• Proceedings of the Korean Biophysical Society Conference
• /
• 2002.06b
• /
• pp.15-15
• /
• 2002

Cyclic nucleotide phosphodiesterases (PDEs) regulate physiological processes by degrading ubiquitous intracellular second messengers, cAMP or cGMP. The first crystal structure of PDE4D catalytic domain and a bound inhibitor, zardaverine, was determined. Zardaverine binds to a highly conserved pocket that includes the catalytic metal binding site.(omitted)

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.158-158
• /
• 2015

Myoblast are myogenic precursors that proliferate, activate, and differentiate on muscle injury to sustain the regenerative capacity of skeletal muscle; The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for Nitric oxide (NO) in muscle biology1,2,3. However, the expression and subcellular localization of NO in muscle development and myoblast differentiation are largely unknown. In this study, we examined effects of the nitric oxide generated by a microwave plasma torch, on proliferation/differentiation of rat myoblastic L6 cells. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimetres per minute. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the ratio of oxygen gas, and the microwave power4. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to L6 skeletal muscles. Differentiation of L6 cells into myotubes was significantly enhanced the differentiation after nitric oxide treatment. Nitric oxide treatment also increase the expression of myogenesis marker proteins and mRNA level, such as myogenin and myosin heavy chain (MHC), as well as cyclic guanosine monophosphate (cGMP), However during the myotube differentiation we found that NO activate oxidative stress signaling erks expression. Therefore, these results establish a role of NO and cGMP in regulating myoblast differentiation and elucidate their mechanism of action, providing a direct link with oxidative stress signalling, which is a key player in myogenesis. Based on these findings, nitric oxide generated by plasma can be used as a possible activator of cell differentiation and tissue regeneration.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.6
• /
• pp.673-679
• /
• 1997

It has been generally accepted that glutamate mediates the ischemic brain damage, excitotoxicity, and induces release of neurotransmitters, including norepinephrine(NE), in ischemic milieu. In the present study, the role of nitric oxide(NO) in the ischemia-induced $[^3H]norepinephrine([^3H]NE)$ release from cortex slices of the rat was examined. Ischemia, deprivation of oxygen and glucose from $Mg^{2+}-free$ artificial cerebrospinal fluid, induced significant release of $[^3H]NE$ from cortex slices. This ischemia-induced $[^3H]NE$ release was significantly attenuated by glutamatergic neurotransmission modifiers. $N^G-nitro-L-arginine$ methyl ester(L-NAME), $N^G-monomethyl-L-arginine$ (L-NMMA) or 7-nitroindazole, nitric oxide synthase inhibitors attenuated the ischemia-evoked $[^3H]NE$ release. Hemoglobin, a NO chelator, and 5, 5- dimethyl-L-pyrroline-N-oxide(DMPO), an electron spin trap, inhibited $[^3H]NE$ release dose-dependently. Ischemia-evoked $[^3H]NE$ release was inhibited by methylene blue, a soluble guanylate cyclase inhibitor, and potentiated by 8-bromo-cGMP, a cell permeable cGMP analog, zaprinast, a cGMP phosphodiesterase inhibitor, and S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide generator. These results suggest that the ischemia-evoked $[^3H]NE$ release is mediated by NMDA receptors, and activation of NO system is involved.

• Korean Journal of Animal Reproduction
• /
• v.20 no.4
• /
• pp.385-393
• /
• 1997

