Barbiturates가 소의 대뇌피질 Synaptosomal Plasma Membrane Vesicles로 부터 추출 제제한 총지질 및 총인지질 인공세포막에 형성된 비대칭적 유동성에 미치는 비대칭적 영향

Effects of Barbiturates on Transbilayer Fluidity Domains of Phospholipid Model Membrane Monolayers

한국산 2년생 소의 신선한 대뇌피질로 부터 synaptosomal plasma membrane vesicles (SPMV)를 분리한 후 이 SPMV로 부터 추출한 총지질 (SPMVTL) 및 총인지질 (SPMVPL)로서 인공세포막을 제제하였다. SPMVTL 및 SPMVPL의 outer monolayer에 trinitrophenyl groups로 공유결합시킴으로써 형광 probe 1,6-diphenyl-1,3,5-hexatriene (DPH)의 outer monolayer 형광을 선택적으로 소광케한 후 SPMVTL 및 SPMVPL의 inner와 outer monolayer 사이의 비대칭적 유동성 존재 유무를 확인하였던 바 inner monolayer에 비하여 outer monolayer가 유동성이 크다는 것을 확인하였으며 SPMVTL에 비하여 SPMVPL의 유동성이 높았다. 뿐만 아니라 barbiturates는 SPMVTL의 유동성에 대하여는 유의성이 있을 만큼의 증감 효과를 나타내지 않았고 SPMVPL의 유동성은 감소시키되 주로 outer monolayer의 유동성을 감소시킨다는 것을 확인하였으며 barbiturates 종류에 따른 SPMVPL의 총유동성 감소의 크기는 pentobarbital > hexobarbital > amobarbital > phenobarbital의 순이었다.

Selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups was utilized to examine the transbilayer fluidity domains of the model membranes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from synaptosomal plasma membrane vesicles. At $37^{\circ}C$, all anisotropy (r), limiting anisotropy $(r_{\infty})$, and order parameter (S) values of DPH in the SPMVTL were larger than those in SPMVPL. The anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.025, 0.033, and 0.070, respectively, greater than calculated for the outer monolayer of SPMVTL. In SPMVPL, the anisotropy, limiting anisotropy, and order parameter of DPH in the inner monolayer were 0.014, 0.018, and 0.047, respectively, greater than calculated for the outer monolayer. Selective quenching of DPH by trinitrophenyl groups was also utilized to examine the effects of barbiturates on the transbilayer fluidity domains of SPMVTL and SPMVPL. Barbiturates did not affect the anisotropy of DPH in the transbilayer domains of SPMVTL. In contrast, barbiturates increased the fluorescence anisotropy, limiting anisotropy, and order parameter of DPH in the SPMVPL in a dose-dependent manner. Barbiturates showed a greater ordering effect on the outer monolayer as compared to the inner monolayer of SPMVPL. Hence, it has been demonstrated for the first time that the Sheetz-Singer hypothesis (1974) may be valid for phospholipid model membranes.