T-type and N-type calcium channels of Xenopus oocytes: evidence for specific interactions with beta subunits
| Autor: | Antonio Castellano, Edward Perez-Reyes, Xiangyang Wei, Antonio E. Lacerda, A. M. Brown |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
medicine.medical_specialty
Macromolecular Substances Xenopus Biophysics Mollusk Venoms Endogeny Membrane Potentials 03 medical and health sciences Xenopus laevis 0302 clinical medicine omega-Conotoxin GVIA Internal medicine medicine Animals Omega-Conotoxin GVIA Beta (finance) 030304 developmental biology Membrane potential 0303 health sciences biology Voltage-dependent calcium channel Calcium channel Cell Membrane Brain biology.organism_classification Calcium Channel Blockers Rats Endocrinology biology.protein Oocytes Female Calcium Channels Peptides 030217 neurology & neurosurgery ATP synthase alpha/beta subunits Research Article |
| Zdroj: | Biophysical Journal. 66(6):1833-1843 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/s0006-3495(94)80977-4 |
| Popis: | We used amplifying effects of calcium channel beta subunits to identify endogenous calcium channels in Xenopus oocytes. Expression of rat brain beta 4 increased macroscopic endogenous current magnitude with a small effect on kinetics. In contrast, expression of rat brain/cardiac beta 2 produced a much larger increase in current magnitude and dramatically slowed current decay. Low concentrations of omega-conotoxin GVIA irreversibly blocked currents in both uninjected and beta 2-injected oocytes. Single channel recordings revealed both T- and N-type calcium channels with conductances of 9 and 18 pS, respectively, in uninjected oocytes and in oocytes expressing either beta subunit. Expression of either beta subunit slowed average current decay of T-type single channels. Slowing of T-type current decay by expression of beta 2 was due to reopening of the channels. N-type single channel average current decay showed little change with expression of beta 4, whereas expression of beta 2 slowed average current decay. |
| Databáze: | OpenAIRE |
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