The effects of several vasopressin receptor antagonists on normal intraocular pressure and the intraocular distribution of vasopressin receptor subtypes.

The aim of the present paper is to study the relation between vasopressin antagonism and the regulation of intraocular pressure (IOP). From the studies on the effect of several vasopressin receptor antagonists, VP-343, OPC-21268, YM087, OPC-31260 and SR121463, on normal IOP and the effect of VP-343 on pupil diameter in rabbit, it was shown that some vasopressin antagonists decreased normal IOP and VP-343 had no influence on pupil diameter. A vasopressin receptor mapping study in normal cynomolgus monkey eye revealed a high density binding site for a [H3]vasopressin V1 antagonist in the region of iris. These findings suggest that a vasopressin antagonist should decrease normal IOP without miosis and that vasopressin V1 receptors are present in iris.