Clement C I, Keay K A, Owler B K, Bandler R
Department of Anatomy and Histology, University of Sydney, New South Wales, Australia.
J Comp Neurol. 1996 Mar 11;366(3):495-515. doi: 10.1002/(SICI)1096-9861(19960311)366:3<495::AID-CNE9>3.0.CO;2-#.
Immunohistochemical detection of the protein product (Fos) of the c-fos immediate early gene was used to study neuronal activation in the rostral pons and midbrain of halothane-anesthetised rats following noxious deep somatic or noxious visceral stimulation. In animals exposed only to halothane anesthesia, Fos-like immunoreactive (IR) neurons were located in the midbrain periaqueductal gray matter, tectum, and parabrachial nucleus. Following noxious stimulation of hindlimb muscle, knee joint, vagal cardiopulmonary, or peritoneal nociceptors, there was, compared to halothane-only animals, a significant increase in the numbers of Fos-like (IR) cells in the caudal ventrolateral periaqueductal gray and the intermediate gray lamina of the superior colliculus. Given the general agreement that increased Fos expression is a consequence of increased neuronal activity, the finding that a range of noxious deep somatic and noxious visceral stimuli evoked increased neuronal activity in a discrete, caudal ventrolateral periaqueductal gray region is consistent with previous suggestions that this region is an integrator of deep noxious evoked reactions. The noxious deep somatic and noxious visceral manipulations also evoked, compared to halothane-only animals, reductions in the numbers of Fos-like IR cells in the stratum opticum of the superior colliculus and the unlaminated portion of the external subnucleus of the inferior colliculus. To our knowledge this is the first report of reductions in Fos-expression in the tectum evoked by noxious stimulation. In separate experiments, the effects of noxious deep somatic and noxious visceral manipulations on arterial pressure and heart rate were measured. The noxious visceral manipulations evoked substantial and sustained falls in arterial pressure (15-45 mmHg), and heart rate (75-100 bpm), whereas the depressor and bradycardiac effects of the noxious deep somatic manipulations were weaker, not as sustained, or entirely absent. As similar distributions and numbers of both increased and decreased Fos-like IR cells were observed after each of the deep noxious manipulations, it follows that the deep noxious evoked increases and decreases in Fos expression were not secondary to the evoked depressor or bradycardiac effects.
采用免疫组织化学方法检测即刻早期基因c-fos的蛋白产物（Fos），以研究氟烷麻醉大鼠在深部躯体伤害性刺激或内脏伤害性刺激后，其延髓前部和中脑的神经元激活情况。在仅接受氟烷麻醉的动物中，Fos样免疫反应阳性（IR）神经元位于中脑导水管周围灰质、顶盖和臂旁核。与仅接受氟烷麻醉的动物相比，在后肢肌肉、膝关节、迷走神经心肺或腹膜伤害性感受器受到伤害性刺激后，尾侧腹外侧导水管周围灰质和上丘中间灰质层中Fos样（IR）细胞数量显著增加。鉴于普遍认为Fos表达增加是神经元活动增加的结果，一系列深部躯体伤害性刺激和内脏伤害性刺激在离散的尾侧腹外侧导水管周围灰质区域诱发神经元活动增加，这一发现与之前认为该区域是深部伤害性诱发反应整合器的观点一致。与仅接受氟烷麻醉的动物相比，深部躯体伤害性刺激和内脏伤害性刺激还导致上丘视层和下丘外侧亚核无层部分中Fos样IR细胞数量减少。据我们所知，这是首次报道伤害性刺激诱发顶盖中Fos表达减少。在单独的实验中，测量了深部躯体伤害性刺激和内脏伤害性刺激对动脉血压和心率的影响。内脏伤害性刺激导致动脉血压大幅持续下降（15 - 45 mmHg）和心率下降（75 - 100次/分钟），而深部躯体伤害性刺激的降压和心动过缓效应较弱、持续时间较短或完全没有。由于在每种深部伤害性刺激后观察到Fos样IR细胞增加和减少的分布及数量相似，因此深部伤害性刺激诱发的Fos表达增加和减少并非继发于诱发的降压或心动过缓效应。
