Perez S E, Silveira J E, Silva-Netto C R
Departamento de Ciências da Saúde, Universidade Federal de São Carlos, SP, Brasil.
Braz J Med Biol Res. 1990;23(12):1343-8.
Injection of Met-enkephalin (0.05, 0.25 and 0.50 micrograms in 1 microliter) solutions into the lateral hypothalamic area (LHA) of unrestrained and unanesthetized rats caused a significant decrease of sodium (0.39 +/- 0.13 to 0.07 +/- 0.01, P less than 0.05) and potassium (0.61 +/- 0.17 to 0.21 +/- 0.04, P less than 0.05) excretion. When the blocking agent naloxone (0.20 micrograms in 1 microliter) was injected alone, a significant increase of sodium (0.34 +/- 0.04 to 0.96 +/- 0.28, P less than 0.05) and potassium (0.76 +/- 0.13 to 1.72 +/- 0.30, P less than 0.05) excretion was observed. However, a dose-response relationship was not observed. However, when in another experiment naloxone was injected before Met-enkephalin into the same area, reversal of the effect of naloxone occurred, with decreased sodium and potassium excretion. We conclude that the enkephalinergic pathway of the LHA when stimulated with Met-enkephalin plays an inhibitory role in the control of sodium and potassium excretion.
将甲硫氨酸脑啡肽溶液（1微升含0.05、0.25和0.50微克）注射到未束缚、未麻醉大鼠的下丘脑外侧区（LHA），可导致钠排泄量显著减少（从0.39±0.13降至0.07±0.01，P<0.05）以及钾排泄量显著减少（从0.61±0.17降至0.21±0.04，P<0.05）。当单独注射阻断剂纳洛酮（1微升含0.20微克）时，观察到钠排泄量显著增加（从0.34±0.04增至0.96±0.28，P<0.05）以及钾排泄量显著增加（从0.76±0.13增至1.72±0.30，P<0.05）。然而，未观察到剂量反应关系。不过，在另一项实验中，当在注射甲硫氨酸脑啡肽之前将纳洛酮注射到同一区域时，出现了纳洛酮效应的逆转，钠和钾排泄量减少。我们得出结论，当下丘脑外侧区的脑啡肽能通路被甲硫氨酸脑啡肽刺激时，在钠和钾排泄的控制中起抑制作用。
