Effects of prostaglandin and noradrenalin on sleep-related neurons in the preoptic area.

电刺激蓝斑和延髓腹外侧的去甲肾上腺素能细胞抑制大鼠视前区睡眠活跃神经元和兴奋清醒活跃神经元。通过多管微移管施加去甲肾上腺素也抑制睡眠活跃神经元和兴奋的清醒活跃神经元。肾上腺素能受体拮抗剂和激动剂的应用表明，抑制作用是由alpha_2介导的，而兴奋作用是由alpha_1受体介导的。在清醒状态下，前列腺素d2 （PGD_2）激活睡眠活跃神经元，抑制清醒活跃神经元。连续应用PGD_2可减弱清醒时神经元的活动。然而，PGD_2在睡眠期间引起反应的效果较差。PGD_2还能减弱去甲肾上腺素诱导的睡眠相关神经元的反应。这些结果表明：(1)去甲肾上腺素通过α _2受体抑制睡眠活跃神经元并通过α _1受体刺激清醒活跃神经元促进觉醒；(2)PGD_2通过刺激睡眠活跃神经元和抑制清醒活跃神经元促进睡眠；(3)PGD_2最重要的作用是减弱清醒时的活动；(4)PGD_2减弱去甲肾上腺素介导的觉醒影响。

Electrical stimulation of noradrenergic cells in the locus coeruleus and ventrolateral medulla inhibited sleep-active neurons and excited waking-active neurons in the preoptic area of the rat. Noradrenaline applied through a multibarrel micropipette also inhibited sleep-active neurons and excited waking-active neurons. Application of antagonists and agonists for adrenoceptors revealed that inhibition was mediated by alpha_2-and excitation by alpha_1-receptors.During wakefulness, prostaglandin D_2 (PGD_2) excited sleep-active neurons and inhibited waking-active neurons. Continuous application of PGD_2 attenuated neuron activity during wakefulness. However, PGD_2 was less effective in eliciting a response during sleep. PGD_2 also attenuated noradrenaline-induced responses of sleep-related neurons.These results suggest (1) noradrenaline promotes wakefulness by inhibiting sleep-active neurons through alpha_2-receptors and by exciting waking-active neurons through alpha_1-receptors, (2) PGD_2 promotes sleep by exciting sleep-active neurons and by inhibiting waking-active neurons, (3) most important action of PGD_2 is the attenuation of activity during wakefulness, and (4) PGD_2 attenuates the noradrenaline-mediated arousal influence.