• The Korean Journal of Physiology
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• 제28권2호
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• pp.197-202
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• 1994

The present study was aimed to determine if endogenous L-arginine-nitric oxide (NO) pathway has central, rather than peripheral, mechanisms in blood pressure regulation. Arterial blood pressure and heart rate responses to acute inhibition of the t-arginine-NO pathway were examined in rats anesthetized with thiopental (50 mg/kg, IP). An intracerebroventricular (ICV) cannula was placed in the left lateral ventricle. The right femoral artery was cannulated to measure arterial blood pressure and the vein to serve as an infusion route. $N^G-nitro-L-arginine$ methyl ester (L-NAME) was infused either intracerebroventricularly or intravenously. ICV infusion $(1.25\;{\mu}L/min)$ of L-NAME $(20\;or\;100\;{\mu}g/kg)$ per minute for 60 min) increased the mean arterial pressure and heart rate. Plasma renin concentrations(PRC) were significantly lower in L-NAME-infused group than in the control. L-Arginine $(60\;{\mu}g/min,\;ICV)$ prevented the pressor response to ICV L-NAME. The pressor response was not affected by simultaneous intravenous infusion of saralasin, but was abolished by hexamethonium treatment. Intravenous infusion $(40\;{\mu}L/min,\;10{\sim}100\;{\mu}g/kg\;per\;minute\;for\;60\;min)$ also increased blood pressure, while it decreased heart rate. These results indicate that endogenous L-arginine-NO pathway has separate central and peripheral mechanisms in regulating the cardiovascular function. The central effect may not be mediated via activation of renin-angiotensin system, but via, at least in part, activation of the sympathetic outflow.

• Asian-Australasian Journal of Animal Sciences
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• 제13권11호
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• pp.1529-1535
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• 2000

The aim of the present study was to determine whether brain corticotropin-releasing factor (CRF) and a new peptide, urocortin (UCN) have a direct action in brain mechanisms controlling feed, water and salt intake in sheep. We gave a continuous intracerebroventricular (ICV) infusion of the peptide at a small dose of $5{\mu}g/0.2ml/hr$ for 98.5 hrs from day 1 to day 5 in sheep not exposed to stress. Feed and water intake during ICV infusion of CRF or UCN decreased significantly compared to those during artificial cerebrospinal fluid (CSF) infusion. NaCl intake during infusion of CRF or UCN was the same as that during CSF infusion. Mean carotid arterial blood pressure (MAP) and heart rate during ICV infusion of CRF or UCN were not significantly different from that during CSF infusion. On the other hand, the plasma glucose concentration during ICV infusion of CRF or UCN tended to be higher than that during CSF infusion. These observations indicate that decreased feed intake induced by CRF and UCN infusion is not mediated by the activation of both the pituitary-adrenal axis and the sympathetic nervous system. The results suggested that brain CRF and UCN act directly in brain mechanisms controlling ingestive behavior to decrease feed and water intake, but do not alter salt intake in sheep.

• 대한의용생체공학회:의공학회지
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• 제43권4호
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• pp.193-198
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• 2022

Contrast enhanced magnetic resonance imaging using gadolinium-based contrast agent (GBCA) is a very useful in vivo technique to visualize the inner ear pathology including endolymphatic hydrops. Although systemic intravenous (IV) administration can visualize the perilymph space, the visualization was possible by indirect passage of contrast agent through blood-perilymph barrier. All animal experimental procedures were performed under anesthesia with 5% isoflurane. Lipopolysaccharide (LPS) was instilled into the left tympanic cavity through the tympanic membrane using a sterile 27gauge needle to induce hydrops model. Tucker-Davis Technologies system was used to measure Auditory Brainstem Responses (ABRs). For intracerebroven-tricular (ICV) administration, 25 µmol of GADOVIST (Bayer, Berlin, Germany) was used and diluted GADOVIST injection was 10 µl. MR imaging was acquired with a 9.4 Tesla MRI scanner. Transmit-receive volume coil with 40 mm inner diameter and 75 mm out diameter was used. ICV administration well demonstrated the strong enhancement along the cerebrospinal fluid (CSF) microcirculation pathway including CSF fluid in the subarachnoid space and CSF space of the inner ear structures. On the other hand, IV administration showed no contrast enhancement along the CSF microcirculation pathway and showed weak enhancement in the inner ear structures. In case of rat hydrops model, ICV administration showed that the reduced contrast enhancement in the perilymph space of the hydrops induced inner ear compared to the contrast enhancement in the perilymph space of the normal inner ear. New systemic ICV administration method provide contrast enhancement of GBCA in the inner ear through CSF microcirculation pathway.

