Figure 1
Effects of CCh on contractility of crucian carp heart. Concentration dependent effects of CCh on heart rate and atrial contractility in warm-acclimated and cold-acclimated crucian carp at the acclimation temperatures of the fish. (A) Depression of heart rate and force of atrial contraction (Fmax) by CCh. Note the difference in CCh sensitivity between heart rate and force of contraction. The inset indicates the effect of 3·10-6 M atropine and 100 μM L-NMMA on the responses. (B) Effect of CCh on the duration of atrial contraction (DC). The inset shows blockade of the response in the presence of atropine. The results are means ± SEM of 15 and 19 fish for cold-acclimated and warm-acclimated fish, respectively.