Reduction of the sucrose-saline interdiffusion in the sucrose gap technique by controlled compression of the extracellular space in myocardial preparations.

The time course and the extent of the sucrose-saline interdiffusion in the sucrose gap technique was investigated experimentally. 14C-sucrose diffusion and voltage clamp experiments were performed with designs of the sucrose apparatus allowing accurate control of the size of the holes in the rubber partitions defining the sucrose gap. Experiments with frog ventricular strips demonstrated that compression of the extracellular space to around 15% of its undisturbed value was possible without disturbance of the intracellular conduction pathway. The procedure reduced the sucrose-saline diffusion significantly and proved indispensible for obtaining reliable voltage-current relations in voltage clamp experiments.