• Korean Journal of Radiology
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• 제22권3호
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• pp.395-404
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• 2021

Objective: To compare the utility of computed tomography perfusion (CTP) and three different 4-point scoring systems in computed tomography angiography (CTA) in confirming brain death (BD) in patients with and without skull defects. Materials and Methods: Ninety-two patients clinically diagnosed as BD using CTA and/or CTP for confirmation were retrospectively reviewed. For the final analysis, 86 patients were included in this study. Images were re-evaluated by three radiologists according to the 4-point scoring systems that consider the vessel opacification on 1) the venous phase for both M4 segments of the middle cerebral arteries (MCAs-M4) and internal cerebral veins (ICVs) (A60-V60), 2) the arterial phase for the MCA-M4 and venous phase for the ICVs (A20-V60), 3) the venous phase for the ICVs and superior petrosal veins (ICV-SPV). The CTP images were independently reviewed. The presence of an open skull defect and stasis filling was noted. Results: Sensitivities of the ICV-SPV, A20-V60, A60-V60 scoring systems, and CTP in the diagnosis of BD were 89.5%, 82.6%, 67.4%, and 93.3%, respectively. The sensitivity of A20-V60 scoring was higher than that of A60-V60 in BD patients (p < 0.001). CTP was found to be the most sensitive method (86.5%) in patients with open skull defect (p = 0.019). Interobserver agreement was excellent in the diagnosis of BD, in assessing A20-V60, A60-V60, ICV-SPV, CTP, and good in stasis filling (κ: 0.84, 0.83, 0.83, 0.83, and 0.67, respectively). Conclusion: The sensitivity of CTA confirming brain death differs between various proposed 4-point scoring systems. Although the ICV-SPV is the most sensitive, evaluation of the SPV is challenging. Adding CTP to the routine BD CTA protocol, especially in cases with open skull defect, could increase sensitivity as a useful adjunct.

• Investigative Magnetic Resonance Imaging
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• 제19권1호
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• pp.10-18
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• 2015

Background and Purpose: The association between the low emotional regulation and the brain structural change of major depressive disorder (MDD) has been proposed, but the voxel-based morphometry (VBM) studies on female MDD are rare. The purpose of the present study was to show the regional volume changes of gray matter (GM) in female patients with MDD by optimized VBM. Methods: To control subjects homogeneity, twenty female MDD patients and age, sex matched 21 normal controls were included for the VBM analysis. To identify the change of regional gray matter volume (GMV), the optimized VBM was performed with T1 MRIs. The amounts of gray/white matter and intracranial cavity volumes (ICV) were measured. The analysis of covariance (ANCOVA) and partial correlation analyses covariate with age and ICV were applied for VBM. Results: The age and ICV distributions were similar between the two groups. In the ANCOVA, the total GMV of MDD was smaller than that of normal controls. In the VBM, regional GMV was relatively decreased in the limbic system (amygdalae, ambient gyri, hippocampi heads, subiculum, posterior parahippocampal gyri, pulvinar nuclei, dorsal posterior cingulate gyri, and left pregenual cingulate gyrus). The lingual gyri, short insular gyri, right fusiform gyrus, and right inferior frontal gyrus were also showed decreased regional GMV. Conclusion: The results of this study indicate that the female MDD is mainly associated with the structural deficits of the limbic system and limbic system related cortices, which were known to the center of emotions.

