Methodologies to Study Channel-Mediated Ion Fluxes in Membrane Vesicles
The use of techniques such as voltage clamp or patch clamp has provided a great deal of information about channel properties and about ion movement across ion channels in biological membranes. However, neither of these techniques can be used to study the presence and properties of ion channels in very small cells or in internal membranes such as the sarcoplasmic reticulum of skeletal muscle. A clever technique developed by Miller and Racker (1976) has made it possible to overcome these problems: the membrane of interest, once isolated and purified, is allowed to fuse to an artificial planar lipid bilayer under appropriate conditions. Thus, ion channels and probably other membrane components are incorporated into the artificial membrane (for a review on the technique, see Miller, 1983a,b). Using this approach, various channels have been studied, including a voltage-gated K+ channel from sarcoplasmic reticulum (Miller, 1978), a Cl- channel from Torpedo electroplax (White and Miller, 1979), and a Ca2+-activated K+ channel from skeletal muscle transverse tubule (Latorre et al., 1982). None of these channels was known to exist before these experiments were done.
KeywordsSarcoplasmic Reticulum Membrane Vesicle Vesicle Volume Fast Fraction Transverse Tubule
Unable to display preview. Download preview PDF.
- Andersen, O., 1978, Permeability properties of unmodified lipid bilayer membranes, in Membrane Transport in Biology, Vol. I (D. Tosteson, ed.), Springer-Verlag, Berlin, Heidelberg, New York, pp. 369–439.Google Scholar
- Coronado, R., and Miller, C., 1982, Conduction and block by organic cations in a K+-Google Scholar
- selective channel from sarcoplasmic reticulum incorporated into planar bilayers, J. Gen. Physiol. 79:529–547.Google Scholar
- Miller, C., 1983a, Integral membrane channels: Studies in model membranes, Physiol. Rev. 63:1209–1242.Google Scholar
- Miller, C., 1983b, First steps in the reconstruction of ionic channel function in model membranes, in Current Methods in Cellular Neurobiology Vol. 3, (J. Barber, ed), pp. 1–37, John Wiley & Sons, New York.Google Scholar
- Stacey, K., 1956, Light Scattering in Physical Chemistry, Academic Press, New York.Google Scholar
- Sten-Knudsen, O., 1978, Passive transport processes, in Membrane Transport in Biology, Vol. I (D. Tosteson, ed.), Springer-Verlag, Berlin, Heidelberg, New York, pp. 5–112.Google Scholar
- White, M., and Miller, C., 1979, A voltage-gated anion channel from electric organ of Torpedo californica,J. Biol. Chem. 254:10160–10166.Google Scholar