Figure 4
Activation of the inward rectifier potassium current by CCh. Induction of the IK,CCh by CCh in atrial myocytes from warm-acclimated and cold-acclimated crucian carp heart. Concentration-dependent increases in density of the IK,CCh for outward current (left) and representative recordings of the CCh-induced potassium current (red line) from a warm-acclimated atrial myocyte at 18°C, comparison with the background inward rectifier current, IK1 (blue line). Note the weak inward rectification of IK,CCh in comparison to IK1. The experiments were conducted at 4°C and 18°C for both acclimation groups. The results are means ± SEM of 10 myocytes (from 4 fish) for both acclimation groups. Asterisk (*) indicates a statistical difference (P < 0.05) in density of IK1 current between cold-acclimated and warm-acclimated fish at 18°C.