Retinal dopaminergic receptor affinity and ocular pharmacokinetic profile of piribedil.
Binding studies on retinal dopamine receptors have revealed the existence of both D1 and D2 receptors. Human retina micro-autoradiographs confirm the distribution of dopaminergic receptors in the plexiform layers. Piribedil, a dopaminergic agonist, is able to bind to D2 receptors, while its metabolite (S584) preferentially displaces D1-specific radioligands. These results demonstrate that piribedil has a dopamine-like pharmacological profile including direct interaction with receptors. When instilled into the rabbit eye, piribedil penetrates rapidly and accumulates in the pigmented epithelia--the iris ciliary body and chorioretina--before being rapidly cleared. Macro-autoradiographs confirm this distribution and show the levels to be compatible with the affinity of piribedil for retinal dopaminergic receptors.
Lapalus
P
P
Department of Experimental and Clinical Pharmacology, Faculté de Médecine, Nice, France.
Denis
P
P
Drici
M
M
Fredj-Reygrobellet
D
D
Elena
P P
PP
D000818:Animals; D001345:Autoradiography; D006801:Humans; D010891:Piribedil / Q000493:pharmacokinetics*; D011817:Rabbits; D011954:Receptors, Dopamine / Q000378:metabolism*; D012160:Retina / Q000378:metabolism*
D011954:Receptors, Dopamine; D010891:Piribedil