• The Korean Journal of Physiology and Pharmacology
• /
• 제15권5호
• /
• pp.273-277
• /
• 2011

Nitric oxide (NO) and atrial natriuretic peptide (ANP) may induce vascular relaxation by increasing the production of cyclic guanosine monophosphate (cGMP), an important mediator of vascular tone during sepsis. This study aimed to determine whether regulation of NO and the ANP system is altered in lipopolysaccharide (LPS)-induced kidney injury. LPS (10 $mg{\cdot}kg^{-1}$) was injected in the tail veins of male Sprague-Dawley rats; 12 hours later, the kidneys were removed. Protein expression of NO synthase (NOS) and neutral endopeptidase (NEP) was determined by semiquantitative immuno-blotting. As an index of synthesis of NO, its stable metabolites (nitrite/nitrate, NOx) were measured using colorimetric assays. mRNA expression of the ANP system was determined by real-time polymerase chain reaction. To determine the activity of guanylyl cyclase (GC), the amount of cGMP generated in response to sodium nitroprusside (SNP) and ANP was calculated. Creatinine clearance decreased and fractional excretion of sodium increased in LPS-treated rats compared with the controls. Inducible NOS protein expression increased in LPS-treated rats, while that of endothelial NOS, neuronal NOS, and NEP remained unchanged. Additionally, urinary and plasma NOx levels increased in LPS-treated rats. SNP-stimulated GC activity remained unchanged in the glomerulus and papilla in the LPS-treated rats. mRNA expression of natriuretic peptide receptor (NPR)-C decreased in LPS-treated rats, while that of ANP and NPR-A did not change. ANP-stimulated GC activity reduced in the glomerulus and papilla. In conclusion, enhancement of the NO/cGMP pathway and decrease in ANP clearance were found play a role in the pathogenesis of LPS-induced kidney injury.

• The Korean Journal of Physiology
• /
• 제26권1호
• /
• pp.15-25
• /
• 1992

In order to elucidate the properties of the background current whole cell patch clamp studies were performed in rabbit ventricular cells. Ramp pulses of ${\pm}80\;mV$ from holding potential of 40 mV(or 20 mV) at the speed of 0.8 V/sec were given every 30 sec(or 10 sec) and current-voltage diagrams(I-V curve) were obtained. For the activation of the background current isoprenaline, adenosine 3',5'-cyclic monophosphate(dBcAMP), guanosine 3',5'-cyclic monophosphate(cGMP), and $N^6$-2'-o-dibutyryladenosine 3',5'-cyclic monophosphate(dBcAMP) were applied after all known current systems were blocked with 2mM Ba, 1 mM Cd ,5 mM Ni, 10 ${\mu}M$ diltiazem, 10 ${\mu}m$ ouabain, and 20 mM tetraethylammonium(TEA). The conductance of background current in control was $0.65{\pm}0.69$ nS at 0 mV, its I-V curves was almost linear and reversed near 50 mV. When there was no taurine in pipette solution, isoprenaline hardly activated the background current but when taurine existed in pipette solution, isoprenaline activated the larger background current. Cyclic AMP or cyclic GMP alone had little effect on the activation of the background current, while cGMP potentiated cGMP effect. When the background current was activated with cGMP and cAMP, isoprenaline could not further increased the background current. The background current activated by isoprenaline depended on extracellular $Cl^-$ concentration and its reversal potential was shifted according to chloride equilibrium potential. The change of extracellular $Na+$ concentration had little effect on reversal potential of the background current activated by isoprenaline.

