Depletion of epinephrine in rat hypothalamus by Ro 4-1284: influence of pargyline and harmaline.
Ro 4-1284, 2-ethyl-2,3,4,6,7,11b-hexahydro-3 isobutyl-9,10-dimethoxy-2H-benzo[a]quinolizin-2-ol hydrochloride, depleted epinephrine in rat hypothalamus; the depletion occurred within 1 hr and persisted at 24 hr. The rapid lowering of epinephrine by Ro 4-1284 was antagonized by pargyline, a monoamine oxidase inhibitor, which alone elevated epinephrine concentration. The ability of pargyline to antagonize epinephrine depletion by Ro 4-1284 was prevented by co-treatment with harmaline, which protects aginst type A but not type B monoamine oxidase inhibition by pargyline. Pargyline also antagonized the Ro 4-1284-induced depletion of norepinephrine in hypothalamus and of norepinephrine and dopamine in cerebral hemispheres, and these effects of pargyline were also prevented by co-treatment with harmaline. The results suggest that epinephrine in rat brain, like norepinephrine and dopamine, is destroyed primarily by type A monoamine oxidase.
D012369:2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-hexahydro-3-isobutyl-9,10-dimethoxy- / Q000494:pharmacology*; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D004837:Epinephrine / Q000378:metabolism*; D006246:Harmaline / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D010293:Pargyline / Q000494:pharmacology*; D011807:Quinolizines / Q000494:pharmacology*; D051381:Rats
D000470:Alkaloids; D011807:Quinolizines; D012369:2H-Benzo(a)quinolizin-2-ol, 2-Ethyl-1,3,4,6,7,11b-hexahydro-3-isobutyl-9,10-dimethoxy-; D010293:Pargyline; D006246:Harmaline; D008995:Monoamine Oxidase; D004837:Epinephrine