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Effects of gramine on energy metabolism of rat and bovine mitochondria

1984; Elsevier BV; Volume: 33; Issue: 19 Linguagem: Inglês

10.1016/0006-2952(84)90596-3

1873-2968

Hermann M. Niemeyer, Oscar A. Roveri,

Ion channel regulation and function

The indole alkaloid gramine is found in several plant families. Its effects on mammalian mitochondria and submitochondrial particles were studied. Low concentrations of gramine slightly stimulated basal electron transport, totally inhibited the Ca2+-induced respiratory control and partially abolished the enhancement of 8-anilino-1-naphthalene sulfonate fluorescence induced by proton translocation coupled to ATP hydrolysis or to succinate oxidation. At higher concentrations gramine inhibited specifically the electron transport at the level of Complex I of the respiratory chain. The I50 values (2-6 mM) were dependent on the presence of uncouplers. Higher concentrations of the alkaloid also inhibited coupled succinate oxidation and ATP hydrolysis (I50 = 10 mM). Possible explanations for these effects are discussed.