• Journal of Chest Surgery
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• 제31권5호
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• pp.441-450
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• 1998

본 연구는 동맥혈압의 조절에 결정적 역할을 하는 상부연수 복외측부에 존재하는 심맥관계 활동과 관련 있는 신경세포들에 대해 iontophoresis 법으로 투여한 신경흥분전달물질의 작용기전을 규명하고자 하였다. 이를 위해서 $\alpha$-chloralose로 마취한 고양이를 실험동물로 하여 연수의 복외측부에 multibarrel 전극을 삽입하여 심맥관계 활동과 관련 있는 신경세포의 활동을 세포외기록법으로 확인한 후 세포에 iontophoresis법으로 투여한 glutamate, GABA(\ulcorner-aminobutyric acid) 및 bicuculline의 효과를 관찰하여 다음과 같은 결과를 얻었다. 1) 자발적으로 활동전압을 보이지 않는 세포에서 glutamate를 10초 주기로 5초간 iontophoresis할 때 주기적인 세포활동을 기록할 수 있었고 이 활동은 동시에 가한 GABA에 의하여 억제되었다. 2) 자발적으로 활동하고 있는 세포들에 대하여 glutamate를 투여하였을 때 활동전압의 빈도가 증가하였고 GABA에 의해서 억제되었다. 3) GABA억제제인 bicuculline을 단독으로 투여시 활동전압 빈도의 증가는 뚜렷하지 않았으나 GABA와 동시 투여시에는 GABA의 억제작용을 차단하였다. 4) GABA의 작용은 RVLM(rostral ventrolateral medulla) 세포의 주기적 활동과 basal discharge 모두를 감소시켰으나 주기적 양상이 없어진 세포는 드물었다. 5) 말초에 가한 유해자극에 의하여 유발된 신경세포 활동이 GABA에 의하여 억제되었다. 이상의 결과로부터 $\alpha$-chloralose로 마취한 고양이에서 GABA는 RVLM에 존재하는 심맥관계 신경세포들에 대하여 억제적으로 작용하나 bicuculline의 투여후에도 이들 세포들의 주기적 활동이 유지되는 점으로 보아 RVLM세포의 자발적 흥분에 대하여 감압반사의 흥분이 기여하는 바가 크지는 않을 것으로 사료된다.

• Archives of Pharmacal Research
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• 제17권4호
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• pp.263-268
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• 1994

This study was conducted to characterize the in vivo pharmacology of KR-30988, KR-30992 and losartan, new AT antagonists, given as i.v. cumulative doses, in two antimal models of high renin, conscious renal artery-ligated hypertensinve rats (RHRs) and nomotensive rats anesthetized with urethane (90 mg/kg, i.p.) and .alpha.-chloralose (90 mg/kg, i.p.), with a special emphasis on the phamacological characterization of the latter model. In conscious RHRs, KR-30988, KR-30992, losartan and captopril caused a dose-dependent decrease in blood pressure, their relative potencise ($ED_{20}$) being 0.057, 0.028, 0164 and 0.018 mg/kg, i.v., repectively. In anesthetized rats, 2 hours after anesthesia, plasma renin activity was increased from 7.31 tp 34.07 ng/ml/h, the level approximately 1.5 times greater than the highest level in RHRs. In anesthtized rats, the $ED_{20}$s for all four compounds were 0.004 mg/kg i.v., respectively. By comparison, $ED_{20}$sfrom anesthetized rats were 4 to 5 times smaller than those from conscious RHRs, with a good correlation (.gamma. = 0.999) noted between thetized rats to the hypotensive activity of the compounds and the same order of potencies intwo models. These results suggest that, in addition to PHRs, the normotensive rats anesthetized as above can serve as a suitable model for the rapid phamacological evaluation of $AT_1$ receptor antagonists.

• Tuberculosis and Respiratory Diseases
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• 제48권3호
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• pp.347-356
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• 2000

연구배경 : 수면 무호흡 증후군의 90% 이상을 차지하는 폐쇄성 수면 무호흡 증후군 환자들은 심혈관계 기능부전이 흔히 동반되며 정상인에 비하여 장기사망률이 증가하는 것으로 알려져 있다. 저자들은 동물실험을 통하여 폐쇄성 무호흡이 심혈관계 기능변화에 미치는 영향을 관찰하고자 하였으며, 또한 수면 무호흡과 관련된 앞으로의 연구에서 적절한 실험동물 모델 설정을 위한 기초자료를 얻고자 하였다. 방 법 : $\alpha$-chloralose로 마취한 16마리의 개를 대상으로 폐쇄성 무호흡을 유발하였고, 무호흡-호흡 주기를 5회 내지 7회 반복하였다. 실내 공기만으로 호흡을 유지시킨 8마리를 산소 비투여군으로 하였고 산소를 투여하면서 호흡을 유지시킨 8마리를 산소 투여군으로 하였다. 무호흡 유발 전 기저상태(기저치), 무호흡 시작 후 25초(무호흡시기), 호흡재개 후 10초(호흡재개 초기)와 25초(호흡재개 후기)에 각각 동맥혈 산소분압과 이산화탄소분압, 심박동수, 심박출량, 대퇴동맥압 및 폐동맥압을 측정하였다. 결 과 : 심박동수는 산소 비투여군에서는 기저치에 비하여 무호흡시기에 유의하게 감소하였고(P<0.01), 시기에 비하여 호흡재개 초기 및 후기에 유의하게 증가하였으며(P<0.01), 산소 투여군에서는 무호흡-호흡 주기에 따른 심박동수 변화가 없었다. 산소투여 여부에 따른 두 군 사이에는 유의한 차이가 있었다. 심박출량은 기저치에 비하여 무호흡시기에 감소하는 경향을 보였으나 통계적 유의성이 없었고, 무호흡시기에 비하여 호흡재개 후기에 유의하게 감소하였으며(P<0.01), 산소투여 여부에 따른 두 군 사이에는 유의한 차이가 없었다. 평균 대퇴동맥압은 기저치에 비하여 무호흡시기에 유의한 감소를 보였고(P<0.05), 산소투여 여부에 따른 두 군 사이에는 유의한 차이가 없었다. 결 론 : 실험동물에서 유발된 폐쇄성 무호흡은 심박동수, 심박출량 및 평균 대퇴동맥압 변화를 초래하였으며, 심박동수 변화는 저산소증과 관련성이 있었다. 본 실험을 통하여 간접적으로 혈역학적 변화에 대한 부분적인 이해가 가능하였으나, 수면 무호흡 증후군 환자에서 동반될 수 있는 심혈관계 기능부전의 병태생리학적 기전을 규명하기 위해서는 자연 수면상태에서 실험할 수 있는 새로운 동물모델의 설정과 더불어 심혈관계 기능변화 및 변화요인에 대한 다양한 연구가 필요하다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.596-596
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• 2003

The purpose of this study were to evaluate the effect of epinephrine-containing local anesthetics on pulpal blood flow (PBF) and to compare the change of pulpal blood flow after cavity preparation between in non-anesthetized teeth and in anesthetized ones in cats. Nine cats were initially anesthetized with intra-muscular injection of keramine(75mg/kg) and acepromazine(2.5mg/kg). Periapical radiographs of canine teeth were taken, followed by intra-venous injection of alpha-chloralose(40mg/kg) and urethane (500mg/kg) through the femoral vein for the general anesthesia.(중략)

• The Korean Journal of Physiology
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• 제25권2호
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• pp.201-209
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• 1991

The rostral ventrolateral medulla (RVLM) has been established recently as a sympathoexcitatory area. The present study was conducted to investigate whether the somatosympathetic pressor and/or depressor responses are mediated through RVLM in cats anesthetized with ${\alpha}-chloralose$. An occipital craniectomy was performed and ventrolateral medulla were stimulated either electrically or chemically to evoke changes in arterial blood pressure. And then the effect of lesions in the ventrolateral medulla on the changes in blood pressure elicited by the peripheral nerve stimulation was observed. Followings are the results obtained: 1) Pressor areas were found in the ventrolateral medulla, lateral reticular nucleus and rostral dorsal area. 2) Depressor areas were found mainly in the ventrolateral medulla rostral to the pressor areas. 3) Some areas showed biphasic responses: a depressor response to lower frequency and a pressor response to higher frequency stimulation. 4) After electrical lesion in pressor area in RVLM, the somatosympathetic pressor response was abolished or depressed markedly. The somatosympathetic depressor response, however, remained after the lesion. 5) Electrical lesion in the depressor area abolished somatosympathetic depressor response. From the above results it is concluded that somatosympathetic pressor response is mediated through RVLM, while somatosympathetic depressor response is not mediated through RVLM.

• The Korean Journal of Physiology
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• 제29권2호
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• pp.309-321
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• 1995

In the present study, the relationship between the somatosympathetic reflexes and arterial blood pressure responses to electrical stimulation of the peripheral nerve was investigated in cats anesthetized with ${\alpha}-chloralose$. Single sympathetic postganglionic fiber activities were recorded from the hindlimb muscle and skin nerves and also from the cervical and abdominal sympathetic chains. Effects of the morphine on responses of the sympathetic nerve and arterial blood pressure to activation of the peripheral $A{\delta}-$ and C-afferent nerves were analyzed. The following results were obtained. 1) Arterial blood pressure was depressed by peripheral AS-afferent stimulation (A-response) and was elevated during C-afferent activation (C-response). 2) Intravenously administered morphine enhanced the C-response while the A-response decreased insignificantly, Only the C-response was decreased by intrathecal morphine. 3) All the ten recorded cutaneous sympathetic fibers showed periodic discharge pattern similar to respiratory rhythm and five of them also showed cardiac-related rhythm. However, most of the muscular sympathetic fibers had cardiac-related rhythm and only four fibers showed respiratory rhythm. 4) Morphine decreased the sympathetic C-reflex elicited by the peripheral C-afferent activation and the abdominal sympathetic A-reflex was also decreased by morphine. From the above results, it was concluded that supraspinal mechanisms were involved in the enhanced arterial pressor response to peripheral C-afferent activation by intravenous morphine.

• The Korean Journal of Physiology
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• 제25권2호
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• pp.211-221
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• 1991

Although the existence of nerve cells which determine the activity of sympathetic nervous system in ventrolateral medulla is advocated recently, there are wide varieties on the location and function of them according to authors. Present study aimed to identify and characterize the medullospinal tract cells in rostral and caudal medulla of cats .which branch to the lateral horn of the upper thoracic spinal cord. Cats were anesthetized with ${\alpha}-chloralose$. The upper thoracic spinal cord and floor of the IVth ventricle were exposed. Medullospinal tract cells in rostral and caudal medulla were identified by anti-dromic stimulation of the intermediolateral nucleus in the upper thoracic cord and then the location and physiological characteristics of these cells were studied. A total of seventy cells in medulla had constant latency and responded to high frequency stimulation to thoracic cord. Among them fifty-six cells were identified as medullospinal tract cells either by collision with spontaneous activities or activities evoked by sciatic nerve stimulation(27/56), or by determining the refractory period (29/56). Thirty-one of these cells branched to the contralateral thoracic spinal cord, twenty-one cells to the ipsilateral side and remaining four cells branched to both sides. The conduction velocity of cells branching to the contralateral side was $29{\pm}2.9\;m/sec$ and that of cells to the ipsilateral side was $39.1{\pm}6.0\;m/sec$. When medulla was devided into two by a horizontal plane at 3 mm rostral to the obex, fifty-one among seventy cells were in the rostral medulla and nineteen were in the caudal medulla. The conduction velocities of these two groups were $21.6{\pm}1.0\;and\;33.3{\pm}3.9\;m/sec$, respectively. In this study, we confirmed the existence of two groups of medullospinal tract cells in rostral and caudal ventrolateral medulla, which branch to the lateral horn of thoracic cord and these cells have relatively few spontaneous activities and rapid conduction velocity, so we concluded that these cells are different from the previously known sympatho-related cells in ventrolateral medulla.

