Figure 2.

A–C, RT-PCR (A, C) and qRT-PCR (B) analysis of dopamine receptor expression in wild-type mice. A, D1, D5, and D2 receptors were consistently expressed in OHCs and spiral ganglion neurons (SGNs), but not IHCs harvested from immature cochleas (P11–P13). D4 receptors were expressed only in SGNs. Primers for neurofilament (Nefh), otoferlin, and the nicotinic receptor subunit α10 (Chrna10) were used as markers for SGNs, IHCs, and hair cells, respectively. B, D1, D5, D2, and D4 were expressed in whole adult cochleas, but D3 receptors were never amplified. For the qRT-PCR (B), mean expression levels are normalized to 18S rRNA, after adjusting for primer efficiency, as described previously (Stankovic and Corfas, 2003). Error bars represent SEMs. C, As a positive control for the primers, we showed that all five dopamine receptors are expressed in adult brain. All bands in A and C appear at the expected location (Table 1), as calibrated by the ladder lane: dashed lines are positioned at 100, 200, and 300 base pairs. The 8-bit gel micrographs were adjusted digitally: after inversion, offset was set to 0 by subtracting the mean pixel value from an empty lane; gain was optimized by setting to 256 the mean pixel value from the 500 bp ladder band. Primer bands (<100 bp) are not shown.