NMR studies of cation transport across membranes
/sup 23/Na NMR Studies of cation transport across membranes were conducted both on model and biological membranes. Two ionophores, the carrier monensin and the channel-former gramicidin, were chosen to induce cation transport in large unilamellar phosphatidylcholine vesicles. The distinction between the NMR signals arising from the two sides of the membrane was achieved by the addition of an anionic paramagnetic shift reagent to the outer solution. The kinetics of the cation transport across the membrane was observed simultaneously monitoring the changes in the /sup 23/Na NMR signals of both compartments. Two mathematical models were developed for the estimation of the transport parameters of the monensin- and gramicidin-induced cation transport. The models were able to fit the experimental data very well. A new method for the estimation of the volume trapped inside the vesicles was developed. The method uses the relative areas of the intra- and extravesicular NMR signals arising from a suspension of vesicles bathed in the same medium they contain, as a measure for the relative volumes of these compartments. Sodium transport across biological membranes was studied by /sup 23/ NMR, using suspensions of cultured nerve cells. The sodium influx through voltage-gated channels was studied using the channel modifier batrachotoxin in combination with scorpion toxin.
- Research Organization:
- State Univ. of New York, Stony Brook (USA)
- OSTI ID:
- 5007365
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALI METAL ISOTOPES
ANIMAL CELLS
ANTIGENS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
COMPARTMENTS
IONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
MATHEMATICAL MODELS
MEMBRANE TRANSPORT
MEMBRANES
NERVE CELLS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
RESONANCE
SODIUM 23
SODIUM ISOTOPES
SOMATIC CELLS
STABLE ISOTOPES
TOXIC MATERIALS
TOXINS