調(diào)節(jié)鈣離子在胞內(nèi)濃度的緩沖劑
鈣對(duì)于神經(jīng)系統(tǒng)信號(hào)傳遞的重要性眾所周知。例如在樹(shù)突中,鈣進(jìn)入電壓門(mén)控通道后,會(huì)激活許多信號(hào)通路,以行使功能。然而信號(hào)分子并不是當(dāng)鈣離子進(jìn)入神經(jīng)元后與其結(jié)合的唯一蛋白。當(dāng)鈣通道打開(kāi)后,胞內(nèi)的一些緩沖蛋白(buffer)會(huì)與絕大部分進(jìn)入胞內(nèi)的鈣離子結(jié)合,然后,信號(hào)分子再與其競(jìng)爭(zhēng)鈣離子,有關(guān)這些內(nèi)源性buffer的特性還鮮有人知。Lee et al.通過(guò)研究不同類型神經(jīng)元的樹(shù)突對(duì)buffer的均一性進(jìn)行了研究。
Lee et al.利用培養(yǎng)的海馬神經(jīng)元,測(cè)定內(nèi)源性緩沖蛋白對(duì)鈣離子的結(jié)合能力,看看在興奮性神經(jīng)元和抑制性神經(jīng)元中有何區(qū)別。他們發(fā)現(xiàn),興奮性海馬神經(jīng)元內(nèi)源buffer結(jié)合鈣離子的能力遠(yuǎn)低于抑制性神經(jīng)元。興奮性神經(jīng)元中要么缺失要么表達(dá)低水平的鈣離子結(jié)合蛋白,如calbindin
D-28k,而抑制性神經(jīng)元中此類蛋白表達(dá)量都很高,有calretinin,calbindin D-28k和小清蛋白(parvalbumin)。
, 百拇醫(yī)藥
胞內(nèi)鈣的衰減動(dòng)力學(xué)在少數(shù)抑制性神經(jīng)元內(nèi)有反常的行為,表現(xiàn)為一個(gè)快速的初始過(guò)程和緩慢的后期過(guò)程。Lee et al.發(fā)現(xiàn)小清蛋白在樹(shù)突中是一個(gè)緩慢的鈣離子緩沖蛋白,應(yīng)對(duì)緩慢的后期反應(yīng)負(fù)責(zé),他們?cè)谑茹t細(xì)胞中加入了小清蛋白,結(jié)果此類細(xì)胞也表現(xiàn)了這種反常的鈣離子衰減動(dòng)力學(xué)。
Parvalbumin-positive hippocampal neurons in
culture. Photograph courtesy of Dr. Erwin Neher (Max Planck
Institute for Biophysical Chemistry, Gottingen, Germany)
在海馬中小清蛋白陽(yáng)性的神經(jīng)元大部分是抑制性的。小清蛋白的存在即能改變鈣離子濃度衰減的行為,這種緩慢的后期反應(yīng)可能對(duì)延遲樹(shù)突內(nèi)鈣積累有一些作用,而且抑制性神經(jīng)元的軸突內(nèi)是否也有小清蛋白存在,對(duì)鈣離子的積累是否也有同樣的作用呢?
, http://www.www.srpcoatings.com
相關(guān)文章:
Original RESEARCH paper
Lee,S.-H., Rosenmund, C., Schwaller, B. & Neher, E. Differences in
Ca2+ buffering properties between excitatory and inhibitory
hippocampal neurons from the rat. J. Physiol. 525, 405–418 (2000)
Lee,S.-H., Schwaller, B. & Neher, E. Kinetics of Ca2+ binding to
, http://www.www.srpcoatings.com
parvalbumin in bovine chromaffin cells: implications for [Ca2+]
transients of neuronal dendrites. J. Physiol. 525, 419–432 (2000).
[PUBMED] REVIEWS
Baimbridge, K. G., Celio, M. R. & Rogers, J. H. Calcium-binding proteins in
the nervous system. Trends Neurosci. 15, 303–308 (1992).
Neher, E. Usefulness and limitations of linear approximations to the
, 百拇醫(yī)藥
understanding of Ca++ signals. Cell Calcium 24, 345–357 (1998).
Yuste, R., Majewska, A. & Holthoff. K. From form to function: calcium
compartmentalization in dendritic spines. Nature Neurosci. 3,653–659 (2000).
