OBJECTIVE: The purpose of the present study was to investigate the effect of dopamine as a possible regulator of epithelial Na(+) channel (ENaC) in the Reissner's membrane (RM). METHODS: RM was freshly dissected from the gerbil cochlea, and short-circuit current (Isc) was measured using the voltage-sensitive vibrating probe technique. The dopamine receptor expression was examined using immunohistochemistry. RESULTS: The results showed that dopamine induced activation of the amiloride-sensitive Isc, but not after pre-treatment with amiloride. The D1-like receptor antagonist SCH-23390, but not the D2-like receptor antagonist sulpiride, decreased the stimulatory effect of dopamine on RM. The effect of dopamine on Na(+) transport via ENaC was still observed after blockade of the Na(+)-K(+)-ATPase by ouabain. D1 receptor immunoreactivity was observed in RM, stria vascularis and spiral ganglion. CONCLUSION: Na(+) transport in RM is activated by dopamine possibly via D1-like receptors, and intracellular mechanisms other than cAMP-mediated pathway may be involved.
OBJECTIVE: The purpose of the present study was to investigate the effect of dopamine as a possible regulator of epithelial Na(+) channel (ENaC) in the Reissner's membrane (RM). METHODS: RM was freshly dissected from the gerbil cochlea, and short-circuit current (Isc) was measured using the voltage-sensitive vibrating probe technique. The dopamine receptor expression was examined using immunohistochemistry. RESULTS: The results showed that dopamine induced activation of the amiloride-sensitive Isc, but not after pre-treatment with amiloride. The D1-like receptor antagonist SCH-23390, but not the D2-like receptor antagonist sulpiride, decreased the stimulatory effect of dopamine on RM. The effect of dopamine on Na(+) transport via ENaC was still observed after blockade of the Na(+)-K(+)-ATPase by ouabain. D1 receptor immunoreactivity was observed in RM, stria vascularis and spiral ganglion. CONCLUSION: Na(+) transport in RM is activated by dopamine possibly via D1-like receptors, and intracellular mechanisms other than cAMP-mediated pathway may be involved.
Authors: Bo Gyung Kim; Jin Young Kim; JinSei Jung; In Seok Moon; Joo-Heon Yoon; Jae Young Choi; Sung Huhn Kim Journal: Sci Rep Date: 2017-02-06 Impact factor: 4.379