Cerebrocrast promotes the cotransport of H+ and Cl- in rat liver mitochondria.
Considering that cerebrocrast stimulates oligomycin-inhibited state 3 respiration simultaneously with mitochondrial transmembrane potential (Deltapsi) dissipation, the mechanism underlying the uncoupler activity of cerebrocrast was assessed by its ability to permeabilize the mitochondrial inner membrane to H(+) or to K(+) or to cotransport anions with H(+). The partition coefficient of cerebrocrast in mitochondrial membrane and its ability to act as a membrane-active compound disturbing membrane lipid organization were also investigated. Cerebrocrast induced no permeabilization of mitochondrial inner membrane to H(+) or K(+), but it was able to transport H(+) in association with Cl(-). Cerebrocrast showed a strong incorporation into the mitochondrial membrane, with a partition coefficient (Kp(m/w)) of 2.7(+/-0.1)x10(5). Cerebrocrast also reduced, in a concentration dependent manner, the phase transition temperature, the cooperative unit size, and the enthalpy associated with the phase transition temperature of DMPC membrane bilayers. It was concluded that the uncoupler activity of cerebrocrast is due to its ability to promote the cotransport of H(+) with Cl(-) through the rat liver mitochondrial inner membrane, and that this cerebrocrast mechanism of action may be potentiated by alterations of membrane lipid organization and membrane lateral heterogeneity.
Fernandes
Maria A S
MA
Departamento de Zoologia, Universidade de Coimbra, 3004-517 Coimbra, Portugal. mfer@ci.uc.pt
Jurado
Amália S
AS
Videira
Romeu A
RA
Santos
Maria S
MS
Moreno
António J M
AJ
Velena
Astrida
A
Duburs
Gunars
G
Oliveira
Catarina R
CR
Vicente
Joaquim A F
JA
D000244:Adenosine Diphosphate / Q000737:chemistry; D000704:Analysis of Variance; D000818:Animals; D001692:Biological Transport; D002712:Chlorides / Q000378:metabolism*; D004095:Dihydropyridines / Q000737:chemistry / Q000494:pharmacology*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D007425:Intracellular Membranes / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008297:Male; D008564:Membrane Potentials; D008928:Mitochondria / Q000473:pathology; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D008956:Models, Chemical; D011522:Protons; D051381:Rats; D017208:Rats, Wistar; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics
D002712:Chlorides; D004095:Dihydropyridines; D008051:Lipid Bilayers; D008055:Lipids; D011522:Protons; C073838:2,6-dimethyl-3,5-bis(2'-propoxyethoxycarbonyl)-4-(2''-difluoromethoxyphenyl)-1,4-dihydropyridine; D000244:Adenosine Diphosphate; C038806:1,4-dihydropyridine; D004134:Dimyristoylphosphatidylcholine