Alpha-MPT does not affect dopamine levels in the periventricular organ of lizards.

Recent studies indicate that the liquor (CSF)-contacting cell bodies in the periventricular organ of non-mammalian vertebrates accumulates rather than synthesizes dopamine. We therefore gave the lizard Gekko gecko injections of the dopamine synthesis inhibitor alpha-methylparatyrosine (alpha-MPT). Brains were fixed 105-240 min after injection. Subsequent staining with dopamine antiserum revealed almost no changes in staining in the periventricular organ but there was a dramatic decrease in the other dopaminergic cell groups of the brain. The data support the notion that the cells in the periventricular organ accumulate dopamine and that the CSF plays an important role in dopamine neurotransmission in non-mammalian vertebrates.