Korkotian E, Segal M
Department of Neurobiology, The Weizmann Institute, Rehovot, Israel.
Eur J Neurosci. 1998 Jun;10(6):2076-84. doi: 10.1046/j.1460-9568.1998.00219.x.
The emerging significance of calcium stores in neuronal plasticity and the assumed involvement of dendritic spines in long-term plastic properties of neurons have led us to examine the presence and possible regulation of calcium stores in dendritic spines. Immunohistochemical staining for ryanodine receptors was found in dendritic spines of cultured hippocampal neurons. Confocal microscopic imaging of calcium transients in dendritic spines of these neurons in response to caffeine allowed us to demonstrate an independent and unique calcium store in spines. The response to caffeine was blocked by thapsigargin and ryanodine, and maintained in calcium-free medium. The calcium stores were depleted faster in the spines than the dendrites. Furthermore, when calcium was released from stores under calcium-free conditions, and diffused passively between the spine and the dendrite, the length of the spine neck determined the degree of spine independence. Finally, the caffeine-sensitive ryanodine receptor-linked calcium store was instrumental in regulating the response of neurons to glutamate. These results have important implications for understanding the roles of dendritic spines in neuronal integration and plasticity.
钙库在神经元可塑性中日益凸显的重要性以及树突棘被认为参与神经元长期可塑性特性，促使我们研究树突棘中钙库的存在及可能的调控机制。在培养的海马神经元的树突棘中发现了对雷诺丁受体的免疫组织化学染色。对这些神经元的树突棘中钙瞬变对咖啡因的反应进行共聚焦显微镜成像，使我们能够证明树突棘中存在独立且独特的钙库。对咖啡因的反应被毒胡萝卜素和雷诺丁阻断，并在无钙培养基中得以维持。树突棘中的钙库比树突中的消耗得更快。此外，当在无钙条件下从钙库中释放钙并在树突棘和树突之间被动扩散时，树突棘颈部的长度决定了树突棘的独立程度。最后，对咖啡因敏感的与雷诺丁受体相关的钙库有助于调节神经元对谷氨酸的反应。这些结果对于理解树突棘在神经元整合和可塑性中的作用具有重要意义。
