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P2X receptors in cochlear Deiters' cells
1Kresge Hearing Research Laboratory of the South, Department of Otorhinolaryngology and Biocommunication, Louisiana State University Medical Center, New Orleans 70112-2234, USA.
British Journal of Pharmacology
|June 26, 1998
Summary
This study characterizes ionotropic purinoceptors in guinea-pig cochlear Deiters
Area of Science:
- Neuroscience
- Otolaryngology
- Cell Biology
Background:
- Deiters' cells in the cochlea play a crucial role in auditory function.
- Ionotropic purinoceptors are involved in cellular signaling pathways within the auditory system.
Purpose of the Study:
- To characterize the ionotropic purinoceptors in isolated Deiters' cells from the guinea-pig cochlea.
- To investigate the functional properties and modulation of these purinoceptors.
Main Methods:
- Whole-cell patch-clamp technique was employed to record currents in isolated Deiters' cells.
- Extracellular application of various purinergic agonists, including adenosine 5'-triphosphate (ATP), was used to stimulate the cells.
- Intracellular calcium levels and the effects of protein kinase activators were manipulated.
Main Results:
- Extracellular ATP induced a dose-dependent inward current with desensitization and a reversal potential around -4 mV.
- Increased intracellular free Ca2+ reduced the amplitude of the ATP-gated current.
- The potency order for agonists was 2-methylthioATP > ATP > BzATP > α,β-methyleneATP > ADP > UTP > AMP = Adenosine.
- Forskolin, 8-Br-cyclic AMP, IBMX, and PMA reversibly reduced the ATP-induced peak current, indicating modulation by protein kinase A and C pathways.
Conclusions:
- The findings support the presence of P2X2 purinoceptors in Deiters' cells.
- These P2X2 purinoceptors are subject to functional modulation via phosphorylation by protein kinase A and C.