Figure 2.
![Figure 2. Decay of the Ca2+ transient is not due to store depletion or to RYR1 inactivation. Representative fluorescence records of WT and Hom R163C myotubes loaded with Fluo-4 AM in response to a 10-s exposure to 20 mM caffeine (Caf) and a 180-s exposure to 60 mM [K+]e, followed by a second 10-s application of 20 mM caffeine (*) applied at different intervals (20–200 s) after the Ca2+ transient was elicited by 60 mM [K+]e. The decay of the Ca2+ transient during K+ depolarization does not appear to be related to SR Ca2+ depletion, nor is it due to RYR1 inactivation based on the amplitude of the second caffeine response (*).](https://cdn.rupress.org/rup/content_public/journal/jgp/135/6/10.1085_jgp.200910328/4/jgp_200910328_rgb_fig2.jpeg?Expires=1773496798&Signature=VqU9EIfgAz89lUz26k6nF~WX14X-CrzL7ITQ2cn7IpDBlbuEqzQXHRob3sQrFiNT3BzfhDNrq2FfwAyN4No8uzTy3rzqOsJ2uHqyvSvLqJIfj60DrVvP3Is4E2OG2Beo1Q6QPLMNnQ2V7Rwf7gTxPcDPbkYeLRTup51gAAeJOEYo5-rD8SfOVLT~FYPsvZ~scd4nxz0wfRKPCxohraN-2rTduNClXUv6qA2TM70yL9Or3wdelHS-KI~KS8xgB0ROz2dbVLrTE-mf9Se~1oYZfGpYuoqMKvEy6sfe7lmqIR7nCXjK~BKdmKCJhn4STcKr5CwKLUsFiVFkxmF3Ah1Q5w__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Decay of the Ca2+ transient is not due to store depletion or to RYR1 inactivation. Representative fluorescence records of WT and Hom R163C myotubes loaded with Fluo-4 AM in response to a 10-s exposure to 20 mM caffeine (Caf) and a 180-s exposure to 60 mM [K+]e, followed by a second 10-s application of 20 mM caffeine (*) applied at different intervals (20–200 s) after the Ca2+ transient was elicited by 60 mM [K+]e. The decay of the Ca2+ transient during K+ depolarization does not appear to be related to SR Ca2+ depletion, nor is it due to RYR1 inactivation based on the amplitude of the second caffeine response (*).
