Figure 5. Effect of Na⁺-K⁺ pump inhibition on force at 4 and 9 mM K⁺ at 20 and 30 °C.

Experimental conditions as in Fig 1A. Ouabain (10⁻⁵ M) was added 15 min prior to temperature elevation as indicated by arrows. •, 4 mM K⁺ throughout. ▵, [K⁺]_o changed from 4 to 9 mM after 50 min. Each point indicates the mean of observations from 6 muscles with error bars showing S.E.M.