Morphology Alterations of Synapses in the Ventromedial Nucleus (VM) of Thalamus and Caudal Nucleus Tractus Solitarius (NTS) after 10 Hz Electroacupuncture in Rats

電針刺激安眠穴改變視丘腹內側神經核及孤獨徑核內之突觸型態

鄭穹翔(Chiung-Hsiang Cheng) ； 尹珮璐(Pei-Lu Yi) ； 張涵涵(Han-Han Chang) ； 張芳嘉(Fang-Chia Chang)

《臺灣獸醫學雜誌》 38卷2期 (2012/06) Pp. 75-83

https://doi.org/10.7009/TVJ.201206.0075

摘要

先前實驗發現在暗期給予10 Hz的電針刺激安眠穴會增加慢波睡眠期（slow wave sleep; SWS）。產生的原因和增加孤獨徑核（nucleus tractus solitarius; NTS）的乙醯膽鹼活性以及下游的嗎啡類受體有關。解剖上，從NTS來的神經投射到parabrachial nuclei （PBN），再投射到視丘的腹內側神經核 （ventromedial nucleus of the thalamus; VM）；或直接由NTS投射到視丘的腹內側神經核。清醒時腦中皮質的神經突觸活性較強，但在睡眠時的神經活動基本上會減少這些突觸的活性。從NTS到PBN以及VM的嗎啡類神經藉由嗎啡類受體過極化了PBN以及VM中的神經。因此我們之前假設10 Hz電針刺激增加NTS的突觸活性，造成PBN以及VM的過極化，導致增加睡眠的現象。本論文的研究著重在10 Hz電針刺激安眠穴後，NTS和VM 的突觸密度和長度的改變。我們發現10 Hz電針刺激安眠穴後NTS和VM的突觸密度都有增加，但是突觸總長度只有在NTS部位有顯著改變。這實驗結果可能代表了電針刺激會增加興奮性突觸的長度以及密度來增強NTS的突觸強度，並且在VM增加抑制性突觸的密度來減低VM的突觸強度，並藉此達到電針安眠穴增加睡眠的作用。

關鍵字

孤獨徑核 ； 電針刺激 ； 突觸型態 ； 視丘腹內側神經核

並列摘要

Previous results demonstrated that 10 Hz electroacupuncture (EA) of Anmian acupoints in rats during the dark period enhances slow wave sleep (SWS), which involves the induction of cholinergic activity in the caudal nucleus tractus solitarius (NTS) and subsequent activation of opioidergic neurons and μ-receptors. One ascending projection is from NTS to the ventromedial nucleus (VM) of the thalamus (the NTS-VM pathway). Wakefulness is accompanied by synaptic potentiation in the cortical circuits, whereas slow wave activity (SWA) during SWS promotes a generalized depression or downscaling of synaptic strength. The VM receives opioidergic inputs from NTS and the activation of opioid receptors hyperpolarizes neurons of VM. Accordingly, 10 Hz EA may increase synaptic activity of NTS and subsequently hyperpolarize and downscale the synaptic strength in the VM of thalamus by inhibitory afferents, which lead to enhance SWS. Enhancement of excitatory synapses in NTS and inhibitory synapses in VM may respectively contribute to the up-regulation of synaptic strength in NTS and downscaling of synaptic strength in the VM after 10 Hz EA. Our results demonstrated that the synaptic density was increased in both NTS and VM after rats received 10 Hz EA stimuli, while the enhanced synaptic length was only observed in the NTS, suggesting that 10 Hz EA altered excitatory synaptic strength of NTS and inhibitory synaptic strength of VM by changing the synaptic morphology.

並列關鍵字

electroacupuncture ； nucleus tractus solitarius (NTS) ； synaptic morphology ； ventromedial nucleus of thalamus