The expression of the calcium binding protein calretinin in the rat striatum: effects of dopamine depletion and L-DOPA treatment

The activity of the striatum is regulated by glutamate and dopamine neurotransmission. Consequent to striatal dopamine depletion the corticostriatal excitatory input is increased, which in turn can raise intracellular calcium levels. We investigated changes in the neuronal expression of the calcium binding protein calretinin related to dopamine depletion and l-DOPA administration. Immunohistochemical methods were used to assess calretinin in the striatum of rats with unilateral lesions of the nigrostriatal system. In these animals we observed a loss of the patchy distribution of calretinin fibers. Moreover, after dopaminergic depletion we detected two new, not previously described, calretinin cell types, the presence of which could be related to morphological changes induced by loss of a dopaminergic input. We also found an increase in the number of calretinin-labeled cells in the striatum ipsilateral to the lesion compared to the contralateral striatum or to the striatum of normal rats. This increase was mostly evident at 3 weeks postlesion and tended to decrease toward normal levels at 6, 10, and 18 weeks postlesion. In unlesioned animals, l-DOPA administration did not induce changes in the expression of calretinin. In unilaterally lesioned animals, l-DOPA reversed the increase in the number of calretinin-positive cells induced by the lesion. However, chronic l-DOPA administration was less effective than acute l-DOPA in reversing the effect of the lesion. The present data suggests that striatal calretinin neurons are sensitive to dopamine depletion. Increased expression of calretinin in striatal cells may be consequent to enhanced striatal excitatory input.     

Coronary and systemic hemodynamic effects of clevidipine, an ultra-short-acting calcium antagonist, for treatment of hypertension after coronary artery surgery

BACKGROUND: The aim was to evaluate the use of clevidipine, a new vascular selective, ultra-short-acting calcium antagonist for blood pressure control after coronary artery bypass grafting (CABG). METHODS: The effects of clevidipine on central hemodynamics, myocardial blood flow and metabolism were studied at two different phases after CABG. In phase 1 (n=13), the hypertensive phase, the effects of clevidipine were compared to those of sodium nitroprusside (SNP) when used to control postoperative hypertension. In phase 2 (n=9), the normotensive phase, a clevidipine dose-response relationship was established. RESULTS: At a target mean arterial pressure (MAP) of 75 mmHg, systemic vascular resistance (SVR) and heart rate (HR) were lower, preload, stroke volume (SV) and pulmonary vascular resistance (PVR) were higher, while there were no differences in myocardial lactate metabolism or oxygen extraction with clevidipine compared to SNP. In the normotensive phase, clevidipine induced a dose-dependent decrease in MAP (-19%), SVR (-27%) and PVR (-15%), accompanied by an increase in SV (10%), but no reflex increase in HR or changes in cardiac preload. Clevidipine caused a direct coronary vasodilation, as indicated by a decrease in myocardial oxygen extraction from 54% to 45%. Myocardial lactate metabolism was unaffected by clevidipine. The blood clearance of clevidipine was 0.05 l x min(-1) x kg(-1), the volume of distribution at steady state was 0.08 l x kg(-1) and the initial and terminal half-lives were <1 min and 4 min, respectively. CONCLUSIONS: Clevidipine rapidly reduced MAP and induced a systemic, pulmonary and coronary vasodilation with no effect on venous capacitance vessels or HR. Clevidipine caused no adverse effects on myocardial lactate metabolism. Clevidipine thus appears suitable to control blood pressure after CABG.     

参麦注射液与氨茶碱对膈肌细胞Ca2+浓度的影响

目的 :探讨参麦注射液与氨茶碱对膈肌细胞内游离Ca2 浓度的影响。方法 :体外培养大鼠膈肌细胞 ,荧光光度法测定参麦注射液与氨茶碱处理前后细胞内Ca2 浓度的变化。结果 :氨茶碱可使膈肌细胞内的Ca2 浓度明显升高(P<0.01) ,维拉帕米或预先去除培养液中Ca2 可消除该作用。参麦注射液对膈肌细胞内Ca2 浓度无明显影响(P>0.05)。缺氧24h即可致膈肌细胞内Ca2 浓度明显升高(P<0.01) ,参麦注射液对缺氧24h所致的膈肌细胞内Ca2 浓度升高有抑制作用。结论 :细胞外Ca2 是氨茶碱导致细胞内Ca2 升高的关键因素 ,氨茶碱可通过促进细胞外Ca2 内流导致细胞内Ca2 升高。参麦注射液可抑制缺氧所致的膈肌细胞内Ca2 超载 ,对细胞有一定的保护作用。以上作用分别参与了二者抗膈肌疲劳的机制     

