“In the absence of extracellular Ca, contractile responses to ACh or KCl decrease as the preincubation time or the EDTA concentration increases.”
“Prolonged incubation in the presence of EDTA (1 mmol/l) promotes a delay in the recovery of the tonic component of the contraction elicited subsequently by acetylcholine and KCl in physiological salt solution, and abolishes the phasic one.”