ARE THE DOPAMINERGIC CELLS OF THE LAMPREY RETINA INTERPLEXIFORM CELLS- A DOPAMINE, TYROSINE-HYDROXYLASE AND DOPAMINE-BETA-HYDROXYLASE IMMUNOCYTOCHEMICAL STUDY

The distribution of dopaminergic cells in the retina of sea lamprey Pe tromyzon marinus L. was studied with antisera against dopamine and tyr osine hydroxylase. Both antisera consistently labelled cells and proce sses located in the inner nuclear and inner plexiform layers. No dopam ine-immunoreactive processes were observed in the external retina. The ellipsoids of photoreceptors and small bodies close to the external l imiting membrane were also labelled with the tyrosine hydroxylase anti serum. It is concluded that the dopaminergic cells of the lamprey reti na are amacrine cells. In addition, the presence of dopamine-beta-hydr oxylase-like-immunoreactive fibres of central origin is reported for t he first time.