Characterization of the in vitro uptake of monoamines into brain microvessels.
The ability of brain microvessels to take up and metabolize transmitter monoamines (DA, NA, A and 5-HT) was studied in tissues from several species (rat, guinea-pig, cat, dog, baboon, man) in vitro. Following incubation, slices were analyzed by fluorescence histochemistry and isolated microvessels by measurement of radioactivity from tritiated amine. Provided the MAO activity was inhibited a strong accumulation, similar for all animals tested, occurred in the wall (endothelial cells and pericytes) of capillaries and venules--but not in larger vessels--of all species. The degree of amine uptake and accumulation and the conditions under which it was inhibited suggested that it reflected a saturable, energy-dependent process, with characteristics of both the extraneuronal and neuronal type of uptake processes. The mechanism may serve as an inactivation of transmitter monoamines at the blood-brain interphase, thereby assisting in the control of transmitter levels in the cerebral extracellular compartment.
D000818:Animals; D001921:Brain / Q000098:blood supply*; D002415:Cats; D004285:Dogs; D004298:Dopamine / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006168:Guinea Pigs; D000882:Haplorhini; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008833:Microcirculation; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D010215:Papio; D011817:Rabbits; D051381:Rats; D012701:Serotonin / Q000378:metabolism
D018377:Neurotransmitter Agents; D012701:Serotonin; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine