Figure 5. Effect of rat amylin and insulin on tetanic contractions of soleus muscle exposed to buffer containing 12.5 mm K⁺.

Isolated muscles were mounted in force transducers in a thermostatically controlled (30 °C) chamber containing Krebs-Ringer bicarbonate buffer continuously bubbled with a mixture of 95 % O₂ and 5 % CO₂. Active force development during 2 s of 30 Hz stimulation was recorded at 5 min intervals, and the mean value of these measurements (the starting control level) is indicated by the dashed line. After 30 min of equilibration, K⁺ was increased to 12.5 mm, and after 120 min, at the arrow, amylin (10⁻⁸m), insulin (0.7 × 10⁻⁸m) or the two hormones combined were added, and recordings continued. Each point represents the mean of observations on six muscles with bars denoting s.e.m.