P2X receptors in cochlear Deiters' cells
| Autor: | Chen, Chu, Bobbin, Richard P |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1998 |
| Předmět: |
Purinergic P2 Receptor Agonists
Adenosine Patch-Clamp Techniques Dose-Response Relationship Drug Receptors Purinergic P2 Vasodilator Agents Vestibular Nucleus Lateral Colforsin Guinea Pigs Uridine Triphosphate Thionucleotides Cochlea Adenosine Diphosphate Enzyme Activation Adenosine Triphosphate 1-Methyl-3-isobutylxanthine Papers Animals Tetradecanoylphorbol Acetate Calcium Protein Kinases Receptors Purinergic P2X2 |
| Popis: | 1. The ionotropic purinoceptors in isolated Deiters' cells of guinea-pig cochlea were characterized by use of the whole-cell variant of the patch-clamp technique. 2. Extracellular application of adenosine 5'-triphosphate (ATP) induced a dose-dependent inward current when the cells were voltage-clamped at -80 mV. The ATP-induced current showed desensitization and had a reversal potential around -4 mV. 3. Increasing intracellular free Ca2+ by decreasing the concentration of EGTA in the pipette solution reduced the amplitude of the ATP-gated current. 4. The order of agonist potency was: 2-methylthioATP (2-meSATP)ATPbenzoylbenzoyl-ATP (BzATP)alpha,beta-methyleneATP (alpha,beta,meATPadenosine 5'-diphosphate (ADP)uridine 5'-triphosphate (UTP)adenosine 5'-monophosphate (AMP)=adenosine (Ad). 5. Pretreatment with forskolin (10 microM), 8-bromoadenosine-3',5'-cyclophosphate (8-Br-cyclic AMP, 1 mM), 3-isobutyl-1-methylxanthine (IBMX, 1 mM) or phorbol-12-myristate-13-acetate (PMA, 1 microM) reversibly reduced the ATP-induced peak current. 6. The results are consistent with molecular biological data which indicate that P2X2 purinoceptors are present in Deiters' cells. In addition, the reduction of the ATP-gated current by activators of protein kinase A and protein kinase C indicates that these P2X2 purinoceptors can be functionally modulated by receptor phosphorylation. |
| Databáze: | OpenAIRE |
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