Role of Dopaminergic Receptors in Glaucomatous Disease Modulation

Both studies on animals and humans suggest the presence of dopamine (DA) receptors in the anterior segment of the eye. Their role in the dynamics of intraocular pressure (IOP) is not yet clear. DA(2) and DA(3) receptors are mainly located on postganglionic sympathetic nerve endings. Their stimulation reduces the release of norepinephrine and suppresses the production of aqueous humor. DA(1) receptors seem to be more expressed by the ciliary body and the outflow pathway of aqueous humor. The administration of DA(1)-selective agonists stimulates the production of aqueous humor, increasing IOP, whereas DA(2)- and DA(3)-selective agonists could reduce IOP and, therefore, the risk to develop a glaucoma (GL). GL is a broad spectrum of eye diseases which have in common the damage to the optic nerve and the progressive loss of the visual field. Further studies are desirable to clarify the role of the dopaminergic system and the usefulness of DA(2) and DA(3) agonists in reducing IOP.