• The Korean Journal of Physiology
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• 제28권2호
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• pp.191-196
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• 1994

Captopril, an inhibitor of angiotensin converting enzyme, is also known to inhibit the degradation of bradykinin. We examined the effects of intracerebroventricular (ICV) captopril on the central pressor response to bradykinin in normotensive, 2-kidney, 1 clip Goldblatt (GHR) and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Captopril (1 mg) and bradykinin (5 nmol) were administered into the right lateral cerebral ventricle, and blood pressure and heart rate were continuously monitored throughout the experiment. ICV captopril alone did not affect the blood pressure within 10 minutes but it significantly augmented the central pressor response to bradykinin in GHR. On the contrary, captopril was without effect on the pressor response to bradykinin in normotensive and DOCA-salt rats. These findings indicate that endogenous kinins are not critical in regulating arterial pressure in normotensive and DOCA hypertensive rats. However, in GHR, an enhanced activity of the brain kallikrein-kinin system in maintaining the high blood pressure is suggested.

• Animal Bioscience
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• 제35권12호
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• pp.1904-1910
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• 2022

Objective: This study aimed to investigate the effects of corticotropin-releasing factor (CRF) on the feed intake of broiler chickens and explore its influencing mechanism. Methods: The study included two trials. In trial 1, 32 male broiler chickens (Arbor Acres, Gallus gallus domesticus) were given ventricle buried tubes, and they were allowed to recover for 3 days. At 8:00 AM, intracerebroventricular (ICV) injection with CRF or normal saline was performed in 10-day-old broiler chickens, which were divided into the 5, 10, and 20 ㎍ and control (normal saline) groups according to the dose of CRF injection. In trial 2, chickens were divided into the 10 ㎍ and control group (physiological saline) to repeat trial 1. Results: Results of trial 1 showed that the cumulative amount of feed intake in the 10 or 20 ㎍ groups was considerably lower than that of the control group after ICV injection with CRF. The lowest amount of feed intake was obtained with the addition of 10 ㎍ of CRF. In trial 2, the expression of ghrelin in the hypothalamus injected with 10 ㎍ of CRF increased significantly, but the expression of ghrelin in various sections of the small intestine considerably decreased. The expression of CRF receptor subtypes 1 (CRFR1) in the hypothalamus and some parts of the small intestine remarkably increased, and the expression of CRF receptor subtypes 2 (CRFR2) increased only in the duodenum, whereas the expression of growth hormone secretagogue receptor (GHSR-1α) in the jejunum and ileum increased considerably after ICV injection of 10 ㎍ of CRF. Conclusion: The CRF at 10 ㎍ increased ghrelin expression in the hypothalamus and CRFR1 expression in the small intestine, and this phenomenon was related to the suppressed feed intake of broiler chickens.

• 대한약리학회지
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• 제27권1호
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• pp.21-31
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• 1991

미주신경절단 가토에서 니코틴성약물인 nicotine과 DMPP뿐아니라 무스카린성 약물인 muscarine과 bethanechol은 측뇌실내 투여로 모두 혈압상승작용을 나타냈다. Nicotine과 DMPP에 대한 승압반응은 측뇌실내 mecamylamine처리로 현저히 감약되었으나 측뇌실내 pirenzepine처리에 의해서는 영향받지 않았고, muscarine과 bethanechol에 대한 승압반응은 pirenzepin에 의해서는 억제되나 mecamylamine에 의해서는 영향받지 않았다. 이는 뇌내의 니코틴성 수용체 및 무스카린성 수용체가 모두 혈압상승에 관여함을 가리키고 있다. Nicotine과 muscarine에 대한 승압반응은 regitine, reserpine, enalapril, saralasin, SK&F-100273, regitine과 enalapril, regitine과 saralasin의 정맥내 처리에 의해서는 억제되지 않았으며 nicotine에 대한 승압반응은 regitine과 SK&F-100273 두약물의 병용처리에 의해서 억제되었고 muscarine에 의한 승압반응은 regitine, enalapril과 SK&F-100273의 세가지 약물의 병용처리에 의해서만 억제되었다. Nicotine이나 muscarine에 의한 혈압상승상태에서 정맥내 regitine의 투여는 혈압하강을 일으켰으나 enalapril이나 SK&F-100273은 혈압하강을 일으키지 못하였다. Enalapril은 regitine처리나 regitine과 SK&F-100273병용처리 가토에서 nicotine에 의해 상승된 혈압을 하강시키지 못하였으나 SK&F-100273은 regitine처리 가토에서 nicotine에 의한 상승된 혈압을 하강시켰다. Enalapril은 이러한 SK&F-100273의 할압하강작용을 강화시키지 못하였다. Enalapril은 regitine 처리 가토에서 muscarine에 의하여 상승된 혈압은 하강시키지 못하였으나, regitine과 SK&F-100273병용처리 가토에서 muscarine에 의해 상승된 혈압은 하강시켰다. SK&F-100273은 regitine처리 가토에서 muscarine에 의해 상승된 혈압을 하강시키지 못했으나 regitine과 enalapril병용처리 가토의 상승된 혈압은 하강시켰다. 이상의 성적은 뇌실내 nicotine에 의한 혈압상승에는 말초에서 교감신경계와 vasopressin이 관여하며 muscarine에 의한 혈압상승에는 교감신경계, vasopressin 및 angiotensin계가 관여함을 시사하고 있다. Regitine의 정상 가토 혈압하강작용은 enalapril이나 SK&F-100273의 단독처리에 의해서는 영향받지 않았으나 이 두약물을 병용처리시에는 유의하게 강화되었고, 이는 가토 동맥압의 유지에 교감신경, renin-angiotensin 및 vasopressin계가 관여함을 시사하고 있다.

