소뇌 Purkinje 세포에서 Na+-Ca2+ 교환 이동의 활성도

초록

Variations in intracellular calcium activity ([Ca2+]i) play crucial roles in information processing in Purkinje neurons. Na+-Ca2+ exchanger (NCX) has been shown to participate in the regulation of Ca2+ homeostasis and secretion in neuronal cells. However, the physiological role of NCX in Purkinje neurons is not well understood. Thus, in this study, we investigated using cellular Ca2+ imaging technique the intracellular Ca2+ metabolism of isolated rat Purkinje neurons and the expression of NCX Purkinje neurons was identified with the immunostaining technique in acutely dissociated rat Purkinje neurons (postnatal 10 days). [Ca2+]i of Purkinje neurons increased with the reverse mode of NCX and decreased with the forward mode. When the cells were pretreated with NCX antisense oligos, [Ca2+]i was not increased with the reverse mode of NCX. And Ca2+ influx due to the reverse mode of NCX was significantly reduced by KB-R7943 and Ca2+ efflux via 0 Ca2+ was inhibited by bepridil. To examine the interaction between NCX and AMPA receptors, AMPA-induced Ca2+ transients were measured with 30 μM bepridil (NCX forward mode inhibitor) or 10 μM KB-R7943 (NCX reverse mode inhibitor) treatments. The AMPA-evoked response was decreased with bepridil or KB-R7943. These results imply that NCX plays an important role in modulating intracelluar Ca2+ activity and interacts with AMPA receptors in acutely dissociated rat Purkinje neurons.