The failure of ventricular sodium to control sodium appetite in the rat.

Dilution of CSF sodium by infusion of hyperosmotic mannitol into the cerebral ventricles of the rat does not evoke a salt appetite, nor does the addition of sodium to the CSF of the rat suppress the preexisting salt appetites produced by the hormones of sodium conservation or by adrenalectomy. CSF sodium concentration does not control sodium appetite in the rat. The proposal that it does so in sheep should not be generalized to other species without caution.