A method to deliver morpholinos directly into the zebrafish otocyst at 24hpf has been developed. Using microinjection of morpholinos into the lumen of otic vesicle and electroporation to effect penetration, we were able to bypass the effect of morpholinos on the brain and obtain effects specific to the inner ear.
Holmes, K. E., Wyatt, M. J., Shen, Y., Thompson, D. A., Barald, K. F. Direct Delivery of MIF Morpholinos Into the Zebrafish Otocyst by Injection and Electroporation Affects Inner Ear Development. J. Vis. Exp. (47), e2466, doi:10.3791/2466 (2011).