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. 2004 Aug 4;24(31):6871–6879. doi: 10.1523/JNEUROSCI.1538-04.2004

Figure 3.

Figure 3.

Decreased quantal size and normal homeostatic compensation at Pak mutant NMJ. A, Quantification of quantal size in control (filled bar) and experimental genotypes (open bars). Wild-type and heterozygous controls [Df(3R)Win11/+ and Pak6/+; GluRIIASP16/+] have quantal sizes equal to 1.1 ± 0.1 mV (n = 6), 0.98 ± 0.7 mV (n = 6), and 0.96 ± 0.83 mV (n = 5), respectively. Experimental genotypes all showed significant decreases in quantal size: Pak6/Df(3R)Win11, 0.73 ± 0.07 mV, n = 6; GluRIIASP16, 0.51 ± 0.01 mV, n = 18; GluRIIASP16; Pak6/+, 0.46 ± 0.02 mV, n = 5; GluRIIASP16; Pak3/Pak6, 0.4 ± 0.01, n = 7. There is also a small, yet statistically significant, difference between GluRIIASP16 and GluRIIASP16; Pak3/Pak6. B, Quantification of quantal content in control (filled bars) and experimental genotypes (open bars). There is no difference in quantal content comparing the experimental genotype Pak6/Df(3R) Win11 with wildtype or experimental controls. Values are as follows: wildtype, 34.5 ± 1.5, n = 6; Df(3R)Win11/+, 32.1 ± 2.8, n = 6; Pak6/+; GluRIIASP16/+, 39.3 ± 5.2, n = 5; Pak6/Df(3R)Win11, 40.7 ± 3.7, n = 6. The experimental genotypes GluRIIASP16, GluRIIASP16; Pak6/+, and GluRIIASP16; Pak3/Pak6 all showed significant increases in quantal content compared with wild type and genetic controls, indicating that homeostatic compensation has occurred. Values are as follows: GluRIIASP16, 58 ± 3.7 mV, n = 15; GluRIIASP16; Pak6/+, 48.8 ± 5.2 mV, n = 5; and GluRIIASP16; Pak3/Pak6, 63.6 ± 8.7, n = 6. C, Representative traces of evoked potentials (left; each trace represents the average of 10 individual traces) and spontaneous miniature potentials (right) from control [Df(3R)Win11/+] and Pak mutant NMJ [Pak6/Df(3R)Win11]. The traces show the reduction in quantal size in Pak mutant animals and the wild-type EPSP amplitude indicative of effective synaptic homeostasis. Calibration: 10 mV, 50 msec (for evoked release); 1 mV, 250 msec (for spontaneous traces). Significance is denoted as *p < 0.05; **p < 0.002; ***p < 0.00002.