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Title: Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane

Abstract

The effects of local anesthetics and a divalent cation, Ca2+, on the function of rhodopsin were estimated from the measurements of light-induced proton uptake. The light-induced proton uptake by rhodopsin in the rod outer segment disk membrane was enhanced at lower pH (4) but depressed at higher pHs (6 to 8) by the tertiary amine local anesthetics lidocaine, bupivacaine, tetracaine, and dibucaine. The order of local anesthetic-induced depression of the proton uptake followed that of their clinical anesthetic potencies. The depression of the proton uptake versus the concentration of the uncharged form of local anesthetic nearly describes the same curve for small and large dose of added anesthetic. Furthermore, a neutral local anesthetic, benzocaine, depressed the proton uptake at all pHs between 4 and 7. These results indicate that the depression of the proton uptake is due to the effect of only the uncharged form. It is hypothesized that the uncharged form of local anesthetics interacts hydrophobically with the rhodopsin in the disk membrane. The dual effect of local anesthetics on the proton uptake, on the other hand, suggests that the activation of the function of rhodopsin may be caused by the charged form. There was no significant change inmore » the light-induced proton uptake by rhodopsin when 1 mM of Ca2+ was introduced into the disk membrane at varying pHs in the absence or presence of local anesthetics. This fact indicates that Ca2+ ion does not influence the diprotonating process of metarhodopsin; neither does it interfere with the local anesthetic-induced changes in the rhodopsin molecule.« less

Authors:
; ;
Publication Date:
Research Org.:
Osaka Univ. Medical School, Japan
OSTI Identifier:
5621005
Resource Type:
Journal Article
Resource Relation:
Journal Name: Anesthesiology; (United States); Journal Volume: 4
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ANESTHETICS; BIOLOGICAL EFFECTS; CELL MEMBRANES; BIOLOGICAL FUNCTIONS; PROTONS; UPTAKE; CALCIUM; CATIONS; CATTLE; DOSE-RESPONSE RELATIONSHIPS; EYES; IN VITRO; PH VALUE; RHODOPSIN; VALENCE; ALKALINE EARTH METALS; ANIMALS; BARYONS; BODY; BODY AREAS; CELL CONSTITUENTS; CENTRAL NERVOUS SYSTEM DEPRESSANTS; CHARGED PARTICLES; DOMESTIC ANIMALS; DRUGS; ELEMENTARY PARTICLES; ELEMENTS; FACE; FERMIONS; FUNCTIONS; HADRONS; HEAD; IONS; MAMMALS; MEMBRANES; METALS; NUCLEONS; ORGANIC COMPOUNDS; ORGANS; PIGMENTS; PROTEINS; RUMINANTS; SENSE ORGANS; VERTEBRATES; 550200* - Biochemistry

