PDE6B and retinitis pigmentosa 1: Similarly, a study carried out in two mouse models of autosomal recessive RP, the rd1 and rd10 mouse models, showed that daily injections for 12 days of VPA in rd1 mice resulted in a significant increase in photoreceptor rows, with several extra rows of rod nuclei compared to PBS injected controls (Mitton et al., 2014).