• The Korean Journal of Physiology and Pharmacology
• /
• 제5권1호
• /
• pp.93-98
• /
• 2001

The precise mechanism of set-point regulation in hypothalamus was not elucidated. Nitric oxide synthases(NOS) were detected in hypothalamus, however, the roles of NO in hypothalamus was not fully studied. So, we tested the effects of NO on body temperature because preoptic-anterior hypothalamus was known as the presumptive primary fever-producing site. NO donor sodium nitroprusside (SNP, 4 nmol, i.c.v.) elicited marked febrile response, and this febrile response was completely blocked by indomethacin (a cyclooxygenase inhibitor). But, ODQ (selective guanylate cyclase inhibitor, $50\;{\mu}g,$ i.c.v.) did not inhibit fever induced by SNP. The cyclic GMP analogue dibutyryl-cGMP $(100\;{\mu}g,\;i.c.v.)$ induced significant pyreses, which is blocked by indomethacin. $N^G-nitro-L-arginine$ methyl ester (L-NAME, non selective NOS inhibitor) inhibited fever induced by $interleukin-1{\beta}\;(IL-1{\bata},\;10\;ng,\;i.c.v.),$ one of endogenous pyrogens. These results indicate that NO may have an important role, not related to stimulation of soluble guanylate cyclase, in the signal pathway of thermoregulation in hypothalamus.

• Biomolecules & Therapeutics
• /
• 제3권1호
• /
• pp.58-62
• /
• 1995

We investigated whether nitric oxide (NO) may serve a role in bladder function by immunohistochemical analysis of the distribution of intrinsic NADPH-diaphorase and functional study of isometric tension recordings via a photo-induced adequate nitric oxide (PIANO) generating system using rat bladder. Results suggest that a small number of NADPH-diaphorase-positive perikarya are present within the bladder wall and within adjacent small ganglia. Furthermore, NADPH-diaphorase-positive nerve fibers were observed in the adventitial and muscular layers, subjacent to the urothelium and perivascular fibers. Rat bladder strips precontracted with 3$\mu$M carbachol were reversibly relaxed upon NO generation by UV irradiation. PIANO-mediated relaxation was sensitive to oxygen free radicals. In addition, tissue cGMP levels were increased by the PIANO generating system and elevated cGMP levels were decreased by pretreatment of guanylate cyclase inhibitor, methylene blue. These results indicate that NO may serve a role in modulating bladder tone in the rat.

• 대한약리학회지
• /
• 제19권1호
• /
• pp.93-99
• /
• 1983

Hydrocortisone 5 mg/kg which exerts minimal effect on the renal function and furosemide 1 mg/kg which induces moderate amount of diuresis were injected intraperitoneally to study their effects on the renal cyclic nucleotides content in rats. 1) The renal tissue levels of cAMP were significantly increased by administration of hydrocortisone, but there was no significant change in the furosemide group compared with that of saline treated control group. Moderate elevation in renal cAMP level was noted by the combined administration of hydrocortisone and furosemide, but this elevation was less than that of hvdrocortisone treated group. 2) The renal cGMP level did not show nay remarkable change after the administration of hydrocortisone, however, there were a significant increase by the administration of furosemide alone or combination of both drugs. The level of renal cGMP was higher and maintained longer in the combined treated group than furosemide treated group. The result of this experiment indicates that the potentiating effect of hydrocortisone on the diuretic action of furosemide nay be related to the renal levels of cGMP rather than that of cAMP.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
• /
• 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.

• 한국식품과학회지
• /
• 제21권1호
• /
• pp.145-148
• /
• 1989

건조표고버섯의 품질을 향상시키기 위해 열풍, 원적외선 및 냉동 건조시 건조조건이 품질에 미치는 영향에 대해 조사하였다. $45-70^{\circ}C$ 범위에서 열풍건조시 온도가 증가할수록 부피유지율은 높았으나 복수율은 낮았으며 5'-GMP 함량은 $50^{\circ}C$에서 건조한 것이 가장 많았다. 원적외선 전조는 같은 온도에서의 열풍건조에 비해 복수율은 높았으나 부피유지율이 낮았다. 냉동건조시 냉동속도에 따른 부피유지율의 차이는 뚜렷하지 않았지만 복수율은 $-18^{\circ}C$에서 냉동시킨 것이 가장 높았으며 건조속도에 의한 영향은 건조속도가 빠를수록 복수율이 증가하였다. 또한 냉동속도와 건조속도가 빠를수록 5'-AMP, 5'-GMP 와 5'-XMP 함량이 모두 증가하는 경향이었다.

• The Korean Journal of Physiology and Pharmacology
• /
• 제2권2호
• /
• pp.217-223
• /
• 1998

Oxygen-derived free radicals have been implicated in many important functions in the biological system. Electrical field stimulation (EFS) causes arterial relaxation in animal models. We found that EFS applied to neither muscle nor nerve but to Krebs solution caused a relaxation of rat aorta that had been contracted with phenylephrine. In the present study, therefore, we investigated the characteristics of this EIRF (electrolysis-induced relaxing factor) using rat isolated aorta. Results indicated that EIRF acts irrespective of the presence of endothelium. EIRF shows positive Griess reaction and is diffusible and quite stable. EIRF-induced relaxation was stronger on PE-contracted aorta than on KCl-contracted one, and inhibited by the pretreatment with methylene blue. Zaprinast, a cGMP-specific phosphodiesterase inhibitor, potentiated the EIRF-induced relaxation. $N^G-nitro-L-arginine$, NO synthase inhibitor, did not inhibit the EIRF-induced relaxation. Deferroxamine, but not ascorbic acid, DMSO potentiated the EIRF-induced relaxation. These results indicate that electrolysis of Krebs solution produces a factor that relaxes vascular smooth muscle via cGMP-mediated mechanism.

• 한국식품위생안전성학회:학술대회논문집
• /
• 한국식품위생안전성학회 2002년도 춘계학술발표대회 및 심포지움
• /
• pp.137-137
• /
• 2002

Several epidemiologidal studies suggested that arsenic exposure was strongly correlated with the development of cardiovascular disease such as hypertension. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation using the isolated rat aortic ring in in vitro organ bath system. Treatment with arsenite inhibited acetylcholine-induced relaxation of aortic rings in a concentration- dependent manner. The inhibitory effects by arsenic were also observed in the relaxation induced by sodium nitroprusside, a NO-donor. Consistent with these findings, the cGMP levels stimulated by acetylcholine in blood vessels were reduced significantly by arsenite treatment. In addition, higher concentration of arsenite decreased the relaxation by 8-Br-cGMP, a cGMP analog, in aortic rings without endothelium. These in vitro results indicated that arsenite that arsenite was capable of suppressing acetylcholine-induced relaxation in blood vessels by inhibiting production of nitric oxide in endothelial cells and by impairing the relaxation machinary in smooth muscle cells. In vivo studies revealed that the reduction of blood pressure by acetylcholine infusion was signigicantly suppressed after arsenite was administered intravenously to rate. These data suggest that vasomotor tone impaired by arsenite exposure may be one of the contrbuting factors in development of cardiovascular disease.

• 동의생리병리학회지
• /
• 제23권2호
• /
• pp.389-396
• /
• 2009

The ethanol extract of Persicaria perfoliata (EPP) induced relaxation of the phenylephrine-precontracted aorta in a dose-dependent manner, which was abolished by removal of functional endothelium. Pretreatment of the aortic tissues with NG-nitro-L-arginine methyl ester (L-NAME) or 1H-[1,2,4}-oxadiazole-[4,3-${\alpha}$)-quinixalin-1-one (ODQ) inhibited the relaxation induced by EPP. However, EPP-induced relaxation was not blocked by pretreatment with indomethacine, glibenclamide, tetraethylammonium (TEA), atropine, or propranolol. Incubation of endothelium-intact thoracic aortic ring with EPP increased the production of cGMP, which was also blocked by pretreatment with L-NAME or ODQ. These results suggest that EPP dilates vascular smooth muscle via endothelium-dependent NO/cGMP signaling.