Fig. 6.
Isoflurane increases calcium dependence of transmitter release. (A) Example recording trace in isoCJ1 (blue) and syxH3-C (black) with failures denoted by dashed arrows. (B) Quantification of percentage of failures of evoked response after nerve stimulation in 0.5 mM calcium under isoflurane perfusion in isoCJ1 (blue) and syxH3-C (black). *P < 0.05, t test comparing means. Data in C to F show log–log plots of quantal content with increasing calcium concentrations: 0.5, 0.6, and 0.7 mM. Each point represents the mean ± SEM from more than eight separate recordings per genotype, with data averaged during a 1-min period before and after 6 min of isoflurane perfusion. Lines were fitted with linear regression for each plot. (C) Quantal content–calcium relation for isoCJ1 (blue; slope = 3.31, r = 0.99) and syxH3-C (red; slope = 2.43, r = 0.99) before isoflurane (P = 0.29). (D) Quantal content–calcium relation in isoCJ1 before (blue; slope = 3.31, r = 0.99) and after isoflurane perfusion (green; slope = 7.6, r = 0.99) (P < 0.05). (E) Quantal content–calcium relation in syxH3-C before (red; slope = 2.43, r = 0.99) and after isoflurane perfusion (magenta; slope = 4.4, r = 0.99) (P < 0.05). (F) Quantal content–calcium relation after isoflurane perfusion for isoCJ1 (green; slope = 7.6, r = 0.99) and syxH3-C (magenta; slope = 4.4, r = 0.99) (P < 0.05). *P < 0.05, **P < 0.01, two-way ANOVA with Sidak multiple comparison test.