• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.863-869
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• 2011

The aim of the present study is to investigate whether an ethanol extract of Acorus gramineus Soland (EAG) augments penile erection in vitro and in vivo experiment. Preconstructed with phenylephrine (PE) in isolated endothelium-intact rabbit corpus cavernosum, EAG relaxed penile smooth muscle in a dose-dependent manner, which was inhibited by pretreatment with NG-nitro-L-argininemethylester (L-NAME), a nitricoxide synthase inhibitor, and 1H-[1,2,4]-oxadiazole-[4,3-${\alpha}$]-quinoxalin-1-one (ODQ), a soluble guanylylcyclase (sGC) inhibitor, respectively. EAG-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA), a nonselective $K^+$ channel blocker. EAG increased cGMP levels of the rabbit corpus cavernosum in a concentration-dependent manner without changes in cAMP levels. In addition, EAG caused increase of peak intracavernous pressure (ICP), ICP/MAP ratio and area under the carve (AUC) in SD rats. Taken together, these results suggest that EAG augments penile erection via NO-cGMP system and $K^+$ channels in corpus cavernosum.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.305-309
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• 1992

Cytosine deaminase (EC 3.5.4.1) from BaciNus stc~urorhermophilus was partially purified 7.2-fold with an overall yield of 52.7%. The partially purified enzyme deiiminated cytosine only.but not 5-methylcytosine and 5-fluorocytosine. The apparent Michaclis constant. Km valuefor cytosine was 5.9 mM. The enzyme was relatively stable in the range of pH 4.0 to 7.0.furthermore extremely thermo-stable : more than 75'X) of the activity was remained afterheating at 80$^{\circ}$C for I0 min at pH 6.5. The enzyme had a pH optimum at around pH7.0 to 7.5. and temperature optimum at 35 to 31$^{\circ}$C. And the activation energ (En value)determined from an Arrhenius plot was 26 Kcal/mol. The enzyme activity was stronglyinhibited by heavy metal ions such as Cd", Hg". Cut' at 1 mM, anJ by o-phenanthroline,and p-chloromcrcuribcnzoate at I mM. But the enrymc activity was activatetl increased byGMP, and CMP at 1 mM.ased by GMP, and CMP at 1 mM.

• Molecules and Cells
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• v.21 no.3
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• pp.337-342
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• 2006

Interstitial cells of Cajal (ICCs) are pacemaker cells that activate the periodic spontaneous depolarization (pacemaker potentials) responsible for the production of slow waves in gastrointestinal smooth muscle. The effects of vasoactive intestinal polypeptide (VIP) on the pacemaker potentials in cultured ICCs from murine small intestine were investigated by whole-cell patch-clamp techniques. Addition of VIP (50 nM-$1{\mu}M$) decreased the amplitude of pacemaker potentials and depolarized resting membrane potentials. To examine the type of receptors involved in ICC, we examined the effects of the $VIP_1$ agonist and found that it had no effect on pacemaker potentials. Pretreatment with $VIP_1$ antagonist ($1{\mu}M$) for 10 min also did not block the VIP (50 nM)-induced effects. On the other hand exposure to 1H-(1,2,4)oxadiazolo(4,3-A)quinoxalin-1-one (ODQ, $100{\mu}M$), an inhibitor of guanylate cyclase, prevented VIP inhibition of pacemaker potentials. Similarly KT-5823 ($1{\mu}M$) or RP-8-CPT-cGMPS ($10{\mu}M$), inhibitors of protein kinase G (PKG) blocked the effect of VIP (50 nM) on pacemaker potentials as did N-nitro-L-arginine (L-NA, $100{\mu}M$), a non-selective nitric oxide synthase (NOS) inhibitor. These results imply that the inhibition of pacemaker activity by VIP depends on the NO-cGMP-PKG pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.273-277
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• 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 and Pharmacology
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• v.5 no.1
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• pp.93-98
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• 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.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.129-136
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• 2002

