Pore-like diffusion barriers in murine cardiac myocytes.

ABSTRACT: Using both optical and electrical methods, we document that solute diffusion in the cytoplasm of BL6 murine cardiac myocytes becomes restricted >30-fold as molecular weight increases from 30 to 2000, roughly as expected for pores with dimensions of cardiac porin channels. The Bodipy-FL ATP analogue diffuses ∼50-fold slower in BL6 cardiac cytoplasm than in free water. From several fluorophores analyzed, our estimates of bound fluorophore fractions range from 0.1 for a 2 kD FITC-labeled polyethylene glycol to 0.93 for sulforhodamine. We estimate that diffusion coefficients of unbound fluorophores range from 0.5 to 8 x 10 ^-7 cm ² /s. Analysis of Na/K pump and veratridine-modified Na channel currents confirms that Na diffusion is nearly unrestricted (time constant for equ

SUBMITTER: Deisl C 

PROVIDER: S-EPMC9881867 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature