Department of Neurobiology and Behavior, University of California, Irvine, California, USA.
Biophys J. 2013 Jan 22;104(2):386-95. doi: 10.1016/j.bpj.2012.12.024.
We examined the effect of temperature (12-40°C) on local and global Ca2+ signals mediated by inositol trisphosphate receptor/channels (IP3R) in human neuroblastoma (SH-SY5Y) cells. The amplitudes and spatial spread of local signals arising from single IP3R (blips) and clusters of IP3R (puffs) showed little temperature dependence, whereas their kinetics (durations and latencies) were markedly accelerated by increasing temperature. In contrast, the amplitude of global Ca2+ waves increased appreciably at lower temperatures, probably as a result of the longer duration of IP(3)R channel opening. Several parameters, including puff and blip durations, puff latency and frequency, and frequency of repetitive Ca2+ waves, showed a biphasic temperature dependence on Arrhenius plots. In all cases the transition temperature occurred at ∼25°C, possibly reflecting a phase transition in the lipids of the endoplasmic reticulum membrane. Although the IP3-evoked Ca2+ signals were qualitatively similar at 25°C and 36°C, one should consider the temperature sensitivity of IP3-mediated signal amplitudes when extrapolating from room temperature to physiological temperature. Conversely, further cooling may be advantageous to improve the optical resolution of channel gating kinetics.
我们研究了温度（12-40°C）对人神经母细胞瘤（SH-SY5Y）细胞中肌醇三磷酸受体/通道（IP3R）介导的局部和全局 Ca2+信号的影响。单个 IP3R（闪烁）和 IP3R 簇（脉冲）产生的局部信号的幅度和空间传播几乎不受温度影响，而其动力学（持续时间和潜伏期）随着温度升高而明显加快。相比之下，全局 Ca2+波的幅度在较低温度下显著增加，可能是由于 IP(3)R 通道开放的持续时间更长所致。几个参数，包括脉冲和闪烁的持续时间、脉冲潜伏期和频率以及重复 Ca2+波的频率，在 Arrhenius 图上表现出双相温度依赖性。在所有情况下，转换温度都发生在约 25°C，可能反映了内质网膜脂质的相变。尽管在 25°C 和 36°C 时 IP3 诱导的 Ca2+信号在质量上相似，但在从室温外推到生理温度时，应考虑 IP3 介导的信号幅度的温度敏感性。相反，进一步冷却可能有利于提高通道门控动力学的光学分辨率。
