Li J, Hand G A, Potts J T, Mitchell J H
Department of Internal Medicine and Moss Heart Center, University of Texas Southwestern Medical Center, Dallas 75235-9034, USA.
Brain Res. 1997 Mar 28;752(1-2):45-51. doi: 10.1016/s0006-8993(96)01443-6.
Blood pressure and heart rate reflexly increase during static muscle contraction in anesthetized cats. Previous studies have demonstrated that vasopressin (AVP) and oxytocin (OT) may act as neuromodulators to regulate cardiovascular responses elicited by contraction of skeletal muscle. In this study, we tested the hypothesis that neurons containing AVP and OT in the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) of the hypothalamus are activated during static muscle contraction. A laminectomy was performed to expose the spinal cord and the peripheral cut ends of L7 and S1 ventral roots were stimulated electrically to induce muscle contraction. Hypothalamic neurons activated during the muscle contraction were identified by Fos-like immunoreactivity (FLI). Static muscle contraction significantly increased FLI in the PVN and SON, compared with sham-operated cats. Double-staining of neurons in the PVN for AVP and OT showed that 22 +/- 4% of the AVP and 26 +/- 3% of the OT neurons in the PVN expressed FLI. In contrast, only 4 +/- 1% of the AVP and 3 +/- 1% of the OT neurons in the PVN were labeled with FLI in sham-operated animals. These results indicate that neurons in the PVN and SON of the hypothalamus were activated during static muscle contraction. Furthermore, as FLI was present in AVP and OT neurons, this suggests these neurons may constitute a part of the neural pathway involved in cardiovascular regulation during static muscle contraction.
在麻醉猫的静态肌肉收缩过程中，血压和心率会反射性升高。先前的研究表明，血管加压素（AVP）和催产素（OT）可能作为神经调节剂来调节骨骼肌收缩引发的心血管反应。在本研究中，我们检验了以下假设：在下丘脑室旁核（PVN）和视上核（SON）中含有AVP和OT的神经元在静态肌肉收缩过程中被激活。进行椎板切除术以暴露脊髓，并对L7和S1腹侧神经根的外周切断端进行电刺激以诱导肌肉收缩。通过Fos样免疫反应性（FLI）来识别在肌肉收缩过程中被激活的下丘脑神经元。与假手术猫相比，静态肌肉收缩显著增加了PVN和SON中的FLI。对PVN中的神经元进行AVP和OT双重染色显示，PVN中22±4%的AVP神经元和26±3%的OT神经元表达FLI。相比之下，在假手术动物中，PVN中只有4±1%的AVP神经元和3±1%的OT神经元被FLI标记。这些结果表明，下丘脑的PVN和SON中的神经元在静态肌肉收缩过程中被激活。此外，由于FLI存在于AVP和OT神经元中，这表明这些神经元可能构成了静态肌肉收缩期间参与心血管调节的神经通路的一部分。
