title: Evidence for roles of the activating function in electric stimulation.
abstract: The hypothesis that the activating function drives transmembrane voltage changes (delta Vm) has been tested in hearts. Optical delta Vm were measured during activating functions produced with nonuniform and uniform transparent electrodes. When a nonuniform electrode was used to produce [equation: see text], the signs of delta Vm and [equation: see text] matched. The extracellular voltage gradients, often assumed important, did not predict delta Vm. When a uniform electrode was used to eliminate [equation: see text], the signs of delta Vm matched the signs of [equation: see text] estimated from variations in heart width. Demonstration of the activating function as a determinant of stimulation may improve research and therapy that use electric stimulation.
authors.affiliation: Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham 35294-0019, USA. sbk@crml.uab.edu
authors.forename: S B
authors.initials: SB
authors.lastname: Knisley
mesh_terms: D000818:Animals; D001698:Biomedical Engineering; D004558:Electric Stimulation; D006321:Heart / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology*