title: Influence of cholesterol depletion in plasma membrane of rat brain synaptosomes on calcium-dependent and calcium-independent exocytosis.
abstract: It is well established that calcium-dependent neurotransmitter release and exocytosis can be regulated by altering the cholesterol content of the plasma membrane. We have compared the influence of cholesterol depletion of synaptosomal plasma membrane by 15 mM methyl-beta-cyclodextrin (MCD) treatment on calcium-dependent release of D-[(3)H]aspartate induced by the calcium ionophore A23187 and on calcium-independent release induced by hypertonic shrinking or polyvalent cations. We found that decrease of cholesterol concentration by 9.3% inhibited calcium-dependent release of d-[(3)H]aspartate induced by calcium ionophore A23187 by four times while release induced by 300 microM Gd(3+), 150 mM and 500 mM sucrose remained unchanged. Further we have investigated the influence of MCD on exocytosis monitored by the fluorescent dye, acridine orange. Cholesterol depletion inhibited calcium-dependent exocytosis induced by calcium ionophore A23187 but had virtually no influence on calcium-independent exocytosis induced by hypertonic shrinking or Gd(3+). In summary, we found that the cholesterol content in synaptosomal plasma membrane is important for calcium-dependent exocytosis.
authors.affiliation: Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus.
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Waseem
authors.forename: Viktoriya A
authors.initials: VA
authors.lastname: Kolos
authors.forename: Liudmila P
authors.initials: LP
authors.lastname: Lapatsina
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Fedorovich
mesh_terms: D000165:Acridine Orange; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D005089:Exocytosis; D005456:Fluorescent Dyes; D005682:Gadolinium / Q000494:pharmacology; D006982:Hypertonic Solutions / Q000494:pharmacology; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013574:Synaptosomes / Q000378:metabolism*; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D005456:Fluorescent Dyes; D006982:Hypertonic Solutions; D007476:Ionophores; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D001224:Aspartic Acid; D000001:Calcimycin; D002784:Cholesterol; D005682:Gadolinium; D000165:Acridine Orange; C038958:gadolinium chloride; D002118:Calcium