[Regulation of Na, K-ATPase activity in the rat brain by noradrenaline]

Effect of noradrenaline on activity of Na, K-ATPase from heavy microsomes of rat brain was studied in vitro; the effect of noradrenaline was shown to be dose dependent. The maximal activation of the enzyme was observed at 5.10(-5) M concentration of the catecholamine; an increase of its concentration above 5.10(-4) M inhibited Na, K-ATPase. beta-Adrenolytic drug propranolol /1.10(-5) M/ did not affect the noradrenaline action. At the same time, an alpha-adrenolytic drug phentholamine /1.10(-5) M/ decreased down to zero the activating effect of the catecholamine, but did not affect the inhibitory effect of noradrenaline at high concentrations /1.10(-3) M/. Effects of selective alpha-adrenomimetic compound phenylephrine were also studied. The data obtained suggest that the activating effect of noradrenaline on Na, K-ATPase from rat brain is mediated through alpha-adrenoreceptors.