A highly sensitive fluorescent indicator dye for calcium imaging of neural activity in vitro and in vivo.
Bottom Line: Therefore, it is difficult to detect signals caused by single action potentials (APs) particularly from neurons in vivo.Here we showed that a recently developed calcium indicator dye, Cal-520, is sufficiently sensitive to reliably detect single APs both in vitro and in vivo.These characteristics of Cal-520 are a great advantage over those of Oregon Green BAPTA-1, the most commonly used calcium indicator dye, for monitoring the activity of individual neurons both in vitro and in vivo.
Affiliation: Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.Show MeSH
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Mentions: To quantitatively compare the signal amplitude and SNR, we next performed high-speed linescan imaging (sampling rate, 500 Hz) (Fig.4A and B). The mean amplitude of individual calcium transients using Cal-520 was significantly larger than that using OGB-1 (0.696 ± 0.010 and 0.434 ± 0.011 ΔF/F, 49 cells in nine mice and 14 cells in four mice, respectively, P=0.02, Mann–Whitney U-test) (Fig.4C), which resulted in higher SNRs (5.390 ± 0.052 for Cal-520 and 3.465 ± 0.077 for OGB-1, P=0.0004) (Fig.4D). The kinetic properties of calcium transients were not different between Cal-520 and OGB-1 [10–90 rise time (Fig.4E): 0.053 ± 0.001 and 0.099 ± 0.006 s, 49 cells in nine mice and 14 cells in four mice, respectively, P=0.09; decay time constants by double-exponential fitting (Fig.4F): 0.755 ± 0.009 and 1.055 ± 0.010 s for Cal-520 (46 cells in nine mice), 0.675 ± 0.037 and 1.196 ± 0.043 s for OGB-1 (12 cells in four mice), P=0.60 and 0.28, respectively].
Affiliation: Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.