Slow currents through single sodium channels of the adult rat heart - PubMed (original) (raw)
Slow currents through single sodium channels of the adult rat heart
J B Patlak et al. J Gen Physiol. 1985 Jul.
Abstract
The currents through single Na+ channels from the sarcolemma of ventricular cells dissociated from adult rat hearts were studied using the patch-clamp technique. All patches had several Na+ channels; most had 5-10, while some had up to 50 channels. At 10 degrees C, the conductance of the channel was 9.8 pS. The mean current for sets of many identical pulses inactivated exponentially with a time constant of 1.7 +/- 0.6 ms at -40 mV. Careful examination of the mean currents revealed a small, slow component of inactivation at pulse potentials ranging from -60 to -30 mV. The time constant of the slow component was between 8 and 14 ms. The channels that caused the slow component had the same conductance and reversal potential as the fast Na+ currents and were blocked by tetrodotoxin. The slow currents appear to have been caused by repeated openings of one or more channels. The holding potential influenced the frequency with which such channel reopening occurred. The slow component was prominent during pulses from a holding potential of -100 mV, while it was very small during pulses from -140 mV. Ultraslow currents through the Na+ channel were observed occasionally in patches that had large numbers of channels. They consisted of bursts of 10 or more sequential openings of a single channel and lasted for up to 150 ms. We conclude that the single channel data cannot be explained by standard models, even those that have two inactivated states or two open states of the channel. Our results suggest that Na+ channels can function in several different "modes," each with a different inactivation rate.
Similar articles
- Cardiac Na currents and the inactivating, reopening, and waiting properties of single cardiac Na channels.
Kunze DL, Lacerda AE, Wilson DL, Brown AM. Kunze DL, et al. J Gen Physiol. 1985 Nov;86(5):691-719. doi: 10.1085/jgp.86.5.691. J Gen Physiol. 1985. PMID: 2415670 Free PMC article. - Two modes of gating during late Na+ channel currents in frog sartorius muscle.
Patlak JB, Ortiz M. Patlak JB, et al. J Gen Physiol. 1986 Feb;87(2):305-26. doi: 10.1085/jgp.87.2.305. J Gen Physiol. 1986. PMID: 2419486 Free PMC article. Review. - Characteristics of action potentials and their underlying outward currents in rat taste receptor cells.
Chen Y, Sun XD, Herness S. Chen Y, et al. J Neurophysiol. 1996 Feb;75(2):820-31. doi: 10.1152/jn.1996.75.2.820. J Neurophysiol. 1996. PMID: 8714655 - Modulation of single cardiac sodium channels by DPI 201-106.
Nilius B, Benndorf K, Markwardt F, Franke T. Nilius B, et al. Gen Physiol Biophys. 1987 Oct;6(5):409-24. Gen Physiol Biophys. 1987. PMID: 2448182 - Fast Na+ channels and slow Ca2+ current in smooth muscle from pregnant rat uterus.
Sperelakis N, Inoue Y, Ohya Y. Sperelakis N, et al. Mol Cell Biochem. 1992 Sep 8;114(1-2):79-89. Mol Cell Biochem. 1992. PMID: 1281264 Review.
Cited by
- Generative Models of Brain Dynamics.
Ramezanian-Panahi M, Abrevaya G, Gagnon-Audet JC, Voleti V, Rish I, Dumas G. Ramezanian-Panahi M, et al. Front Artif Intell. 2022 Jul 15;5:807406. doi: 10.3389/frai.2022.807406. eCollection 2022. Front Artif Intell. 2022. PMID: 35910192 Free PMC article. Review. - Delayed Ventricular Repolarization and Sodium Channel Current Modification in a Mouse Model of Rett Syndrome.
Cheng H, Charles I, James AF, Abdala AP, Hancox JC. Cheng H, et al. Int J Mol Sci. 2022 May 20;23(10):5735. doi: 10.3390/ijms23105735. Int J Mol Sci. 2022. PMID: 35628543 Free PMC article. - Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going?
Horváth B, Szentandrássy N, Almássy J, Dienes C, Kovács ZM, Nánási PP, Banyasz T. Horváth B, et al. Pharmaceuticals (Basel). 2022 Feb 15;15(2):231. doi: 10.3390/ph15020231. Pharmaceuticals (Basel). 2022. PMID: 35215342 Free PMC article. Review. - Dysfunctional Nav1.5 channels due to SCN5A mutations.
Han D, Tan H, Sun C, Li G. Han D, et al. Exp Biol Med (Maywood). 2018 Jun;243(10):852-863. doi: 10.1177/1535370218777972. Epub 2018 May 27. Exp Biol Med (Maywood). 2018. PMID: 29806494 Free PMC article. Review. - Late sodium current associated cardiac electrophysiological and mechanical dysfunction.
Yu S, Li G, Huang CL, Lei M, Wu L. Yu S, et al. Pflugers Arch. 2018 Mar;470(3):461-469. doi: 10.1007/s00424-017-2079-7. Epub 2017 Nov 10. Pflugers Arch. 2018. PMID: 29127493 Review.