  We report on the results of a search using the VLA for redshifted HCN(1-0)
emission from the host galaxy of BR B1202-0725, an optically luminous quasar at
z=4.695. The host galaxy emits strongly in the rest-frame far-infrared, and
shows characteristics very similar to that of more local, ultraluminous
infrared galaxies, in which a significant fraction of the far-infrared emission
is powered by star formation. We find a 3-sigma upper limit to the HCN(1-0)
emission of 4.9 x 10^10 K kms^-1 pc^2, assuming a lambda-cosmology. This limit
is consistent with correlations derived from measurements of the HCN, CO, and
far-infrared emission for a sample of more local galaxies, including starbursts
(Solomon et al, 1992a).
