Diazepam enhances intrasynaptosomal free calcium concentrations.
Synaptosomes prepared from brains of rats were incubated in different concentrations of diazepam under conditions designed to reduce the action of a reversed Na+/Ca2+ exchanger. In synaptosomes depolarized in the presence of added Ca2+, doses of diazepam ranging from 0.1 to 100 microM were found to significantly enhance Ca2+ levels measured with the fluorescent dye fura-2, compared to control incubations without drug. Furthermore, doses of diazepam as low as 1 microM significantly increased the concentration of Ca2+ in non-depolarized synaptosomes without added Ca2+ in the medium. The effects of depolarization and diazepam treatment were synergistic in increasing the levels of intrasynaptosomal Ca2+.
Martin
J V
JV
Department of Biology, Rutgers University, Camden, N.J. 08102.
Keir
D R
DR
Lee
H Y
HY
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D003975:Diazepam / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D016257:Fura-2; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D019831:Sodium-Calcium Exchanger; D013050:Spectrometry, Fluorescence; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology
D002352:Carrier Proteins; D019831:Sodium-Calcium Exchanger; D003975:Diazepam; D016257:Fura-2