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. 2021 Sep 7;10:e65667. doi: 10.7554/eLife.65667

Figure 7. ArSK/CCK1 and ArSK/CCK2 cause concentration-dependent contraction of in vitro preparations of cardiac stomach, tube foot, and apical muscle from Asterias rubens.

Figure 7.

(a) Representative recordings of the effects ArSK/CCK1 (1 µM; green arrowhead) and ArSK/CCK2 (1 µM; red arrowhead) in causing contraction of cardiac stomach preparations and compared with the effect of NGFFYamide (100 nM; black arrowhead) on the same preparation. The downward pointing grey arrowhead shows when a preparation was washed with seawater. Scale bar: vertical 0.5 mV; horizontal 1 min. (b) Concentration-response curves comparing the effects of ArSK/CCK1, ArSK/CCK2, and ArSK/CCK2(ns) on cardiac stomach preparations. The effects of peptides (means ± s.e.m.; n = 5–9) were normalized to the effect of 100 nM NGFFYamide (NGFFYa). (c) Representative recordings of the effects ArSK/CCK1 (1 µM; green arrowhead) and ArSK/CCK2 (1 µM; red arrowhead) in causing contraction of tube foot preparations and compared with the effect of acetylcholine (10 µM; black arrowhead) on the same preparation. The downward pointing grey arrowhead shows when a preparation was washed with seawater. Scale bar: vertical 0.08 mV; horizontal 1 min. (d) Concentration-response curves comparing the effects of ArSK/CCK1 and ArSK/CCK2 on tube foot preparations. The effects of peptides (means ± s.e.m.; n = 8–10) were normalized to the effect of 10 µM acetylcholine (ACh). * indicates statistically significant differences between ArSK/CCK1 and ArSK/CCK2 when tested at concentrations of 25 and 100 nM (p < 0.01 and p < 0.05, respectively) as determined by two-way ANOVA and Bonferroni’s multiple comparison test. (e) Representative recordings of the effects ArSK/CCK1 (1 µM; green arrowhead) and ArSK/CCK2 (1 µM; red arrowhead) in causing contraction of apical muscle preparations and compared to the effect of acetylcholine (10 µM; black arrowhead) on the same preparation. The downward pointing grey arrowhead shows when a preparation was washed with seawater. Scale bar: vertical 0.4 mV; horizontal 1 min. (f) Concentration-response curves comparing the effects of ArSK/CCK1 and ArSK/CCK2 on apical muscle preparations. The effects of peptides (means ± s.e.m; n = 20–23) were normalized to the effect of 10 µM acetylcholine (ACh).

Figure 7—source data 1. Data for graphs shown in Figure 7b, d and f.