The overall aim of this project is to describe the mechanisms by which the numbers and properties of ion channels in the membranes of excitable cells can be modulated during development. The specific experiments of this proposal will be done on oocytes and early embryos of starfish and tunicates. Patch clamp techniques will be used to map the spatial distribution of Ca and K channels over the surface of the starfish oocyte, at different stages of oogenesis and hormone-induced maturation. The general hypothesis will be tested that Ca and K channels are clustered in different regions of the oocyte membrane, and that this clustering is reflected in the distinct ways in which Ca and K currents behave during the various events of pre-fertilization development. Patch clamp and whole-cell suction pipet clamp techniques will be used on oocytes and isolated blastomeres of the tunicate, in order to describe the development of blastomere electrical properties in relation to known cell lineages. The tunicate is very useful for this type of study, because developmental fates of various regions of the embryo are known even at the 1-cell stage, where segregated pigment granules mark the location of the different presumptive tissue types. The spatial location of ion channels will be mapped in relation to these visible developmental markers. The internal perfusion capability of the whole-cell clamp will also be used to study the role of diffusible cytoplasmic modulators in the development of ion channel properties. The results obtained will be relevant to pathologies affecting hormone-induced oocyte maturation, fertilization, and the development of excitable cells in the nervous, muscular, and immune systems.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD017486-05
Application #
3314494
Study Section
Physiology Study Section (PHY)
Project Start
1983-04-01
Project End
1991-03-31
Budget Start
1987-04-01
Budget End
1988-03-31
Support Year
5
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Arts and Sciences
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Davidson, Brad; Swalla, Billie J (2002) A molecular analysis of ascidian metamorphosis reveals activation of an innate immune response. Development 129:4739-51
Dallman, J E; Dorman, J B; Moody, W J (2000) Action potential waveform voltage clamp shows significance of different Ca2+ channel types in developing ascidian muscle. J Physiol 524 Pt 2:375-86
Moody, W J (1998) The development of voltage-gated ion channels and its relation to activity-dependent development events. Curr Top Dev Biol 39:159-85
Dallman, J E; Davis, A K; Moody, W J (1998) Spontaneous activity regulates calcium-dependent K+ current expression in developing ascidian muscle. J Physiol 511 ( Pt 3):683-93
Greaves, A A; Davis, A K; Dallman, J E et al. (1996) Co-ordinated modulation of Ca2+ and K+ currents during ascidian muscle development. J Physiol 497 ( Pt 1):39-52
Davis, A K; Greaves, A A; Dallman, J E et al. (1995) Comparison of ionic currents expressed in immature and mature muscle cells of an ascidian larva. J Neurosci 15:4875-84
Villaz, M; Cinniger, J C; Moody, W J (1995) A voltage-gated chloride channel in ascidian embryos modulated by both the cell cycle clock and cell volume. J Physiol 488 ( Pt 3):689-99
Linsdell, P; Moody, W J (1995) Electrical activity and calcium influx regulate ion channel development in embryonic Xenopus skeletal muscle. J Neurosci 15:4507-14
Linsdell, P; Moody, W J (1994) Na+ channel mis-expression accelerates K+ channel development in embryonic Xenopus laevis skeletal muscle. J Physiol 480 ( Pt 3):405-10
Nevitt, G A; Dittman, A H; Quinn, T P et al. (1994) Evidence for a peripheral olfactory memory in imprinted salmon. Proc Natl Acad Sci U S A 91:4288-92

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