The purpose of this study was to investigate the comparison of viability of bovine blastocysts following glass micropipette (GMP) vitrification and the possibility of production of Korean Native Cow ("Hanwoo,"Bos taurus coreanae) following embryo transfer into Mongolia cows (Bos taurus mongolian). The embryos of Korean Native Cow were produced by IVMFC or superovulation methods in Korea, cryopreserved by GMP vitrification, and subsequently trans-ported to Mongolia. The recipient cows were synchronized using a CIDR plus and prostaglandin $F_2\alpha$($PGF_2\alpha$) treatment. To produce in vivo embryos, seven cows were superovulated using FSH and PGF$_2$／sub $\alpha$／ treatment. A total of 64 blastocysts ( $9.1\pm2.94$ per cow) were collected. In vitro embryos were produced using a defined culture system which cleaved in 80.1％ ova (174／217), and developed to blastocyst stage embryos of 40.8％ (71／174). The post-thaw survival rate of in vivo blastocysts (93.7％; 45／48) was significantly higher than that of in vitro blastocysts (82.5％; 52／63, P＜0.05). Embryo transfer was carried out using 8 Mongolian recipient cows and 2 post-thaw blastocysts per recipient. Five of 8 recipients were found pregnant at Day 60 but one abortion occurred by Day 240. Two of offspring were produced from the Mongolian cows at 275 days after embryo transfer. These results indicated that a GMP vitrification method could be used as a cryopreservation technique for in vivo or in vitro bovine blastocysts and produced effectively a Korean Native Cow following embryo transfer into a Mongolian recipient cow.

• Biomolecules & Therapeutics
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• v.3 no.1
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• pp.58-62
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• 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.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.379-383
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• 2000

Pathophysiological implications of the vascular nitric oxide (NO)/cGMP pathway in hypertension were investigated. Sprague-Dawley rats were made deoxycorticosterone acetate (DOCA)-salt hypertensive for six weeks. The protein expression of endothelial constitutive NO synthase (ecNOS) and the tissue content of NO were determined in the thoracic aorta. The protein expression and catalytic activity of soluble guanylyl cyclase (GC) were also determined. Systolic blood pressure measured on the day of experiment was significantly higher in the experimental group than in the control. The hypertension was associated with decreases in the vascular tissue content of NO metabolites, concomitantly with the expression of ecNOS proteins. The protein expression of GC was not affected, while its catalytic activity was significantly decreased in hypertension. These results indicate that the high blood pressure is associated with a decreased activity of vascular NO/cGMP pathway in DOCA-salt hypertension.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.21-24
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• 1991

The promoter isolated from an alkali-tolerant Hwillus sp. chromosomal DNA was subcluned. The activity of promoter in B, subtilis and alkali-tolerant Bacillus sp. began to increase at the early stage. of spore formation. In the presence of 1% glucose, the promotcr activity repressed and was recovered by ;tddition of c-GMP in the medium.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.99-111
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• 1992

Permissive action of thyroid hormone at the level of Ca channel and responsible mechanisms underlying thyroid hormone-induced change in myocardial contractile state and $T_3-induced$ arrhythmias were investigated in rabbit ventricular or atrial myocytes using whole cell patch clamp technique. Single cells were isolated by Langendorff perfusion with collagenase. Cardiac myocytes were incubated in $low-Cl^-,$, $high-K^+$ medium containing $1_{\mu}M\;L-triiodothyronine\;(T_3)$ at $4^{\circ}C$ for 2.10 hours. The calcium currrent $(I_{Ca})$ was increased in $T_3$ loaded cells, however, the shape of current voltage curve and reverse potential did not altered. Cyclic AMP, cyclic GMP, isoprenaline and 3-isobutyl-1-methyl-xanthine increased $I_{Ca}$ in euthyroid and hyperthyroid conditions, and acetylcholine blocked the increase of $I_{Ca}\;in\;T_3$ loaded cells. The amplitude of $I_{Ca}$ was much larger after perfusing cGMP than cGMP in both conditions, whereas the degree of increase of $I_{Ca}$ was greater after perfusing cAMP than cGMP in $T_3$ loaded cells. The degree of increase of $I_{Ca}$ after perfusing isoprenaline or IBMX also was greater in $T_3$ loaded cells than in control cells. Background current induced by isoprenaline also increased in $T_3$ loaded cells. The Ca release dependent inward current was increased in amplitude but its activation and inactivation time course was not changed in $T_3$ loaded cells. Activation of Na pump current was not changed in $T_3$ loaded cells. From the above results it is suggested that thyroid hormone induced increase in the contractile state of cardiac myocytes are accompanied by augmented $I_{Ca}$ and the increase of Ca release from sarcoplasmic reticulum and the permissive action of thyroid hormone to catecholamines could induce arrhythmias through the increase of $I_{Ca}$ and background current.