Melittin stimulates incorporation and degradation of sphingomyelin in synaptosomal plasma membranes.
Melittin enhanced sphingomyelin (SPM) degradation by the neutral membrane-bound sphingomyelinase from calf brain synaptosomal plasma membranes (SYM) up to 20-fold. Melittin in concentrations as high as 100 microM did not significantly alter membrane fluidity of SYM as measured by fluorescence depolarization and electron spin resonance (ESR) using diphenylhexatriene and a doxyl derivative of SPM, respectively. In the concentration range 100--1000 microM, melittin was observed to rigidify SYM. The incorporation of SPM derivatives into the lipid bilayer of SYM was demonstrated by ESR measurements. Melittin enhanced the uptake of SMP-derivatives into SYM.
D000818:Animals; D001514:Bee Venoms / Q000494:pharmacology*; D002417:Cattle; D004578:Electron Spin Resonance Spectroscopy; D005454:Fluorescence Polarization; D008555:Melitten / Q000494:pharmacology*; D008560:Membrane Fluidity / Q000187:drug effects; D013010:Sonication; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism; D013109:Sphingomyelins / Q000378:metabolism*; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism
D001514:Bee Venoms; D013109:Sphingomyelins; D008555:Melitten; D013108:Sphingomyelin Phosphodiesterase