FIG. 5.

Treatment with VPA for the entire recovery period causes decreased numbers of regenerated hair cells. Chick utricles (n = 20) were placed in culture and treated for 24 h with 1 mM streptomycin. They were then rinsed and maintained in vitro for an additional 8 days. Some cultures (n = 10) also received 1 mM VPA for the entire recovery period. Following fixation, hair cells were labeled with the HCS-1 antibody and quantified from randomly selected 10,000-μm² portions of the extrastriolar regions. Normal hair cell recovery was observed in untreated utricles (A). Treatment with VPA for the entire regenerative period resulted in a 55% reduction in HCS-1-labeled cells (B, C). Error bars standard deviation, scale bar 25 μm, *p < 0.001.