Figure 4. (A) Representative trace demonstrating the dose-dependent inhibitory effect of ketamine on myocyte shortening (top) and intracellular calcium ([Ca²+]ⁱ) concentration (bottom). Ketamine was added to individual field-stimulated myocytes at the concentrations depicted in the figure. Changes in cell length were measured in micrometers. [Ca²+]ⁱwas measured as the 340/380 fluorescence ratio. (B) Exploded view of individual contractions and [Ca sup 2+]ⁱtransients taken from part A.