다세포 생물에서 몸의 효율적 생존을 위한 각 기관의 homeostasis는 세포 증식과 사망에 의해 조절된다. 따라서, apoptosis라 명명된 세포사망은 정교한 기전에 의한 능동적이고 자발적인 사망기전으로써 몸의 정상적 유지를 위한 필수적인 현상이다. 발생기 세포나 신경세포 또는 흉선세포 분화 동안 과다한 세포의 제거가 apoptosis의 대표적인 예이며, 각종 호르몬에 의해 그 기능이 조절되는 난소세포에서도 apoptosis가 활발히 일어난다. Rat난소에는 태어날 때 수십 만개의 난포를 지니고 있는데, 이 중 단지 1%만이 배란에 사용되어질 뿐이고 나머지는 모두 사망하게 된다. 이러한 난포사망은 난소의 적절한 세포 수를 유지하기 위한 필수적 과정이며, 인위적으로 apoptosis를 억제하는 유전자인 bcl-2를 과다 발현시키면 난소암이 발생하는 연구결과가 이를 입증해주고 있다. 이처럼 중요한 난포 사망기전은 apoptosis라는 개념이 정립되면서 최근 들어 점차 그 연구가 활발해지고 있다. Apoptosis의 특징 중 뚜렷한 점은 DNA가 일정한 간격으로(180∼200 bp)잘려지는 DNA fragmentation현상으로, 이를 이용하여 DNA3'-end 부위에 방사선동위원소를 label한 후 이를 전기영동으로 분리하면 apoptosis를 손쉽게 측정할 수 있다. 난소의 기능은 시상하부호르몬인 LH와 FSH 뿐만 아니라 난소에서 분비되는 각종 난소국부호르몬들에 의해 조절된다. 특정한 발육단계의 난포는 특정한 호르몬에 의해 그 기능을 조절 받는데, 이러한 난소기능 조절기작은 매우 복잡한 경로를 지니고 있다. 이러한 복잡한 기작으로 인해 초기 연구에서첨 생체 내에서 밝히려는 연구 시도는 어려움에 부딪치게 되었다. 생체내 실험은 난소가 다양한 발육단계의 난포를 동시에 지니고 있어 특정한 발육단계의 난포 사망기전을 연구하기 어렵다. 또한 난포는 생체 내에서 다양한 호르몬을 동시에 분비하기 때문에 특정한 난소국부호르몬이 사망기전에 미치는 영향을 조사하기 힘든 점이 있다. 최근 들어 난포체외배양이 다양하게 개발되면서, 이러한 어려운 점을 극복할 수 있게 되었다. 본 논문은 각 발육단계의 난포를 절단해 체외배양하면서, apoptosis DNA 절단 현상을 이용하여 각종 난소국부 호르몬들이 난포발육단계별로 사망기전에 미치는 영향을 요약해 보였다. 난포는 발육하면서 점차 복잡한 호르몬 경로를 생존을 위해 필요로 한다. Prevulatory난포생존에 필요한 난소국부호르몬들은 early antral 단계의 난포에서는 그 미치는 영향이 감소되다가 preantral단계의 난포에서는 영향을 전혀 미치지 못했다. 단지 예외는 cGMP처리로써, 세포내 cGMP수준을 일정하게 유지시켜주는 것이 난포발육단계에 무관하게 생존에 중요한 인자로, 장래 연구는 난포 세포내의 cGMP수준을 조절하는 기작을 규명하는데 있을 것이다.

• Korean Journal of Pharmacognosy
• /
• v.37 no.2 s.145
• /
• pp.67-73
• /
• 2006

The butanol extracts of Agrimonia pilosa (BAP) induced dose-dependent vascular relaxation of phenylephrine-precontracted aorta, which was abolished by removal of functional endothelium. Pretreatment of the endothelium-intact aortic tissues with $N^G$-nitro-L-arginine methyl ester (L-NAME) and 1H-[1,2,4]-oxadiazole-[$4,3-{\alpha}$]-quinoxalin-1-one(ODQ) inhibited the relaxation induced by BAP. BAP-induced vascular relaxation was also markedly attenuated by addition of verapamiI, while the relaxant effect of BAP was not blocked by indomethacine, glibenclamide, tetraethylammonium (TEA), atropine, or propranolo. In addition, incubation of endothelium-intact aortic rings with BAP increased the vascular production of cGMP. These results suggest that BAP relaxes vascular smooth muscle via endothelium-dependent nitric oxide/cGMP signaling pathway, which may be causally related with L-type $Ca^{2+}$ channels.

• Herbal Formula Science
• /
• v.17 no.2
• /
• pp.175-186
• /
• 2009

The vasorelaxant effect of an extract of Lophatherum gracile Brongn (ELB) and its possible action mechanism were ascertained in aortic tissues isolated from rats. ELB relaxed endothelium-intact thoracic aorta in a dose-dependent manner. However, the induced vascular relaxation was abolished by removal in endothelium of the thoracic aorta. Pretreatment of endothelium-intact vascular tissues with $N^G$-nitro-L-arginine methyl ester (L-NAME) or 1H-[1,2,4]-oxadiazole-[4,3-$\alpha$]-quinoxalin-1-one (ODQ) significantly inhibited vascular relaxation induced by ELB. Moreover, ELB significantly increased cGMP production in aortic tissues, which was blocked by pretreatment with L-NAME or ODQ. The vasorelaxant effect of ELB was attenuated by tetraethylammonium (TEA), and glibenclamide. ELB-induced vasorelaxation was not blocked by atropine, propranolol, indomethacin, verapamil, and diltiazem. Taken together, the present study demonstrates that ELB dilates vascular smooth muscle via an endothelium-dependent NO-cGMP signaling pathway, which may be at least in part related with the function of $K^+$ channels.

