• The Korean Journal of Pharmacology
• /
• v.14 no.1_2
• /
• pp.13-23
• /
• 1978

1) It was attempted to clarify the sites of action of central (either intraventricular or intracisternal) norepinephrine(NE) and clonidine to cause cardiac slowing and hypotension in urethane-anesthetized rabbits. 2) NE produced cardiac slowing but indistinct effect on blood pressure. Clonidine produced cardiac slowing and hypotension. 3) Intraventricular and intracisternal administration of NE, clonidine, phenylephrine and isoproterenol did not make difference in their effects, except that the onset of cardiac slowing by intracisternal NE was more rapid than intraventricular NE. 4) Upon repeated administration of NE at the intervals of about two hours, blood pressure responses changed to the pressor ones, the cardiac slowing unchanged. By this procedure the cardiac slowing as well as the hypotension by clonidine were gradually diminished. 5) Clonidine, when given during the NE effects were persisting, did not produce the lowering of blood pressure and further decrease of heart rate. NE, when given during the clonidine effects were persisting, produced marked elevation of blood pressure but did not produce further decrease of heart rate. 6) After intraventricular administration of regitine or desmethylimipramine, the cardiac slowing effect of NE and the clonidine effects were not observed, whereas NE produced marked elevation of blood pressure. 7) Reserpinized rabbits showed pressor and cardiac accelerating responses to NE; slight pressor, and little cardiac responses to clonidine. 8) It seems that the cardiac slowing by both clonidine and NE as well as the hypotetsion by clonidine are mediated by the presynaptic ${\alpha}$-adrenoceptor in the brain but the pressor responses to NE and clonidine are mediated by other site(s) than the presynaptic ones.

• Journal of Chest Surgery
• /
• v.31 no.9
• /
• pp.884-892
• /
• 1998

Background: The gastroepiploic artery is not only an alternative graft but also may be considered an important primary graft for coronary revascularization. However, the long-term patency of the gastroepiploic arterial graft is yet to be determined and the incidence of perioperative spasm and long-term patency of a coronary graft may be affected by the properties of the graft response to certain vasoactive substances. The reactivity of the gastroepiploic artery to vasoactive substances has not been studied extensively and the results of the studies are contradictory. Material and Method: This study was designed to test the reactivity of human gastroepiploic artery to four constrictors and four relaxants. The middle sections of the human gastroepiploic arteries were collected from the patients undergoing gastrectomy and the arterial rings with intact endothelium were suspended in organ baths for isometric tension recording. Result: Epinephrine, norepinephrine, and potassium chloride induced the maximum constriction to higher forces (7.0$\pm$1.1g, 6.6$\pm$0.9g, and 6.5$\pm$1.1g) than 5-hydroxytryptamine did (3.8$\pm$1.7g, p<0.05). Nitroprusside and histamine induced almost full relaxation in the gastroepiploic arteries preconstricted with norepinephrine. There was no significant difference between two relaxants regarding maximum relaxation force. Acetylcholine induced the maximum relaxation to weaker force when compared with nitroprusside and histamine (p<0.05), and isoproterenol was the weakest of the relaxants (p<0.05 compared with acetylcholine). Conclusion: The gastroepiploic artery has a strong capacity of endothelium-dependent relaxation which could have an important influence on long-term patency. The gastroepiploic artery exhibits a potent contractility to catecholamines and the enhanced contractility may facilitate vasospasm in the presence of high circulating levels of catecholamines. Nitroprusside, a potent relaxant in gastroepiploic artery, might be beneficial for the treatment of gastroepiploic arterial graft spasm. The gastroepiploic arterial graft with intact endothelium may respond weakly to beta-adrenoceptor agonist and 5-hydroxytryptamine.

• Neonatal Medicine
• /
• v.18 no.2
• /
• pp.395-398
• /
• 2011

Sick sinus syndrome (SSS) is a disorder characterized by sinus node dysfunction. Although the condition is most common in the elderly, it can occur in children including neonates and its recognition and treatment are important. The diagnosis of SSS is based on the presence of sinus bradycardia, sinus arrest or exit block, combinations of sinoatrial and atrioventricular nodal conduction disturbances, and atrial tachyarrhythmias documented in the Holter recordings. In most children with SSS, previous history of congenital heart malformation or cardiac surgery is noted. SSS is also seen in the children including neonates without heart disease or other contributing factors, however SSS is most often idiopathic. The treatment of SSS depends on the basic rhythm problem, but generally involves the placement of a cardiac pacemaker. We report a case of SSS in extremely low birth weight infant without congenital heart disease and suggest that the treatment system is necessary for preterm infants with SSS.

• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.870-870
• /
• 2005

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1992.05a
• /
• pp.47-47
• /
• 1992

$\beta$수용체에 대한 차단약으로 propranolol이 1964년에 도입된 후, 현재까지 수십여종의 $\beta$-차단약이 개발되었다. 그중 특이 $\beta$1 수용체에 대해 선택적인 억제효과를 지닌 atenolol, metoprolol, betaxolol, celiprolol 및 최근에 bisoprolol 등이 개발되어 임상적으로 부정맥, 협심증, 고혈압의 치료에 사용되고 있다. 그 작용기전으로는 심박출량의 감소, renin 유리억제, 중추억제효과 등이 제시되고 있으나, 이들의 약효검색은 주로 $\beta$1수용체가 많이 존재하는 심장에 대한 억제효과를 중심으로 실시한다. 즉, SHR 및 개를 사용한 생체실험과 심장, 심방 ($\beta$1) 및 기완지, 혈관($\beta$2)을 이용한 적출장기실험을 통하여 isoproterenol에 대한 억제효과를 용량반응 곡선으로 그리고, Van rossum 법에 의해 pA$_2$ 치를 구하여 $\beta$-차단제의 효력을 평가한다. 특히, pA$_2$ 치가 클수록 $\beta$-차단제의 효력이 큰 약물이다. 또한 수용체 결합실험으로 소의 심실 세포막을 분리하여 $^3$H-DHA 와의 결합실험을 통해 해리항수(Kd) 를 측정하고, 이어서 $^3$H-DHA의 일정농도와 함께 미지의 $\beta$-차단제를 여러 농도로 변화시켜 가하여 치환곡선을 작성한다. 여기에서 얻은 치환약의 $IC_{50}$/ 치로부터 치환약의 해리항수(Ki)를 산출한다. 이때 약물과 수용체의 친화력은 해리항수의 역수이므로 해리항수가 적을수록 $\beta$ 수용체에 대한 친화력이 큰 약물이다. 시사되었으며, 이 조직에서 또한 5-$HT_2$와 5-$HT_3$ 수용체의 존재를 확인하고 각각의 기능을 분명히 했다.가 수월하게 하였고 메모리를 동적으로 관리할 수 있게 하였다. 또한 기존의 smpl에 디버깅용 함수 및 설비(facility) 제어용 함수를 추가하여 시뮬레이션 프로그램 작성을 용이하게 하였다. 예를 들면 who_server(), who_queue(), pop_Q(), push_Q(), pop_server(), push_server(), we(), wf(), printfct() 같은 함수들이다. 또한 동시에 발생되는 사건들의 순서를 조종하기 위해, 동시에 발생할 수 있는 각각의 사건에 우선순위를 두어 이 우선 순위에 의하여 사건 리스트(event list)에서 자동적으로 사건들의 순서가 결정되도록 확장하였으며, 설비 제어방식에 있어서도 FIFO, LIFO, 우선 순위 방식등을 선택할 수 있도록 확장하였다. SIMPLE는 자료구조 및 프로그램이 공개되어 있으므로 프로그래머가 원하는 기능을 쉽게 추가할 수 있는 장점도 있다. 아울러 SMPLE에서 새로이 추가된 자료구조와 함수 및 설비제어 방식등을 활용하여 실제 중형급 시스템에 대한 시뮬레이션 구현과 시스템 분석의 예를 보인다._3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorphous regions.의 증발산율은 우기의 기상자료를 이용하여 구한 결과 0.05 - 0.10 mm/hr 의 범위로서 이로 인한 강우손실량은 큰 의미가 없음을 알았다.재발이 나타난 3례의 환자를 제외한 9례 (75%)에서는 현재까지 재발소견을 보이지 않고 있다. 이러한 결과는 다른 보고자들과 유사한 결과를 보이고 있지만 아직까지 증례가 많지 않기 때문에 생존율을 얻기에는 미흡한 점이