• 대한약리학회지
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• 제29권1호
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• pp.23-32
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• 1993

GABA계가 뇌내의 교감신경계기능에 영향을 주어서 혈압조절에 관여함이 알려져 있다. 본 연구에서는 마취가토에서 GABA계가 두개내압증가에 의한 혈압상승에 관여하는가를 조사하였다. 두개내압증가에 의한 승압은 측뇌실내 muscimol (GABA 작용약)이나 clonidine $({\alpha}_2$-작용약) 전처리후에는 볼 수 없었다. 측뇌실내 yohimbine $({\alpha}_2$-길항약)으로 일으킨 고혈압은 두개내압증가를 하여도 더 이상 상승하지 않았으나, 측뇌실내 bicuculline (GABA 길항약)으로 일으킨 고혈압은 두개내압증가로 더욱 상승하였다. Bicuculline은 muscimol이나 clonidine 저혈압에서는 승압을 일으켰으나 yohimbine이나 두개내압증가에 의한 고혈압에서는 무효였다. Yohimbine은 clonidine 저혈압은 상승시켰으나 muscimol 저혈압에 있어서는 무효였다. Yohimbine은 두개내압증가에 따른 승압상태는 더 올리지 못하였으나 bicuculline 승압상태는 더욱 상승시켰다. Muscimol은 bicuculline과의 길항성이외에 yohimbine 승압을 억제함을 알았으며 yohimbine 승압에 GABA계가 관여함을 추측할 수 있었다. 이러한 실험결과로 두개내압증가에 따른 승압상승은 (1) ${\alpha}_{2}$-수용체, (2) bicuculline-감수성 GABA 수용체, (3) yohimbine-감수성인 clonidine이 작용하는 GABA계 부위의 세가지 방법으로 억제성인 교감신경기능을 불활성화하여 일어나는 것으로 추론하였다.

• 한국추진공학회지
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• 제8권4호
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• pp.76-83
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• 2004

CRW Tyre UAV 추진시스템은 수직으로 이착륙이 가능하고 고정익으로 고속 전진 비행이 가능한 개념으로 설계되었다. 이를 위해 추진시스템은 이착륙 시에는 로터를 구동시켜 수직으로 비행하고 고속 비행 시에는 로터를 정지시켜 날개로 사용하고 가스발생기에서 생성된 가스를 주 노즐로 분사하여 본래의 제트엔진으로 사용한다. ICV방법과 SIMULINK를 이용하여 천이 성능 해석을 수행하였다. 연료유량은 터빈 입구온도의 스텝과 과온 현상을 피하기 위해 램프 증가를 하였고 이에 따른 추력의 변화와 터빈 입구온도의 변화를 살펴보았다.