-tallization of calcium oxalate were studied using Langmuir-Blodgett(LB)film of dipalmitoylphosphatidylch oline(DPPC)as templet.All the calcium oxalate c rystals induced by the LB film of DPPC were calcium oxalate monohydrate(COM).However,the morphology of COM was i nfluenced by the additives of C 4 S and L-Glu.C 4 S induced thin and long hexagonal COM c rystals;L-Glu made one or two (010)crystal face of COM crystals dis-appeared.The crystallization time had no effect on the morphology of COM crystals,but the concentration of C 4 S and L-Glu changed it.As increasing the co ncentration of C 4 S,the amount of COM crystals with a hexagonal prism decreased and that with a thin hexago nal slice increased.When the concen tration of C 4 S was 0.50mg ·mL -1 ,all the calcium oxalate crystals were th in hexagonal slice COM crystals.How ever,as the concentration of L-Glu in-creased from 0.01to 0.50mmol·L -1 ,the hexagonal prism-like COM crystals gradually transformed to COM crystals with one or two (010)crystal face disappearance.