铅对小鼠海马[Ca2+]的影响及L型钙通道的作用

目的　探讨铅对分离的小鼠海马细胞内游离钙的影响及其及L型钙通道的作用。方法　采用低浓度胰蛋白酶消化法分离小鼠海马细胞 ,并以莹光指标剂 (Fura 2 )作Ca2 荧光探针 ,用双波长荧光法测定海马细胞 [Ca2 ] i。结果　铅可致分离的小鼠海马细胞 [Ca2 ] i 升高 [由静息时的 (2 0 3 4± 10 86)nmol L升至 (4 2 3 3± 19 2 6)nmol L] ,而不论胞外是否有钙 ;铅可抑制钾诱发海马细胞 [Ca2 ] i 升高 ,尼莫地平可加强这种抑制作用 ,而BayK864 4则可部分消除这种抑制作用。结论　铅可致分离的小鼠海马细胞 [Ca2 ] i 升高作用与胞内钙库释放有关 ;铅的抑制钾诱发海马细胞 [Ca2 ] i 升高作用与其抑制L型钙通道有关。     

钙和维生素D补充剂对结直肠肿瘤的预防效应

对近年来结直肠癌的病因学研究及钙和维生素D作为其潜在的化学性预防剂的干预研究资料加以综述，并提出需进一步研究的方向。     

(S)-(—)-氨氯地平苯磺酸盐二水合物的制备

氨氯地平消旋体经D-(—)-酒石酸拆分,得到(S)-(—)-氨氯地平,再与苯磺酸成盐制得钙通道阻滞剂(S)-(—)-氨氯地平苯磺酸盐二水合物,收率67%,光学纯度近100%.     

两种药物治疗糖尿病视网膜病变的成本-效果分析

目的 :研究进口与国产羟苯磺酸钙治疗糖尿病视网膜病变的成本 -效果。方法 :采用疗效观察和成本 -效果分析方法对进口与国产羟苯磺酸钙进行经济学评价。结果与结论 :进口与国产羟基磺酸钙治疗糖尿病视网膜病变的效果相近 ,但国产品是更经济的选择。     

青少年膳食钙摄入状况对骨密度的影响

目的了解青少年膳食钙摄入状况及骨量水平。方法对昆明市98名12～14岁青少年问卷调查了解膳食营养状况,特别是每日摄入牛奶量的情况,使用双能X线骨密度测定仪(DEXA)测量腰椎及髋部骨密度(BMD)。结果每日坚持喝牛奶的学生骨密度显著高于不喝牛奶的学生。结论膳食中牛奶是影响青少年骨量水平的主要因素。     

应用脱钙骨基质和硫酸钙颗粒治疗骨缺损的初期结果

目的探讨使用骨移植替代物脱钙骨基质（DBM）和硫酸钙颗粒（OSTEOSET）治疗骨缺损的疗效。方法对同期手术治疗的52例骨缺损患者的缺损处,分别于术后第1、4、8周及3、6、12个月进行随访并摄X线片直至骨缺损愈合。统计分析患者的临床资料、X线片辅助分析骨缺损修复程度和并发症。结果随访8-12个月,植骨术后6、12个月分别有95%和99%患者的骨缺损显示有明显的新骨形成,修复水平为60%-100%。并发症为3例（5.77%）,经换药后治愈,未发生骨缺损不愈合。结论DBM和OSTEOSET在骨愈合早期可加速骨缺损的修复,并可作为新鲜自体髂骨的替代物。     

缬沙坦对大鼠心室肌细胞L-型钙通道电流的影响

目的研究AT1受体拮抗剂缬沙坦对正常大鼠心室肌细胞L-钙电流(Ica-L)的影响。方法采用全细胞膜片钳技术,观察0.4μmol/L的缬沙坦引起单个大鼠心室肌细胞L型钙通道电流变化。结果0.4μmol/L缬沙坦使正常大鼠心室肌细胞L型钙电流峰值明显降低(P<0.01),I-V曲线上移,但不改变其激活电位、峰值电位和反转电位。不影响通道稳态激活曲线,使稳态失活曲线左移。结论0.4μmol/L缬沙坦可直接阻断大鼠心室肌细胞L型钙通道,改变心室肌细胞的电生理特性,可能是其抗心律失常的机制之一。