Barbiturates가 소의 신선한 대뇌피질 Synaptosomal Plasma Membrane Vesicles로 부터 추출하여 제제한 Phosphatidylethanolamine 인공세포막의 유동성에 미치는 영향

Effects of Barbiturates on the Fluidity of Phosphatidylethanolamine Model Membranes

Barbiturates가 분자적 약리작용기전 탐구에 기초자료를 제공하기 위하여 소의 신선한 대뇌피질 synaptosomal plasma membrane vesicles로부터 분리제제한 phosphatidylethanolamine인공세포막(SPMVPE)의 유동성에 미치는 barbiturates의 영향을 형광 probe법으로 검색한 결과는 다음과 같다. 1. Pentobarbital, hexobarbital, amobarbital 및 phenobarbital이 기재한 순위로 SPMVPE내 Py-3-Py의 monomer 형광세기에 대한 excimer 형광세기의 비 (I'/I)를 감소시켰다. 2. Pentobarbital, hexobarbital, amobarbital 및 phenobarbital이 기재한 순위로 SPMVPE내 DPH의 polarization, anisotropy, limiting anisotropy, order parameter 및 rotational relaxation time을 증가시켰다. 3. 따라서 위에 제시한 barbiturates가 SPMVPE의 유동성을 유의성있게 감소시킨다는 것을 확인할 수가 있었다.

Intramolecular excimer formation with 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization with 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to evaluate the effects of barbiturates on the bulk fluidity of the model membranes of phosphatidylethanolamine fraction of synaptosomal plasma membrane vesicles (SPMVPE) isolated from bovine cerebral cortex. In the SPMVPE, barbiturates decreased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py and increased the fluorescence polarization (P), anisotropy (r), limiting anisotropy $(r_{8})$, order parameter (S) and rotational relaxation time $({\bar{P}})$ of DPH in a dose-dependent manner. The relative potencies of barbiturates to order the SPMVPE were in the order: pentobarbital > hexobarbital > amobarbital > phenobarbital. Hence, it is concluded that barbiturates have ordering effects on the SPMVPE. And the membrane-ordering potencies of barbiturates appear to be correlated with the potencies for enhancement of GABA-stimulated chloride influx and with the anesthetic effects of barbiturates.