| Autor: |
Stevens, Edward B., Cox, Peter J., Shah, Bhaval S., Dixon, Alistair K., Richardson, Peter J., Pinnock, Robert D., Lee, Kevin |
| Předmět: |
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| Zdroj: |
Pflügers Archiv: European Journal of Physiology; Jan2001, Vol. 441 Issue 4, p481-488, 8p |
| Abstrakt: |
This study investigated the distribution of β3 in human tissues and the functional effects of the human β3 subunit on the gating properties of brain and skeletal muscle α subunits. Using RT-PCR of human cDNA panels, β3 message was detected in brain, heart, kidney, lung, pancreas and skeletal muscle. Both αIIA and SkM1 expressed in Xenopus oocytes inactivated with a time course described by two exponential components representing fast and slow gating modes, while co-expression of human β3 with αIIA or SkM1 significantly increased the proportion of channels operating by the fast gating mode. In the presence of β3 a greater proportion of αIIA or SkM1 current was described by the fast time constant for both inactivation and recovery from inactivation. β3 caused a hyperpolarizing shift in the voltage dependence of inactivation of αIIA and reduced the slope factor. The voltage dependence of inactivation of SkM1 was described by a double Boltzmann equation. However, SkM1 co-expressed with β3 was described by a single Boltzmann equation similar to one of the Boltzmann components for SkM1 expressed alone, with a small positive shift in V1/2 value and reduced slope factor. This is the first study demonstrating that β3 is expressed in adult mammalian skeletal muscle and can functionally couple to the skeletal muscle α subunit, SkM1. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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