• Archives of Plastic Surgery
• /
• v.34 no.3
• /
• pp.291-297
• /
• 2007

Purpose: Platelet-rich plasma(PRP) contains protein growth factors, which are actively secreted by platelets to promote wound healing. However, it is not clear whether the injection of PRP into the autologous fat grafts increases the survival rate and the degree of angiogenesis. Methods: New Zealand White rabbit ears were injected fat with PRP, saline, insulin or isoproterenol (n=8/each group) for observation of the survival and degree of angiogenesis of the injected fat. The volume of the harvested fat and the degree of angiogenesis from dorsum of rabbit ears were evaluated 4, 8, and 12 weeks after the autologous fat graft. The degree of angiogenesis was measured with microvascular density (MVD) counts. Results: The volume of harvested fat decreased in a time-dependent manner after autologous fat grafts, but the decrease rate in volume of harvested fat was slower in PRP-injected group compared to that of other control groups. The difference in the volume of the harvested fat between PRP-injected group and other control groups became significant from 4 weeks after the autologous fat graft, and was maintained up to 12 weeks. However, there was no significant difference between PRP-injected group and insulin-injected group 8 and 12 weeks after the autologous fat graft. On the contrary, MVD counts increased in a time-dependent manner after autologous fat grafts. The MVD counts were significantly higher in PRP-and insulin-injected groups than in other control groups from 4 weeks after the autologous fat graft, and these differences were maintained up to 12 weeks. There was no correlation between mean platelet numbers and the volume of harvested fat. Conclusion: The present study demonstrates that PRP-injection into autologous fat grafts increases the survival rate and the degree of angiogenesis. Thus, PRP injection with autologous fat grafts would be a promising tool for maintaining the volume of the grafted fat.

• The Korean Journal of Physiology and Pharmacology
• /
• v.11 no.5
• /
• pp.175-182
• /
• 2007

Members of prostaglandin(PG) E-series elicit cellular effects mainly through adenylyl cyclase-cAMP signaling. The role of $PGE_2$-induced increase in cAMP has been shown to be compartmentalized in the cardiac myocytes: $PGE_2$-induced increase of cAMP is not involved in the control of cardiomyocytic contraction. The purpose of the present study was to define the effect of $PGE_1$ on the cGMP levels and the role of $PGE_1$ in the atrial secretory function. Experiments were performed in perfused beating rabbit atria and atrial contractile responses, cGMP and cAMP efflux, and atrial natriuretic peptide(ANP) secretion were measured. $PGE_1$ increased cGMP as well as cAMP efflux concentration in a concentration-dependent manner, however, no significant changes in atrial secretory responses were observed(with $1.0{\mu}M\;PGE_1$; for cGMP, $144.76{\pm}37.5%$, n=11 versus $-16.81{\pm}4.76%$, n=6, control, p<0.01; for cAMP, $187.60{\pm}41.52%$, n=11 versus $7.38{\pm}19.44%$, n=6, control, p<0.01). $PGE_1$ decreased atrial dynamics slightly but transiently, whereas $PGE_2$ showed similar effects but with lower potency. Isoproterenol increased atrial cAMP efflux(with 2.0 nM; $145.71{\pm}41.89$, n=5 versus $7.38{\pm}19.44%$, n=6, control, p<0.05) and mechanical dynamics and decreased ANP secretion. The $PGE_1$-induced increase in cGMP efflux showed a bell-shaped concentration-response curve. $PGE_1$-induced increase of cGMP efflux was not observed in the presence of L-NAME, an inhibitor of nitric oxide(NO) synthase, or ODQ, an inhibitor of NO-sensitive guanylyl cyclase. L-NAME and ODQ showed no significant effect on the $PGE_1$-induced transient decrease of atrial dynamics. These data indicate that $PGE_1$ increases cGMP levels via NO-soluble GC signaling in the cardiac atrium and also show that $PGE_1$-induced increases in cGMP and cAMP levels are not involved in the regulation of atrial secretory and contractile functions.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.23-23
• /
• 2003

