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Role of anion‐cation interactions on the pre‐steady‐state currents of the rat $Na^{+}‐Cl^{−}$‐dependent GABA cotransporter rGAT1
| Content Provider | Scilit |
|---|---|
| Author | Bossi, Elena Giovannardi, Stefano Binda, Francesca Forlani, Greta Peres, Antonio |
| Copyright Year | 2002 |
| Description | Journal: The Journal of physiology The effects of sodium and chloride on the properties of the sodium-dependent component of the ‘pre-steady-state’ currents of rGAT1, a GABA cotransporter of the $Na^{+}-Cl^{−}$-dependent family, were studied using heterologous oocyte expression and voltage clamp. Reductions in either extracellular sodium or chloride shifted the charge-voltage (Q-V) and time constant-voltage (τ-V) characteristics of the process towards more negative potentials. The shift induced by sodium $(TMA^{+}$, tetramethylammonium substitution) was stronger than that induced by chloride (acetate substitution), and the shift of τ was accompanied by a decrease in its maximum value. Increasing extracellular $Ca^{2+}$ did not produce significant shifts in Q-V and τ-V curves. The negative shift of the Q-V curve upon chloride reduction and the decrease in the value of the relaxation time constant, τ, when either sodium or chloride were lowered, contrasted with the prediction of the Hill-Boltzmann interpretation of the process. Analysis of the unidirectional rate constants under different conditions revealed that both sodium and chloride shifted the outward rate more than the inward rate; furthermore, the shifts induced by sodium were larger than those induced by chloride. These observations are qualitatively compatible with the existence of a selective vestibule at the mouth of the transporters, acting similarly to a Donnan system. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290322/pdf |
| Ending Page | 350 |
| Page Count | 8 |
| Starting Page | 343 |
| ISSN | 00223751 |
| e-ISSN | 14697793 |
| DOI | 10.1113/jphysiol.2001.013457 |
| Journal | The Journal of physiology |
| Issue Number | 2 |
| Volume Number | 541 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 2002-06-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Journal of physiology Sodium and Chloride |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology Sports Science |
