Figure 5.
Smaller subsynaptic IP
3
-releasable [Ca
2+
]
i
pool in in vitro denervated FDB adult skeletal muscle fibers.
(A) On the left, mean traces of subsynaptic [Ca2+]i increases measured in innervated (24 h after plating; n = 44 endplates) and in in vitro denervated FDB adult skeletal muscle fibers (7 d in culture; n = 29 endplates). Trace interruption marks the time of flash photolysis of caged IP3 (Flash). Inset: Mean trace of fluorescence measured after the UV flash in the absence of caged IP3. On the right, the scatter plot of the normalized peak values of the [Ca2+]i increases measured in in vitro denervated versus innervated fibers after flash photolysis. White and grey boxes represent the mean peak values ± SEM. *, P < 0.0001, Mann–Whitney test. (B) On the left, mean traces of subsynaptic [Ca2+]i increases after 20 μM CPA addition upon basal [Ca2+]i recovery from photolysis. On the right, scatter plot of the normalized area values of the [Ca2+]i changes induced by CPA application (3.5 min) in in vitro denervated versus innervated fibers. White and grey boxes represent the mean area values ± SEM. *, P = 0.0037, Mann–Whitney test.