汉防己甲素抑制三种神经递质引起的新生大鼠脑细胞内游离钙的升高

应用Ｐｕｒａ－２技术测定游离新生大鼠脑［Ｃａ２＋］ｉ浓度的技术、研究了Ｔｅｔ对静息脑［Ｃａ２＋］ｉ和３种递质引起的脑［Ｃａ２］ｉ变化的影响。Ｔｅｔ（１，１０和２０μｍｏｌ·Ｌ－１）对静息脑［Ｃａ２＋］ｉ无明显影响。Ｔｅｔ（１０μｍｏｌ·Ｌ－１）可降低Ｌ－Ｇｌｎ（０．１、１．０和１０μｍｏｌ·Ｌ－１）引起的脑（Ｃａ２＋）ｉ的升高。在Ｈａｎｋ＇ｓ液Ｃａ２＋为１．３ｍｍｏｌ·Ｌ－１时，Ｔｅｔ１０μｍｏｌ·Ｌ－１可降低Ｈｉｓ（５０和１００μｍｏｌ·Ｌ－１）和５－ＨＴ（０．１、１．０、１０和１００μｍｏｌ·Ｌ－１）引起的脑［Ｃａ２＋］ｉ的升高。但不能降低Ｈａｎｋ＇ｓ液无Ｃａ２＋时Ｈｉｓ和５－ＨＴ引起的脑［Ｃａ２＋］ｉ的升高。研究表明Ｔｅｔ可阻滞Ｌ－Ｇｉｎ、Ｈｉｓ和５－ＨＴ受体调控的钙通道。但对Ｈｉｓ和５－ＨＴ引起的细胞内贮存钙的释放并无明显影响。Ｔｅｔ的这种降低脑［Ｃａ２＋］ｉ的作用可能是其治疗脑缺血性疾病的机理之一。Ｐ＜０．０１在Ｔｅｔ１０μｍｏｌ·Ｌ－１作用下，相同浓度的细胞外液钙和Ｈｉｓ（０、５０和１００μｍｏｌ·Ｌ－１），脑［Ｃａ２＋］ｉ分别是２２１±５、２４５±５和３０２±６ｎｍｏｌ·Ｌ－１。增加了１１．８?

Tetrandrine inhibits three neurotrasmitters--induced increase of free intracellular Ca in dissociated brain cells from newborn rats

Effects of tetrandrine(Tet)on resting free intracellular Ca level,high potassium depolarization and three neurotrasmitters-induced rise in brainCa2+]i of newborn rats were studied using Fura-2 fluorescence technique.No significant effects of Tet(1,10 and 20 μmol·L-1) on resting brainCa2+]i level were observed.Tet(10μmol·L-1)significantly inhibited Glu(0.1、1.0 and 10 μmol·L-1)-induced increase of brainCa2+]i(P<0. 01), In Hank's solution with 1. 3 mmol·L-1 of Calcium,His(50 and100 μmol·L-1)-and 5-HT(0.1, 1. 0, 10 and 100μmol·L-1)-induced elevations in brain Ca2+]i were reduced by Tet 10 μpol·L-1significantly(P<0.01).But in a free-calcium Hank's solution,Tet did not inhibit Hisand 5-HT-induced rises inCa2+]i.These results suggest that Tet can block L-Gln-,His-and 5-HT-receptoroperated calcium channels,but does not affect His-and 5-HTinduced release of calcium from intracellular store significantly.The action of Tet on BrainCa2+]i may be releated to its protective brain ischemia.