• Korean Journal of Veterinary Research
• /
• v.44 no.3
• /
• pp.357-366
• /
• 2004

We studied the effect of propofol (PPF) on the endothelium-dependent vascular responses in isolated rat thoracic aorta. In aortic rings with endothelium, PPF inhibited the phenylephrine (PE)-induced contraction in a concentration-dependent manner. In PE-precontracted preparations, PPF attenuated the endothelium-dependent relaxation by acetylcholine but not by A23187. And PPF did not attenuate the endothelium-independent relaxation by sodium nitroprusside (SNP). The relaxation induced by acetylcholine in PE-precontracted aortic rings was significantly augmented by zaprinast, a cGMP-specific phosphodiesterase inhibitor, and this augmentation was inhibited by PPF. Although SNP-induced relaxation was significantly augmented by zaprinast, this augmentation was not inhibited by PPF. In preparations preconstricted with PE, the PPF-induced relaxation was inhibited by atropine. In addition, PPF attenuated the vasorelaxation by phosphodiesterase inhibitors (IBMX, Ro20-1724 or zaprinast except milrinone). In vivo, the infusion of acetylcholine and SNP showed decreased arterial blood pressure in rats. The pre-injection of PPF inhibited the acetylcholine-induced blood pressure lowering, but not the SNP-induced blood pressure lowering. These results suggest that PPF can attenuate in part the acetylcholine-induced vasorelaxation and blood pressure lowering through the inhibition of the acetylcholine receptor-mediated endothelium-derived relaxing factor by acting on endothelium. It is considered that the inhibitory effect of PPF on the vasorelaxation is due to the decreased level of cGMP which can be attributed to the inhibition of the muscarinic receptor and/or receptor-G-protein interaction.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.20 no.5
• /
• pp.1166-1173
• /
• 2006

The aqueous extracts of Cortex Caryophylli (AEC) induced dose-dependent relaxation of phenylephrine-precontracted aorta, which was abolished by removal of functional endothelium. Pretreatment of the endothelium-intact aortic tissues with N$^G$_nitro-L-arginine methyl ester (L-NAME) or 1 H-[1,2,4]-oxadiazole-[4,3-${\alpha}$l-quinoxalin-1-one (ODQ) inhibited the relaxation induced by AEC. AEC-induced vascular relaxations were also markedly attenuated by addition of verapamil, diltiazem and glibenclamide, tetraethylammonium (TEA), respectively, while the relaxation effect of AEC was not blocked by indomethacin, atropine, or propranolol. Moreover, incubation of endothelium-intact aortic rings with AEC increased the production of cGMP. These results suggest that AEC dilates vascular smooth muscle via endothelium-dependent nitric oxide/cGMP signaling, which seems to be causally related with L-type Ca$^{2+}$ and K$^+$ channels.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.9
• /
• pp.1115-1120
• /
• 2006

The effect of cinnamon ethanol extract (CN) on HT-29 cancer cell line has been examined. CN inhibited the growth of HT-29 colon cancer cells in a concentration and time dependent manner but not the growth of CCD-112CoN normal colon cells. And CN markedly inhibited the production of $PGE_2$ and cGMP as well as the mRNA expression of COX-2. These data suggest that non toxic concentration of CN has a significant inhibition effect on the growth of HT-29 cells, probably through the inhibition of $PGE_2$ production via COX-2 inhibition, and may have value as a safe chemopreventive agent for colon cancer.

• Archives of Pharmacal Research
• /
• v.24 no.6
• /
• pp.607-612
• /
• 2001

Endogenous carbon monoxide (CO) shares with nitric oxide (NO) a role as a putative neural messenger in the brain. Both gases are believed to modulate CNS function via an increase in cytoplasmic cGMP concentrations secondary to the activation of soluble guanylate cyclase (sGC). Recently CO and NO were proposed as a possible mediator of febrile response in hypothalamus. NO has been reported to activate both the constitutive and inducible isoform of the cyclooxygenase (COX). Thus, we investigated whether CO arising from heme catabolism by heme oxygenate (HO) is involved in the febrile response via the activation of COX in the hypothalamus. $PGE_2$ which is a final mediator of febrile response released from primary cultured hypothalamic cells was taken as a marker of COX activity. $PGE_2$ concentration was measured with EIA kits. Exogenous CO (CO-saturated medium) and hemin (a substrate and potent inducer of HO) evoked an increase in $PGE_2$ release from hypothalamic cells, and these effects were blocked by methylene blue (an inhibitor of sGC). And membrane permeable cGMP analogue, dibutyryl-cGMP elicited significant increases in $PGE_2$release. These results suggest that there may be a functional link between HO and COX enzymatic activities. The gaseous product of hemin through the HO pathway, CO, might play a role through the modulation of the COX activity in the hypothalamus.