The Distribution of Barbiturates in Model Membranes of Total Lipids and Total Phospholipids Extracted from Brain Membranes

  • Park, Chang-Sik (Department of Dental Pharmacology and Biophysics College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University) ;
  • Lee, Seong-Moon (Department of Dental Pharmacology and Biophysics College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University) ;
  • Chung, In-Kyo (Department of Orai and Maxillofacial Surgery and Clinical Pharmacology College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University) ;
  • Kim, Jin-Bom (Department of Preventive and Community Dentistry College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University) ;
  • Son, Woo-Sung (Department of Orthodontics College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University) ;
  • Jang, Hye-Ock (Department of Oriental Pathology and Prescription, College of Oriental Medicine, Dong-Eui University) ;
  • Yun, Il (Department of Dental Pharmacology and Biophysics College of Dentistry and Research Institute for Oral Biotechnology, Pusan National University)
  • Received : 2000.01.21
  • Accepted : 2000.03.09
  • Published : 2000.05.31

Abstract

The distribution of barbiturates in the model membranes of total lipids (SPMVTL) and total phospholipids (SPMVPL) extracted from synaptosomal plasma membrane vesicles was determined by employing a fluorescent probe technique. The two fluorescent probes 2-(9-anthroyl)stearic acid and 12-(9-anthroyl)stearic acid were utilized as probes for the surface and the hydrocarbon interior of the outer monolayer of the SPMVTL and SPMVPL, respectively. The Stern-Volmer equation of fluorescent quenching was modified to calculate the relative distribution. The analysis of preferential quenching of these probes by barbiturates indicates that pentobarbital, hexobarbital, amobarbital and phenobarbital are predominantly distributed on the surface area, while thiopental sodium has an accessibility to the hydrocarbon interior of the outer monolayer of the SPMVTL and SPMVPL. From these results, it is strongly suggested that the more effective penetration into the hydrocarbon interior of the outer monolayer of the membrane lipid bilayer could result in a higher general anesthetic activity.

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