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Titolo:
EFFECTS OF METHYLPARATHION ON MEMBRANE FLUIDITY AND ITS IMPLICATIONS FOR THE MECHANISMS OF TOXICITY
Autore:
LOPES VICF; ANTUNESMADEIRA MC; MADEIRA VMC;
Indirizzi:
UNIV COIMBRA,DEPT ZOOL,CTR NEUROCIENCIAS P-3049 COIMBRA PORTUGAL
Titolo Testata:
Toxicology in vitro
fascicolo: 4, volume: 11, anno: 1997,
pagine: 337 - 345
SICI:
0887-2333(1997)11:4<337:EOMOMF>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
NATIVE MEMBRANES; PHASE-EQUILIBRIA; DIPHENYLHEXATRIENE; MODEL; INSECTICIDES; POLARIZATION; ORGANIZATION; PARTITION; PARATHION; BILAYERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
33
Recensione:
Indirizzi per estratti:
Citazione:
V.I.C.F. Lopes et al., "EFFECTS OF METHYLPARATHION ON MEMBRANE FLUIDITY AND ITS IMPLICATIONS FOR THE MECHANISMS OF TOXICITY", Toxicology in vitro, 11(4), 1997, pp. 337-345

Abstract

As probed by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 3-[p-(6-phenyl)-1,3,5-hexatrienyl] phenylpropionic acid (DPH-PA), methylparathion decreases the phase transition midpoint of dimyristoylphosphatidylcholine (DMPC) bilayers and broadens the transition profile. Furthermore, the insecticide orders to some extent the fluid phase of DMPC, in either the hydrophobic core or in the outer regions of the membrane, as evaluated by DPH and DPH-PA, respectively. These condensing effects of methylparathion were further confirmed in fluid models of egg-yolk phosphatidylcholine. The insecticide increases tosome extent the ordering promoted by cholesterol in fluid bilayers ofDMPC, but high cholesterol concentrations (greater than or equal to 30 mol%) prevent methylparathion interaction. In agreement with the data in models of synthetic lipids, the condensing effects of methylparathion in fluid native membranes of mitochondria, sarcoplasmic reticulumand erythrocytes are depressed with the increase in intrinsic cholesterol. Therefore, the effects of methylparathion are modulated, to a great extent, by membrane cholesterol concentration. Consequently, it can be suggested that the fluidity effects of methylparathion would be preferentially exerted in biomembranes scarce in cholesterol, e.g. mitochondria and sarcoplasmic reticulum. The perturbations promoted by methylparathion in these highly functional membranes will certainly induce bioenergetic alterations endangering cell and tissue functions, since membrane fluidity is a crucial parameter in the control of basic membrane mechanisms and, consequently, in cell homoeostasis. (C) 1997 Elsevier Science Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/08/20 alle ore 20:04:46