Figure 12. [Ca²⁺]_i and tension in response to PGF in solution containing 0 mM Na⁺_∘ in term human uterine smooth muscle.

Lowering Na⁺_∘ to 0 mM caused an increase in [Ca²⁺]_i (upper panel) that was small compared with the increase evoked by 100 mM K⁺ (lower panel) in 2 of 6 tissues.