Citation Formats

Mashimo, T., Abe, K., and Yoshiya, I.. Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane. United States: N. p., 1986. Web. doi:10.1097/00000542-198604000-00006.
Mashimo, T., Abe, K., & Yoshiya, I.. Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane. United States. doi:10.1097/00000542-198604000-00006.
Mashimo, T., Abe, K., and Yoshiya, I.. 1986. "Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane". United States. doi:10.1097/00000542-198604000-00006.
@article{osti_5621005,
title = {Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane},
author = {Mashimo, T. and Abe, K. and Yoshiya, I.},
abstractNote = {The effects of local anesthetics and a divalent cation, Ca2+, on the function of rhodopsin were estimated from the measurements of light-induced proton uptake. The light-induced proton uptake by rhodopsin in the rod outer segment disk membrane was enhanced at lower pH (4) but depressed at higher pHs (6 to 8) by the tertiary amine local anesthetics lidocaine, bupivacaine, tetracaine, and dibucaine. The order of local anesthetic-induced depression of the proton uptake followed that of their clinical anesthetic potencies. The depression of the proton uptake versus the concentration of the uncharged form of local anesthetic nearly describes the same curve for small and large dose of added anesthetic. Furthermore, a neutral local anesthetic, benzocaine, depressed the proton uptake at all pHs between 4 and 7. These results indicate that the depression of the proton uptake is due to the effect of only the uncharged form. It is hypothesized that the uncharged form of local anesthetics interacts hydrophobically with the rhodopsin in the disk membrane. The dual effect of local anesthetics on the proton uptake, on the other hand, suggests that the activation of the function of rhodopsin may be caused by the charged form. There was no significant change in the light-induced proton uptake by rhodopsin when 1 mM of Ca2+ was introduced into the disk membrane at varying pHs in the absence or presence of local anesthetics. This fact indicates that Ca2+ ion does not influence the diprotonating process of metarhodopsin; neither does it interfere with the local anesthetic-induced changes in the rhodopsin molecule.},
doi = {10.1097/00000542-198604000-00006},
journal = {Anesthesiology; (United States)},
number = ,
volume = 4,
place = {United States},
year = 1986,
month = 4
}
  • Laser Doppler Spectroscopy has been used to measure the electrophoretic mobility of isolated bovine retinal rod outer segment disks. The mobility of dark adapted disks is found to be 0.95 ..mu..m/sec/v/cm at pH 7.0. The extrapolated isoelectric point is at pH 3.8. To within a two minute time resolution, no change in the mobility is observed upon bleaching of rhodopsin. However, a roughly 12% increase in the mobility occurs upon ultraviolet irradiation.
  • Spin-lattice relaxation times T/sub 1/ in deuterated aqueous dispersions of lecithin and rod outer segment disk membranes were measured at various concentrations and temperatures. Fast exchange between two loosely defined phases of water molecules was shown to fit the data, allowing the dynamic features of ''bound'' water and the hydration of the biological membrane to be evaluated. The state of the water was shown to be also involved in vision physiology.
  • A group of 23-29-kDa polypeptides in the membranes of bovine rod outer segments are substrates for S-adenosylmethionine-dependent methylation reactions. The bulk of the methyl group incorporation is in base-labile ester-like linkages, and does not appear to be due to the widespread D-aspartyl/L-isoaspartyl methyltransferase. To determine the site(s) of methylation, {sup 3}H-methylated proteins separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate were eluted and digested with papain, leucine aminopeptidase-M, and prolidase. After performic acid oxidation of the digest, a base-labile radioactive material was recovered that coeluted with a synthetic standard of cysteic acid methyl ester upon cation exchange and G-15more » gel filtration chromatography, as well as in two thin-layer electrophoresis and two thin-layer chromatography systems. These results provide direct evidence for the methylation of the alpha-carboxyl group of a carboxyl-terminal cysteinyl residue, a modification that has been proposed for the 21-kDa Ha-ras product and other cellular proteins.« less
  • Phase separation in artificially stacked multilayers of isolated bovine retinal rod outer segment (ROS) membranes has been examined via x-ray diffraction and electron microscopy. Specimens were prepared by isopotential spin drying followed with partial hydration by equilibration against moist gas streams. Upon dehydration, the multilamellar membrane phase assumes a binary phase composition consisting of concentrated protein-containing lamellae interspersed with microdomains of hexagonally packed tubes of lipid in a H/sub II/ configuration. The H/sub II/ lattice is geometrically coupled to the lamellar phase with one set of hexagonal crystal planes co-planar to the local membrane lamellae. The hexagonal microdomains bear amore » striking resemblance to the ''paracrystalline inclusions'' observed in fast-frozen, intact frog ROS (Corless and Costello, 1981. Exp. Eye Res. 32:217). The lamellar lattice is characterized by an unusually small degree of disorder. Sharp lamellar diffraction with a 120 angstrom unit cell is observed (at near total dehydration) to a resolution of 6 angstrom. A model consistent with the data is that a multilamellar array of ROS disks is stable as long as the external disk surfaces are kept sufficiently far apart. If the distance between the membranes is allowed to shrink below a certain critical value, the disk lipids, spontaneously convert to a nonbilayer phase. This suggests that the structure of the ROS is stabilized by an internal framework that acts to keep the disks apart from one another and from the plasmalemma. Thus, necessity of avoiding phase separations may provide a rationale for the peculiar morphology of the ROS.« less