Hydrogen-Deuterium Exchange Effects on β-Endorphin Release from AtT20 Murine Pituitary Tumor Cells

Masayuki Ikeda, Shigeru Suzuki, Masahiro Kishio, Moritoshi Hirono, Takashi Sugiyama, Junko Matsuura, Teppei Suzuki, Takayuki Sota, Charles N. Allen, Shiro Konishi, Tohru Yoshioka*

*この研究の対応する著者

研究成果: Article査読

6 被引用数 (Scopus)

抄録

Abundant evidences demonstrate that deuterium oxide (D2O) modulates various secretory activities, but specific mechanisms remain unclear. Using AtT20 cells, we examined effects of D2O on physiological processes underlying β-endorphin release. Immunofluorescent confocal microscopy demonstrated that 90% D2O buffer increased the amount of actin filament in cell somas and decreased it in cell processes, whereas β-tubulin was not affected. Ca2+ imaging demonstrated that high-K+-induced Ca2+ influx was not affected during D 2O treatment, but was completely inhibited upon D2O washout. The H2O/D2O replacement in internal solutions of patch electrodes reduced Ca2+ currents evoked by depolarizing voltage steps, whereas additional extracellular H2O/D2O replacement recovered the currents, suggesting that D2O gradient across plasma membrane is critical for Ca2+ channel kinetics. Radioimmunoassay of high-K+-induced β-endorphin release demonstrated an increase during D2O treatment and a decrease upon D2O washout. These results demonstrate that the H 2O-to-D2O-induced increase in β-endorphin release corresponded with the redistribution of actin, and the D2O-to-H 2O-induced decrease in β-endorphin release corresponded with the inhibition of voltage-sensitive Ca2+ channels. The computer modeling suggests that the differences in the zero-point vibrational energy between protonated and deuterated amino acids produce an asymmetric distribution of these amino acids upon D2O washout and this causes the dysfunction of Ca2+ channels.

本文言語English
ページ(範囲)565-575
ページ数11
ジャーナルBiophysical Journal
86
1 I
DOI
出版ステータスPublished - 2004 1

ASJC Scopus subject areas

  • 生物理学

フィンガープリント

「Hydrogen-Deuterium Exchange Effects on β-Endorphin Release from AtT20 Murine Pituitary Tumor Cells」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル