• The Korean Journal of Physiology
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• 제27권2호
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• pp.185-197
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• 1993

The rostral ventrolateral medulla (RVLM) includes vasopressor neurons, which transmit activation signals to the intermediolateral nucleus (IML) of the spinal cord, where the preganglionic sympathetic nucleus is located, to raise arterial blood pressure (BP). However, controversy exists as to the possible depressor area in the RVLM and the pathway involved. The present study persued evidence far the location of depressor neurons and the pathway by simultaneously observing changes in BP and the firing rate (FR) of cardiovascular neurons (CVNs) in the RVLM during the somatosympathetic reflex (SSR) elicited by peripheral nerve stimulation, since CVNs are known to contribute to the generation of the sympathetic nerve discharge. In 42 cats, anaesthetized with $\alpha-chloralose$, single unit recording was performed, using carbon filament electrodes inserted into the RVLM, enabling estimation of the post R wave unit histogram (PR-UNlT) and the spike triggered average of sympathetic nerve discharge (STA-SND), allowing identification of CVNs. Antidromic stimulation of spinal $T_2$ segment was followed to determine whether the identified CVN projects axonal endings to the spinal cord (reticulospinal neuron). The sciatic nerve was electrically stimulated at $A\delta-intensity$ (1 mA, 0.1 ms), 1 Hz and C-intensity (10 mA, 0.5 ms), 20 Hz to elicit the depressor, and pressor responses of the SSR, respectively. Simultaneous measurement of CVN firing rate was made. Experimental results are summarized as follows. 1) 20 out of 98 CVNs had axonal projections to the spinal cord and 17 out of 98 CVNs showed FR changes during SSR. 2) Response patterns of FR and BP during SSR were classified into 8 types. 3) These 8 different response patterns could be further classified into those from pressor and depressor neurons. These results demonstrate that some CVNs were identifiable as reticulospinal neurons responding to anti-dromic stimulation and that CVNs operating as depressor neurons as well as pressor neurons exist in the RVLM, both of which are involved with SSR mediation. Therefore, evidence was found that an independent depressor pathway might be involved in the mediation of SSR.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.79-84
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• 1996

A number of experimental evidences suggest that the rnun ventrolateral medulla(RVLM) is the final common pathway in the regulation of arterial blood pressure. A Voup of neurons in the RVLM, called the cardiovascular neurons (UN), show spontaneous activity temporally synchronized with the periodic cardiac cycle. These neurons affect the sympathetic nerve discharge(SND), thus are believed to be responsible for blood pressure control. The present experiment identified 98 UVNs in 42 cats based on the temporal relationships between each neuron's activity with both the cardiac cycle and SWD. In 20 UWL changes of spontaneous firing rate(FR) during the somatosympathetic reflex(SSR) were studied Five different firing patterns were observed during the pressor and depressor responses of SSR, implying that they form an interconnected neuronal circuit interacting with one another to generate efferent signals for blood pressure regulation. In the following companion paper, the firing patterns of CVN are analyzed to develop a minimal neuronal circuit model explaining the present experimental outcome.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.71-80
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• 1996

A number of experimental evidences suggest that the rnun ventrolateral medulla(RVLM) is the final common pathway in the regulation of arterial blood pressure. A Voup of neurons in the RVLM, called the cardiovascular neurons (UN), show spontaneous activity temporally synchronized with the periodic cardiac cycle. These neurons affect the sympathetic nerve discharge(SND), thus are believed to be responsible for blood pressure control. The present experiment identified 98 UVNs in 42 cats based on the temporal relationships between each neuron's activity with both the cardiac cycle and SWD. In 20 UWL changes of spontaneous firing rate(FR) during the somatosympathetic reflex(SSR) were studied Five different firing patterns were observed during the pressor and depressor responses of SSR, implying that they form an interconnected neuronal circuit interacting with one another to generate efferent signals for blood pressure regulation. In the following companion paper, the firing patterns of CVN are analyzed to develop a minimal neuronal circuit model explaining the present experimental outcome.

• 대한약리학회지
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• 제13권2호
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• pp.19-34
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• 1977

1) 마취가토(痲醉家兎) 및 묘(猫)에서 경뇌막외강(硬腦膜外腔)을 통(通)한 가압방법(加壓方法)으로 두개내압상승(頭蓋內驅上昇)과 혈압(血壓) 및 심박(心搏)과의 관계(關係)를 조사(調査)하였다. 2) 양동물(兩動物)에서 두개내압(頭盞內壓)을 상승(上昇)시켜 두개내압(頭蓋內壓)과 혈압(血壓)의 차(差)가 아주 적어지면 현저(顯著)한 혈압상승(血壓上昇)이 나타났다. 3) 양동물(兩動物)에서 두개내압(頭盞內壓)이 혈압(血壓)보다 높아지면 현저(顯著)한 혈압하강(血壓下降)과 현저(顯著)한 일시적(一時的)인 심박감소(心搏減少)가 나타났다. 4) Reserpine 처리동물(處理動物)에서는 두개내압상승(頭蓋內驅上昇)은 혈압하강(血壓下降), 심박감소(心搏減少)를 일으켰다. 5) 6-Hydroxydopamine 처리(뇌내)동물(處理(腦內)動物)에서는 두개내압상승(頭蓋內驅上昇)에 의한 혈압상승(血壓上昇)은 비처리동물(非處理動物)에 비(比)하여 약(弱)하였다. 6) Reserpine 처리동물(處理動物)의 측뇌실내(側腦室內)에 norepinephrine을 투여(投與)한 후(後)에는 두개내압상승(頭蓋內驅上昇)은 현저(顯著)한 혈압상승(血壓上昇)을 일으켰다. 7) 두개내압상승(頭蓋內驅上昇)에 의한 혈압상승(血壓上昇)은 두개내압상승(頭蓋內驅上昇)으로써 뇌내(腦內) noradrenergic neuron이 자극(刺戟)되여 norepinephrine 유리(遊離)가 증가(增加)한 결과(結果) 일어나는 것으로 추리(推理)하였다.