Rolipram and BDNF application induced the activation of ERK and CREB.

<p>Immunofluorescence staining of activated ERK (pERK; A–D) and activated CREB (pCREB; E–H) in spiral ganglion cell cultures incubated in medium for 48 h (A, E) or exposed to Rolipram (R; B, F) or BDNF (C, G) for 30 min after a pre-incubation of (47 h, 30 min) in medium. D, H shows the pERK and pCREB immunoreactivity in cells pre-treated with BDNF (47 h, 30 min) and additionally exposed to Rolipram for 30 min (D, H). Photographs were taken under the same conditions in which exposure time and intensity was adjusted to the untreated control group (A, E). Application of Rolipram (B, F) or BDNF (C, G) induced the activation of ERK and CREB. Stronger pERK and pCREB immunoreactivity was observed after co-treatment with Rolipram and BDNF (D, H). BDNF: brain-derived neurotrophic factor; R: Rolipram. Scale bar: 50 μm (A–H).