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Nitric oxide/Cyclic GMP pathway attenuates ATP‐evoked intracellular calcium increase in supporting cells of the guinea pig cochlea
Author(s) -
Matsunobu Takeshi,
Schacht Jochen
Publication year - 2000
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/1096-9861(20000731)423:3<452::aid-cne8>3.0.co;2-y
Subject(s) - cgmp dependent protein kinase , nitric oxide , sodium nitroprusside , calcium , soluble guanylyl cyclase , calcium in biology , microbiology and biotechnology , biology , intracellular , cochlea , protein kinase a , nitric oxide synthase , biochemistry , chemistry , kinase , cyclic gmp , endocrinology , anatomy , mitogen activated protein kinase kinase , organic chemistry
Abstract We demonstrate here that nitric oxide (NO) attenuates ATP‐evoked calcium transients in Deiters' and Hensen's cells, “supporting” (nonsensory) cells of the guinea pig cochlea, by means of activation of soluble guanylyl cyclase and protein kinase G. The enzymatic activities associated with the nitric oxide/cGMP/protein kinase G pathway had previously been demonstrated to be present in Deiters' and Hensen's cells. We now isolate these cells and measure changes in intracellular free calcium by using the calcium indicator fluo‐3. In Deiters' cells, calcium increased rapidly in response to the application of ATP. The increase was attenuated when the pathway was stimulated by NO donors (diethylamine NONOate or sodium nitroprusside) or the cyclic GMP analog, 8‐bromo‐cyclic GMP. When the activation of the pathway was blocked by the additional presence of inhibitors of soluble guanylyl cyclase (LY83583) or protein kinase G (Rp‐8‐bromo‐cyclic GMP or KT5823), the response to ATP was restored. The reactions also occurred in calcium‐free media. Hensen's cells responded similarly. These results provide evidence that intracellular calcium is regulated by the NO/cGMP/protein kinase G pathway in the inner ear. J. Comp. Neurol. 423:452–461, 2000. © 2000 Wiley‐Liss, Inc.