Subunits of voltage-gated calcium channels in murine spiral ganglion cells.

CONCLUSION

The results show that alpha1D, alpha1E, alpha2/delta, beta1, and beta3 subunits are expressed in spiral ganglion cells (SGCs), and the coexpression of alpha1D and alpha1E suggests the presence of L-type and R-type calcium channels in mammalian SGCs.

OBJECTIVE

To investigate the types of subunits of voltage-gated calcium channels in SGCs of the mouse.

MATERIALS AND METHODS

SGCs were isolated from cochleae of neonatal mice and cultured for 24 h. Total RNA was extracted from cultured cells. After reverse transcription, the resulting cDNA was amplified by PCR with primers targeted to nucleotide sequences corresponding to seven different calcium channel subunits. The types of calcium channel subunits were identified by PCR analysis and nucleotide sequencing.

RESULTS

RT-PCR showed the strong and consistent amplification of alpha1D, alpha1E, alpha2/delta, beta1, and beta3 subunits from the mRNA of SGCs, and nucleotide sequencing confirmed the identity of mouse cochlear subunit cDNAs.