O'Neill T P, Haigler H J
J Pharmacol Exp Ther. 1982 Sep;222(3):555-61.
Norepinephrine (NE) may be a neurotransmitter in a nociceptive pathway in the mesencephalic reticular formation (MRF) of the rat. When NE is applied microiontophoretically to certain neurons in rat MRF, it produces a change in neuronal firing rate similar to that produced by a noxious stimulus (foot pinch) in these neurons. If NE is a neurotransmitter involved in the transmission of nociceptive information in the MRF, specific adrenergic receptor antagonists, administered microiontophoretically, should block both the firing evoked by NE, administered microiontophoretically, and the firing evoked by foot pinch in these neurons. When phentolamine (an alpha adrenoceptor antagonist) was administered microiontophoretically it blocked the increases in neuronal firing rate evoked either by foot pinch or by NE. In contrast, propranolol (a beta adrenoceptor antagonist) rarely blocked the firing evoked by either foot pinch or by the microiontophoretic administration of NE. Thus, it appears that if NE is involved in the transmission of nociceptive information in the MRF of the rat, this information transfer is mediated by alpha adrenergic receptors.
去甲肾上腺素（NE）可能是大鼠中脑网状结构（MRF）伤害性感受通路中的一种神经递质。当通过微离子透入法将NE施加于大鼠MRF的某些神经元时，它会使神经元放电频率发生变化，类似于这些神经元受到伤害性刺激（夹足）时所产生的变化。如果NE是参与MRF中伤害性信息传递的神经递质，那么通过微离子透入法给予特定的肾上腺素能受体拮抗剂，应该能够阻断由微离子透入法给予NE所诱发的放电，以及这些神经元中夹足所诱发的放电。当通过微离子透入法给予酚妥拉明（一种α肾上腺素能受体拮抗剂）时，它阻断了夹足或NE所诱发的神经元放电频率增加。相比之下，普萘洛尔（一种β肾上腺素能受体拮抗剂）很少能阻断夹足或微离子透入法给予NE所诱发的放电。因此，似乎如果NE参与大鼠MRF中伤害性信息的传递，那么这种信息传递是由α肾上腺素能受体介导的。
