Dopamine receptors are located on rods in bovine retina

In purified rod outer segments, the dopamine receptor antagonist [3H] spiperone and agonist [3H]N-propyl-norapomorphine densely label sites with the pharmacological profile of dopamine-D2 receptors. In cryostat sections of retina, the region with the highest density of specific labeling by both [3H]spiperone and L-(--)-[N-propyl-3H(N)]propylnorapomorphine is the photoreceptor layer (rod inner and outer segments). These data show that dopamine receptors are primarily associated with photoreceptor rods and provide support for recent evidence which suggests that these receptors modulate photoreceptor function.