title: Barrier mechanisms for neutrotransmitter monoamines in the choroid plexus.
abstract: Studies were performed on choroid plexuses from mouse and rat. The plexus tissue, sympathectomized to avoid interference from adrenergic nerves, is able to accumulate L-DOPA as well as NA and 5-HT against a concentration gradient. Within the plexus tissue these compounds are metabolized by aromatic L-amino acid decarboxylase, MAO and COMT, whose activities were determined radiometrically. On the basis of this and the fate of systemically administered L-DOPA and DA studied by fluorescence histochemistry it is suggested that the epithelium of the choroid plexus provides not only a structural but also an enzymatic barrier for transmitter amines. The enzymatic barrier for amine precursors is considerably less sufficient at this blood-CSF interphase. The trapping of monoamines resembles the enzymatic barrier present in the endothelial cells and pericytes at the microvascular level of the blood-brain interphase.
mesh_terms: D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000378:metabolism*; D001812:Blood-Brain Barrier; D002394:Catechol O-Methyltransferase / Q000378:metabolism*; D002831:Choroid Plexus / Q000201:enzymology*; D005260:Female; D066298:In Vitro Techniques; D007980:Levodopa / Q000378:metabolism; D008297:Male; D051379:Mice; D008995:Monoamine Oxidase / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D012701:Serotonin; D007980:Levodopa; D008995:Monoamine Oxidase; D002394:Catechol O-Methyltransferase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D009638:Norepinephrine