Further READING
Freund,T. F. & Buzsaki, G. Interneurons of the hippocampus. Hippocampus
6, 347–470 (1996).
Naraghi, M., Muller, T. H. & Neher, E. Two-dimensional determination of the Cellular Ca2+ binding in bovine chromaffin cells. Biophys. J. 75,1635–1647 (1998).
新思路
新技術(shù)—其他文章, 百拇醫(yī)藥
Lee et al.利用培養(yǎng)的海馬神經(jīng)元,測(cè)定內(nèi)源性緩沖蛋白對(duì)鈣離子的結(jié)合能力,看看在興奮性神經(jīng)元和抑制性神經(jīng)元中有何區(qū)別。他們發(fā)現(xiàn),興奮性海馬神經(jīng)元內(nèi)源buffer結(jié)合鈣離子的能力遠(yuǎn)低于抑制性神經(jīng)元。興奮性神經(jīng)元中要么缺失要么表達(dá)低水平的鈣離子結(jié)合蛋白,如calbindin
D-28k,而抑制性神經(jīng)元中此類蛋白表達(dá)量都很高,有calretinin,calbindin D-28k和小清蛋白(parvalbumin)。
, 百拇醫(yī)藥
胞內(nèi)鈣的衰減動(dòng)力學(xué)在少數(shù)抑制性神經(jīng)元內(nèi)有反常的行為,表現(xiàn)為一個(gè)快速的初始過(guò)程和緩慢的后期過(guò)程。Lee et al.發(fā)現(xiàn)小清蛋白在樹(shù)突中是一個(gè)緩慢的鈣離子緩沖蛋白,應(yīng)對(duì)緩慢的后期反應(yīng)負(fù)責(zé),他們?cè)谑茹t細(xì)胞中加入了小清蛋白,結(jié)果此類細(xì)胞也表現(xiàn)了這種反常的鈣離子衰減動(dòng)力學(xué)。
Parvalbumin-positive hippocampal neurons in
culture. Photograph courtesy of Dr. Erwin Neher (Max Planck
Institute for Biophysical Chemistry, Gottingen, Germany)
在海馬中小清蛋白陽(yáng)性的神經(jīng)元大部分是抑制性的。小清蛋白的存在即能改變鈣離子濃度衰減的行為,這種緩慢的后期反應(yīng)可能對(duì)延遲樹(shù)突內(nèi)鈣積累有一些作用,而且抑制性神經(jīng)元的軸突內(nèi)是否也有小清蛋白存在,對(duì)鈣離子的積累是否也有同樣的作用呢?
, http://www.www.srpcoatings.com
相關(guān)文章:
Original RESEARCH paper
Lee,S.-H., Rosenmund, C., Schwaller, B. & Neher, E. Differences in
Ca2+ buffering properties between excitatory and inhibitory
hippocampal neurons from the rat. J. Physiol. 525, 405–418 (2000)
Lee,S.-H., Schwaller, B. & Neher, E. Kinetics of Ca2+ binding to
, http://www.www.srpcoatings.com
parvalbumin in bovine chromaffin cells: implications for [Ca2+]
transients of neuronal dendrites. J. Physiol. 525, 419–432 (2000).
[PUBMED] REVIEWS
Baimbridge, K. G., Celio, M. R. & Rogers, J. H. Calcium-binding proteins in
the nervous system. Trends Neurosci. 15, 303–308 (1992).
Neher, E. Usefulness and limitations of linear approximations to the
, 百拇醫(yī)藥
understanding of Ca++ signals. Cell Calcium 24, 345–357 (1998).
Yuste, R., Majewska, A. & Holthoff. K. From form to function: calcium
compartmentalization in dendritic spines. Nature Neurosci. 3,653–659 (2000).
Further READING
Freund,T. F. & Buzsaki, G. Interneurons of the hippocampus. Hippocampus
6, 347–470 (1996).
Naraghi, M., Muller, T. H. & Neher, E. Two-dimensional determination of the Cellular Ca2+ binding in bovine chromaffin cells. Biophys. J. 75,1635–1647 (1998).
新思路
新技術(shù)—其他文章, 百拇醫(yī)藥
百拇醫(yī)藥網(wǎng) http://www.www.srpcoatings.com/Html/Info/News/66/06693.htm