On the effect of lysophosphatidylcholine, platelet activating factor and other surfactants on calcium permeability in sarcoplasmic reticulum vesicles.
The effect of low concentrations of lysophosphatidylcholine (LPC), platelet-activating factor (PAF) and other surfactants (Triton X-100, C12E8, sodium dodecyl sulfate, sodium cholate and sodium deoxycholate) on membrane permeability of native sarcoplasmic reticulum vesicles and sarcoplasmic reticulum lipid vesicles, has been studied. Triton X-100, C12E8, sodium dodecyl sulfate, sodium cholate and sodium deoxycholate were all able to permeabilize membranes at concentrations of surfactants below their critical micellar concentration (CMC) in both lipid and native vesicles, being the K0.5 of calcium release from native vesicles lower than that from lipid vesicles. The values of these K0.5 were well correlated with the corresponding CMC values for each type of membrane. However, both LPC and PAF behaved in a different way since, although they induced permeabilization of the native vesicles at values of K0.5 close to their CMC, their K0.5 values for permeabilizing vesicles, prepared by using lipids extracted from sarcoplasmic reticulum, were much higher than their corresponding CMC.
Teruel
J A
JA
Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de Murcia, Spain.
Soler
F
F
Gómez-Fernández
J C
JC
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D007700:Kinetics; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D008823:Micelles; D009132:Muscles / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D013501:Surface-Active Agents / Q000494:pharmacology*
D008244:Lysophosphatidylcholines; D008823:Micelles; D010972:Platelet Activating Factor; D013501:Surface-Active Agents; C006065:We 201; D002118:Calcium