Effects of dimyristoylphosphatidylethanol and ethanol on thickness of neuronal membrane lipid bilayers.
The aim of this study was to provide a basis for examining the molecular mechanism for the pharmacological action of ethanol. Energy transfer between the surface fluorescent probe 1-anilinonaphthalene-8-sulfonic acid and hydrophobic fluorescent probe 1,3-di(1-pyrenyl)propane was used to examine the effect of both dimyristoylphosphatidylethanol (DMPEt) and ethanol on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex. The thickness (D) of the intact SPMV was 1.044 +/- 0.008 (arbitrary units, n=5) at 37 degrees C (pH 7.4). Both DMPEt and ethanol decreased the thickness of the SPMV lipid bilayer in a dose-dependent manner with a significant decrease in thickness observed at 5 microM and 25 mM, respectively. It was assumed that both ethanol and DMPEt cause interdigitation in the SPMV lipid bilayers. The effects of ethanol on the neuronal membranes were attributed to its direct and indirect actions. The indirect action of ethanol refers to the action of phosphatidylethanol, which is an ethanol abnormal metabolite, on the neuronal membranes. The decrease in membrane thickness by both DMPEt and ethanol might be responsible for some, but not all of its anesthetic actions.
Park
Jun-Seop
JS
Department of Dental Pharmacology, School of Dentistry, Pusan National University, Yangsan, Korea.
Choi
Eun-Jong
EJ
Jeong
Dong-Soo
DS
Yang
Hak-Jin
HJ
Kim
Kyoung-Phil
KP
Son
Kuk-Kyung
KK
Lee
Hyun-Wook
HW
Kang
Min-Jung
MJ
Kim
Sang-Min
SM
Chung
In-Kyo
IK
Bae
Moon-Kyung
MK
Jang
Hye-Ock
HO
Yun
Il
I
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004735:Energy Transfer / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology*; D020404:Glycerophospholipids / Q000494:pharmacology*; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D013574:Synaptosomes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure
C104364:1,2-dimyristoyl-sn-glycero-3-phosphatidylethanol; D020404:Glycerophospholipids; D008051:Lipid Bilayers; D000431:Ethanol