|題名: ||Molecular actions of local anesthetics in pig brain and spinal cord|
|作者: ||簡素芳;Chien, Su-fang;Yen, F. S.;Chang, C. P.;Lin, C. T.|
|出版者: ||American Chemical Society (ACS)|
|摘要: ||Photophysical properties of dibucaineqHC1 (DH+, a representative local anesthetic drug) in different regions of pig brain and spinal cord were investigated by emissiodexcitation spectroscopy. At 77 K, the observed fluorescence band, maximum at 360 nm, and phosphorescence vibronic structures at 450, 485, and 520 nm indicate that the drug action species in the nervous system is a neutral dibucaine (D) located at an action site having a polar environment. The DH’ anesthetic drug deprotonates at the plasma membrane surface, and then the resultant D species partitions into the interaction site of the nervous system. At room temperature, it was surprising to observe a strong intramolecular charge-transfer (ICT) band at 432 nm in addition to the normal fluorescence band at 390 nm. The ICT band originates from the N of the tertiary amine group to the quinoline analog of neutral dibucaine. When the selective sections of the drug-soaked spinal cord (Le., central canal/gray matter, white matter, and surface plasma membrane) were examined separately, the neutral dibucaine
species was identified to embed in a hydrophobic environment of the white and gray matter regions. These results could shed some light on the local anesthetic action mechanisms at the molecular level. The following possible local anesthetic drug actions in pig brain and spinal cord are discussed: (1) the drug transport mechanisms due to the dynamic processes of deprotonation-reprotonation (D/DHf) in dibucaines, (2) the effects of the ICT nature of the drugs on the generation of electrical signaling in nerve cells and the adsorption and delivery of drugs across nerve membranes, and (3) the interference of releasing, receptor binding, and removal of neurotransmitters by the drug partition of D/DH+ into the nervous system.
|關聯: ||Journal of physical chemistry 99(48), pp.17442-17448|