It has been suggested that the impairment of smooth muscle cell (SMC) function by alterations in the $Ca^{2+}$-activated $K^{+}$ ( $K_{Ca}$ ) channels accounts for the reduction in coronary reserve during left ventricular hypertrophy (LVH). However, this hypothesis has not been fully investigated. The main goal of this study was to assess whether the properties of $K_{Ca}$ channels in coronary SMCs were altered during LVH. New Zealand white rabbits (0.8-1.0 kg) and Sprague-Dawley rats (300-400 g) were randomly selected to receive either an injection of isoproterenol (300 $\mu\textrm{g}$/kg body weight) or an equal volume of 0.9％ saline (1 mL/kg body weight). The animals developed LVH 10 days after injection. In patch-clamp experiments, the unitary current amplitude and open probability for the $K_{Ca}$ channels were significantly reduced in LVH patches compared with control patches. The concentration-response curve of the $K_{Ca}$ channel to [C $a^{2+}$]$_{i}$ was shifted to the right. Inhibition of the $K_{Ca}$ channels with TEA was more pronounced in LVH cells than in the control cells. The whole-cell currents of $K_{Ca}$ channels were reduced during LVH. Western blot analysis indicated no differences in $K_{Ca}$ channel expression between the control and LVH coronary SM membranes. In contraction experiments, the effect of a high $K^{+}$concentration on the resting tension of the LVH coronary artery was greater than on that of the control. The effect of TEA on the resting tension of the LVH coronary artery was reduced as compared with the effect on the control. Our findings imply a novel mechanism for reduced coronary reserve during LVH.ing LVH.

• International Journal of Oral Biology
• /
• v.36 no.4
• /
• pp.173-178
• /
• 2011

Tumor necrosis factor alpha ($TNF{\alpha}$) is a multifunctional cytokine that is elevated in inflammatory diseases such as atherosclerosis, diabetes and rheumatoid arthritis. Recent evidence has suggested that ${\beta}2$ adrenergic receptor (${\beta}2AR$) activation in osteoblasts suppresses osteogenic activity. In the present study, we explored whether $TNF{\alpha}$ modulates ${\beta}AR$ expression in osteoblastic cells and whether this regulation is associated with the inhibition of osteoblast differentiation by $TNF{\alpha}$. In the experiments, we used C2C12 cells, MC3T3-E1 cells and primary cultured mouse bone marrow stromal cells. Among the three subtypes of ${\beta}AR$, ${\beta}2$ and ${\beta}3AR$ were found in our analysis to be upregulated by $TNF{\alpha}$. Moreover, isoproterenol-induced cAMP production was observed to be significantly enhanced in $TNF{\alpha}$-primed C2C12 cells, indicating that $TNF{\alpha}$ enhances ${\beta}2AR$ signaling in osteoblasts. $TNF{\alpha}$ was further found in C2C12 cells to suppress bone morphogenetic protein 2-induced alkaline phosphatase (ALP) activity and the expression of osteogenic marker genes including Runx2, ALP and osteocalcin. Propranolol, a ${\beta}2AR$ antagonist, attenuated this $TNF{\alpha}$ suppression of osteogenic differentiation. $TNF{\alpha}$ increased the expression of receptor activator of NF-${\kappa}B$ ligand (RANKL), an essential osteoclastogenic factor, in C2C12 cells which was again blocked by propranolol. In summary, our data show that $TNF{\alpha}$ increases ${\beta}2AR$ expression in osteoblasts and that a blockade of ${\beta}2AR$ attenuates the suppression of osteogenic differentiation and stimulation of RANKL expression by $TNF{\alpha}$. These findings imply that a crosstalk between $TNF{\alpha}$ and ${\beta}2AR$ signaling pathways might occur in osteoblasts to modulate their function.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.2
• /
• pp.300-307
• /
• 1997

The effects of Aster scaber and Ixeris dentata on cadiovascular system in hyperlipidemic rats were examined. Five groups of thirty Sprague Dawley rats were fed with the diet contained 1% cholesterol, 0.25% sodium cholate, 10% coconut oil and 5% lard(control group) for 4 weeks. Each experimental diet group was added with 5% plant powder or extract of the 5% plant powder by dry weight. Contractile or relaxation responses in the isolated artria and thoracic aortae were measured and the morphological changes of the aortic endotherium from the rats fed the experimental diet were inspected. In response to isoproterenol, the number of right atrial spontaneous beat was significantly lower in Cham chyi powder group$(PP_{1})$ and Sumbagui powder group$(PP_{2})$ than control at $10^(-8)M$ concentration. The contraction forces by injection of phenylephrine and calcium in isolated thoracic aorta were significantly low in each experimental groups compared with the control. The relaxation rates by acetylcholine represented comparatively higher value in $PP_{1}$ than control. The morphological changes of endothelial cell surface was a little in $PP_{1}$ and $PP_{2}$ compared with control, while the damages were considerably advanced in Cham chyi and Sumgbagui extract diet group$(PE_{1},\;PE_{2})$.