Defensive behaviors evoked from the ventrolateral periaqueductal gray of the rat: Comparison of opioid and GABA disinhibition
Defensive behaviors evoked from the ventrolateral periaqueductal gray of the rat: Comparison of opioid and GABA disinhibition
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DOI：
10.1016/j.bbr.2005.05.009
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发表时间：
2005-10-14
影响因子：
2.7
通讯作者：
Clayton, CC
中科院分区：
文献类型：
--
作者：
Morgan, MM;Clayton, CC
将吗啡显微注射到腹外侧导水管周围灰质 (PAG) 会抑制输出神经元，从而导致不动和镇痛。显微注射 GABA 拮抗剂荷包牡丹碱也可产生去抑制作用。如果吗啡和荷包牡丹碱抑制同一类神经元，那么引起的行为效应应该是相同的。将吗啡（5μg/0.4μl）显微注射到 PAG 腹外侧，85 只大鼠中的 46 只（54%）产生了镇痛作用。随后将荷包牡丹碱（2.5、5、10和25ng/0.4μl）注射到相同的PAG位点，使用或不使用吗啡镇痛的大鼠亚组。荷包牡丹碱的显微注射导致热板潜伏期的增加，这与先前吗啡显微注射的效果无关。服用荷包牡丹碱还可以增加大多数大鼠的运动能力，而不是像吗啡微量注射那样使大鼠无法活动。吗啡和荷包牡丹碱显微注射之间的这些差异表明三件事：（a）无论是吗啡还是荷包牡丹碱对 PAG 神经元的去抑制都是产生镇痛的有效方法； (b) 吗啡和荷包牡丹碱的行为效应背后的电路不同； (c) 腹外侧 PAG 似乎能够支持从不动到飞行的一系列防御行为。 (c) 2005 年 Elsevier B.V. 出版
Microinjection of morphine into the ventrolateral periaqueductal gray (PAG) disinhibits output neurons resulting in immobility and antinociception. Disinhibition also can be produced by microinjection of the GABA antagonist bicuculline. If morphine and bicuculline disinhibit the same class of neurons, then the behavioral effects evoked should be the same. Microinjection of morphine (5 mu g/0.4 mu l) into the ventrolateral PAG produced antinociception in 46 of 85 rats (54%). Subsets of rats with and without morphine antinociception were subsequently injected with bicuculline (2.5, 5, 10, and 25 ng/0.4 mu l) into the same PAG site. Microinjection of bicuculline produced an increase in hot plate latency that was independent of the effect of the prior morphine microinjection. Bicuculline administration also produced an increase in locomotor activity in most rats, not immobility as with morphine microinjections. These differences between morphine and bicuculline microinjections indicate three things: (a) disinhibition of PAG neurons whether by morphine or bicuculline is an effective means of producing antinociception; (b) the circuitry underlying the behavioral effects of morphine and bicuculline differ; (c) the ventrolateral PAG appears capable of supporting a range of defensive behaviors from immobility to flight. (c) 2005 Published by Elsevier B.V.