Bilirubin levels in subarachnoid clot and effects on canine arterial smooth muscle cells.
Bilirubin levels in subarachnoid clot and effects on canine arterial smooth muscle cells.
复制标题
蛛网膜下腔凝块中的胆红素水平及其对犬动脉平滑肌细胞的影响。
作者：
Trost,GR;Nagatani,K;Goknur,AB;Haworth,RA;Odell,GB;Duff,TA
以往的研究表明，胆红素是脑血管痉挛的一个潜在因素。本研究的目的是确定是否胆红素积累在蛛网膜下腔凝块，其血管收缩作用是否可能涉及对动脉平滑肌细胞的直接作用，如果是这样，胆红素是否影响其Ca 2 + uptake.Subarachnoid凝块胆红素进行了分析，使用高效液相色谱法。用酶法分离犬颈动脉血管平滑肌细胞，测定胆红素溶液暴露前后平滑肌细胞长度和~（45）Ca ~（2+）摄取量。在培养的犬基底动脉平滑肌细胞和ATP耗竭的心肌细胞上进行了额外的实验，实验凝块中的平均+/- SE胆红素浓度为263 +/- 35.7 mumol/L。暴露于胆红素的血管平滑肌细胞显示进行性缩短（P < .01）和45 Ca 2+摄取增加（P < .001）。无Ca（2+）培养基可阻止收缩，但维拉帕米不能。用心肌细胞进行的实验表明，胆红素引起~（45）Ca ~（2+）摄取增加，但不引起~（14）C蔗糖摄取增加，结果表明胆红素在蛛网膜下腔凝块中积聚，对动脉平滑肌细胞有直接的收缩作用，这种作用与Ca ~（2+）摄取增加有关。对心肌细胞的研究表明，胆红素诱导的Ca 2+摄取可能是由于膜对Ca 2+的通透性选择性增加。
Previous studies have suggested that bilirubin is a potential contributor to cerebral vasospasm. The purpose of this investigation was to determine whether bilirubin accrues in subarachnoid clot, whether its vasoconstrictive effect could involve a direct action on arterial smooth muscle cells, and, if so, whether bilirubin affects their Ca2+ uptake.Subarachnoid clots were analyzed for bilirubin using high-performance liquid chromatography. The length and 45Ca2+ uptake of vascular smooth muscle cells enzymatically dissociated from canine carotid arteries were measured before and after exposure to bilirubin solution. Additional experiments were conducted on cultured smooth muscle cells from canine basilar artery and on ATP-depleted cardiac myocytes.Mean +/- SE bilirubin concentration in experimental clot was 263 +/- 35.7 mumol/L. Vascular smooth muscle cells exposed to bilirubin showed progressive shortening (P < .01) and an increased uptake of 45Ca2+ (P < .001). Contraction was prevented by Ca(2+)-free media but not by verapamil. Experiments with heart myocytes showed that bilirubin caused an increased uptake of 45Ca2+ but not of [14C]sucrose.The results indicate that bilirubin accrues in subarachnoid clot, that it exerts a direct constrictive effect on arterial smooth muscle cells, and that this effect is associated with an increased uptake of Ca2+. Studies on heart myocytes suggest that the Ca2+ uptake induced by bilirubin could be due to a selective increase in membrane permeability to Ca2+.