Figure 7
I Ca is not stimulated by Iso. 10-6 M Iso was rapidly applied to atrial myocytes of warm-acclimated and cold-acclimated crucian carp to see if beta-adrenergic activation could increase ICa. Iso did not enhance ICa. Subsequent exposure of the cells to 10-6 M CCh reduced ICa by about 40%. Experiments were made at 18°C. The results are means ± SEM of 10 myocytes (from 4 fish) for both acclimation groups. Asterisk (*) indicates a statistically significant difference (P < 0.05) between control value and the value in the presence of CCh.