• The Korean Journal of Physiology
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• 제24권1호
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• pp.171-180
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• 1990

In 19 cats anesthetized with ${\alpha}-chloralose$ effects of taurine and ${\beta}-alanine$ on the responses of wide dynamic range (WDR) cells to mechanical, chemical and thermal stimuli were investigated in the lumbar spinal cord of the cat. Also studied was an interaction of strychnine with taurine in affecting the activities of WDR cells. Following intravenous administration of taurine, the responses of WDR cells to all types of mechanical stimuli were markedly enhanced, demonstrating that the response to pressure was most sensitive to taurine action. When the receptive field was exposed to thermal stimuli ($50^{\circ}C$) for 20 sec. taurine increased activity of WDR cell to 169.5% of the control value. The $K^{+}$-induced activation of WDR cells was invariably suppressed after taurine administration. Intravenously administered strychnine remarkably reduced the enhanced response of WDR cell to natural stimuli resulting from intravenous administration of taurine. Also ${\beta}-alanine$ markedly activated the response of spinal dorsal horn cell to natural mechanical stimuli. These findings suggest that neutral amino acid and its derivative such as ${\beta}-alanine$ and taurine can enhance the response of WDR cells to different stimuli in cats.

• The Korean Journal of Physiology
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• 제21권1호
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• pp.59-66
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• 1987

This study was aimed to investigate whether the conduction velocity of nerve impulses through the ventral afferent fibers is constant along their entire courses in dorsal as well as in ventral roots. Cats were anesthetized with ${\alpha}-chloralose$ (60 mg/kg, i.p.) and artificially ventilated. Laminectomies were done on L4-S1 spinal vertebrae to expose the lumbosacral spiral cord. Both ventral and dorsal roots of L7 or S1 spinal segments were isolated and cut near the spinal cord. Ventral roots were placed on 6-lead stimulating electrodes and stimulated with supra C-threshold intensity. Divided dorsal root fascicles were placed on bipolar recording electrodes and single fiber units activated by the stimulation of the ventral roots were identified. Followings are the results obtained: 1) A total of 27 VRA units were identified. 10 units of them conducted impulses slower than 2 m/sec. Conduction velocities of the remaining units were in the range of 3.11-20.91 m/sec. 2) In 12 Units conduction velocities Of the VRA units through dorsal$(CV_{DR})$ and venral root$(CV_{DR})$ were determined respectively. There was a tendency to conduct impulses faster through dorsal roots$(CV_{DR}=8.19{\pm}3.26\;m/sec)$ than ventral roots$(CV_{DR}=3.46{\pm}1.02\;m/sec)$. From the above results we confirmed that there exist nerve fibers in continuity between the spinal ventral and dorsal roots but we could not ascertain whether there is a change in conduction velocity through the entire course of ventral afferent unit.

• Restorative Dentistry and Endodontics
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• 제29권3호
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• pp.239-248
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• 2004

The purpose of this study was to investigate the influence of NK1 receptor antagonists on the pulpal blood flow (PBF) when applied iontophoretically through the dentinal cavity of the teeth in order to understand whether iontophoretically applied NK1 receptor antagonists can control the pulpal inflammation. Eleven cats were anesthetized with alpha-chloralose and urethane, and substance P (SP) was administered to the dental pulp through the catheterized lingual artery in doses that caused PBF change without the influence of systemic blood pressure. NK1 receptor antagonists were applied iontophoretically to the prepared dentinal cavity of ipsilateral canine teeth of the drug administration, and PBF was monitored. Data were analyzed statistically with paired t-test. PBF increase after iontophoretic application of the NK1 receptor antagonists followed by the intra-arterial administration of SP was significantly less than PBF increase after iontophoretic application of the 0.9% saline followed by the intra-arterial administration of SP as a control (p < 0.05). Iontophoretic application of the NK1 receptor antagonists (0.2~3.4 mM) following the intra-arterial administration of SP resulted in less increase of PBF than the iontophoretic application of the 0.9% saline following the intra-arterial administration of SP as a control (p < 0.05). Therefore. the results of the present study provide evidences that the iontophoretic application is an effective method to deliver drugs to the dental pulp. and that iontophoretically applied NK1 receptor antagonists block SP-induced vasodilation effectively. The above results show the possibility that the iontophoretical application of NK1 receptor antagonists can control the neurogenic inflammation in the dental pulp.