Abercrombie E D, Levine E S, Jacobs B L
Department of Psychology, Princton University, NJ 08544.
Neurosci Lett. 1988 Apr 12;86(3):334-9. doi: 10.1016/0304-3940(88)90506-x.
Microinjection of morphine (1.0 microgram/0.1 microliter) produced a significant suppression (approximately 60%) of the single unit activity of locus coeruleus noradrenergic neurons in freely moving cats. This effect was reversible by systemic administration of the opioid receptor antagonist, naloxone (1.0 mg/kg i.v.). The microinjection of naloxone (1.0 microgram/0.1 microliter), however, was without effect on the spontaneous activity of noradrenergic neurons in the locus coeruleus. Non-noradrenergic neurons recorded in the same vicinity showed no consistent response to the microinjection of morphine. These results suggest that the direct effect of opioids in the locus coeruleus is an inhibition of noradrenergic neuronal activity. Furthermore, it appears that opioid influences upon these neurons are not tonically active.
向自由活动的猫脑桥蓝斑核去甲肾上腺素能神经元微量注射吗啡（1.0微克/0.1微升）可显著抑制其单位活动（约60%）。静脉注射阿片受体拮抗剂纳洛酮（1.0毫克/千克）可使该效应逆转。然而，向蓝斑核微量注射纳洛酮（1.0微克/0.1微升）对去甲肾上腺素能神经元的自发活动无影响。在同一区域记录的非去甲肾上腺素能神经元对微量注射吗啡无一致反应。这些结果表明，阿片类物质在蓝斑核的直接作用是抑制去甲肾上腺素能神经元活动。此外，阿片类物质对这些神经元的影响似乎并非持续活跃。
