AJP - Cell Physiology, Vol 257, Issue 6 C1142-C1148, Copyright © 1989 by American Physiological Society
Evidence for two distinct chloride uniport pathways in brown adipose tissue mitochondria
P. Jezek, A. D. Beavis, D. J. Diresta, R. N. Cousino and K. D. Garlid
Department of Pharmacology, Medical College of Ohio, Toledo 43699.
Chloride permeability of the inner membrane of brown adipose tissue
mitochondria was analyzed by monitoring mitochondrial swelling in KCl salts
in the presence of K+ ionophores. The results indicate that the high anion
conductance observed in these mitochondria is due to the presence of two
separate pathways: 1) a Cl-conducting pathway that is inhibited by
guanosine 5'-diphosphate (GDP) but neither by N,N'-dicyclohexylcarbodiimide
(DCCD) nor by amphiphilic amines and that is found uniquely in brown
adipose tissue mitochondria and 2) an inner membrane anion uniport channel
that is inhibited both by DCCD and by amphiphilic amines but not by GDP and
that is opened either by depletion of matrix Mg2+ or by alkalinization of
the matrix.
