Expression and localization of endothelin-1 and its receptors in the spiral ganglion neurons of mouse

Abstract

Endothelin-1 (ET-1) is a peptide with various biological functions, such as vasoconstriction and cell proliferation. ET-1 was reported to be widely distributed throughout the animal body, including nervous system. The expression and localization of ET-1 and its receptors [endothelin type-A receptor (ETAR) and endothelin type-B receptor (ETBR)] in the spiral ganglion neurons have not been reported before. In this study, their presence in the mouse spiral ganglion neurons was detected at mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) technique and immunohistochemistry, respectively. RT-PCR analysis indicated that ET-1, ETAR, and ETBR genes were expressed in the mouse spiral ganglion tissues. Immunohistochemical experiments demonstrated that ET-1 and ETAR were predominantly immunoreactive in the cytoplasm, while ETBR was mainly immunostained in the nucleus of the neuron bodies. The present results suggest that ET-1 may play physiological roles in the spiral ganglion cells via ETAR and ETBR.

Fig. 1

Ethidium bromide staining of PCR products on a 2% agarose gel from spiral ganglion tissue of mouse cochlea. Total RNA preparations from spiral ganglion after reverse transcription were subjected to 45 cycles of PCR. Amplification of ET-1, ETAR, ETBR, and GAPDH cDNA is a fragment of 147 bp (a), 137 bp (b), 128 bp (c) and 143 bp (d), respectively (lane 1). PCR products from kidney were used as positive control (lane 2). Lane 3 showed the negative control. M indicates the marker

Fig. 2

Immunostaining of ET-1, ETAR, and ETBR in the spiral ganglion of mouse cochlea. a ET-1 immunoreactivity was mainly detected in the cytoplasm of spiral ganglion neurons. b ETAR immunoreactivity was mainly detected in the cytoplasm of spiral ganglion neurons. c ETBR was predominantly immunostained in the nucleus of the spiral ganglion neurons. d The negative control using PBS instead of specific primary antibodies. No immunoreactivity was observed. Pictures taken at magnification of ×200