• Journal of the Korean Society of Food Science and Nutrition
• /
• v.29 no.2
• /
• pp.329-334
• /
• 2000

Two major oleananesaponins in Bupleuri radix, saikosaponin $\alpha$ and d, were extracted at various solvent compositions and leaching temperatures. Solvent composition was varied at 0 to 100%(v/v) of ethanol-water and methanol-water, whereas leaching temperature was adjusted to te range of 25~45$^{\circ}C$. The most effective extractant and leaching temperature were 70% ethanol and 45$^{\circ}C$, respectively. However, no major differences in saikosaponin content and cAMP phosphodiesterase inhibition were found at various leaching times. The cAMP phosphodiesterase inhibitions were alo the highest when 70% ethanol was used as the extractant.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.9
• /
• pp.2707-2710
• /
• 2013

The present communication deals with development of ten novel N-Phenyl-3-Pyridin-2-yl imino derivatives as vascular smooth muscle relaxants. The derivatives were prepared and optimized using pocket modelling and pharmacophore modelling. The 4 hydroxy substituted derivatives are showed potent activity comparable to the sildenafil.

• Korean Journal of Veterinary Research
• /
• v.43 no.4
• /
• pp.615-624
• /
• 2003

Vascular smooth muscle relaxation is modulated by an increase in cGMP subsequent to nitric oxide (NO) production by endothelial cells. The effects of cAMP and cGMP phosphodiesterase (PDE) inhibitors were investigated in phenylephrine-precontracted rat aorta rings by using the specific inhibitors of PDE I, III, IV and V as relaxing agents (calmodulin-activated PDE inhibitors, IBMX and $W_7$, type I; cAMP-specific PDE inhibitors, milrinone, type IV; Ro 20-1724, type III and cGMP-specific PDE inhibitor, zaprinast, type V). All the PDE inhibitors produced a concentration-dependent relaxation in the ring with intact endothelium (+E). Except for milrinone, all the PDE inhibitors-induced relaxations were inhibited by removal of extracellular $Ca^{2+}$, $N^G$-nitro-L-arginine, $N^G$-nitro-L-arginine methyl ester, methylene blue (MS) or nifedipine. The specific PDE I and PDE IV inhibitors both produced endothelium-independent relaxations which were inhibited by MS in -E rings. However, zaprinast had no effect in -E rings. Except for milrinone, sodium nitroprusside (a NO donor)-induced relaxation was significantly augmented by all PDE inhibitors in +E rings. The results suggest that I) the vasorelaxant properties of IBMX, $W_7$, Ro 20-1724 and zaprinast are dependent on endothelium or on interaction with $Ca^{2+}$ regulation, 2) each PDE is differently distributed in vascular tissues (endothelial and smooth muscle cells), 3) the vasodilations of PDE inhibitors are due to the increase of cAMP and cGMP formation through inhibition of cAMP- and cGMP-PDE and 4) the vasodilation action of milrinone does not involve in endothelial-cyclic nucleotide system.

• Journal of Korean Neurosurgical Society
• /
• v.52 no.1
• /
• pp.32-36
• /
• 2012

Objective : Alcoholic neuropathy is characterized by allodynia (a discomfort evoked by normally innocuous stimuli), hyperalgesia (an exaggerated pain in response to painful stimuli) and spontaneous burning pain. The aim of the present study is to investigate the effect of rolipram, a phosphodiesterase 4 inhibitor, against alcohol-induced neuropathy in rats. Methods : Allodynia was induced by administering 35% v/v ethanol (10 g/kg; oral gavage) to Spraue-Dawley rats for 8 weeks. Rolipram and saline (vehicle) were administered intraperitoneally. Mechanical allodynia was measured by using von Frey filaments. Somatosensory evoked potential (SEP) was proposed as complementary measure to assess the integrity of nerve pathway. Results : The ethanol-induced mechanical allodynia began to manifest from 3 week, and then peaked within 1 week. Beginning from 3 week, latency significantly started to increased in control group. In rolipram treated rats, the shorter latency was sustained until 8 weeks (p<0.05). The mechanical allodynia, which began to manifest on the 3 weeks, intraperitoneal injections of rolipram sustained statistical difference until 8 weeks, the final week of the study (p<0.05). Conclusion : This study suggests that rolipram might alleviate mechanical allodynia induced by alcohol in rats, which clearly has clinical implication.

• Archives of Pharmacal Research
• /
• v.25 no.6
• /
• pp.873-878
• /
• 2002

OA-8159, a new Phosphodiesterase (PDE) 5 inhibitor, has exhibited potent erectogenic potential in a penile erection test in rats and anesthetized dogs. In this study, we investigated the mechanism of its erectogenic activity by measuring the activity of OA-8159 against a various PDE isozymes and assessing cGMP and cAMP formation in a rabbit corpus cavernosum in vitro. DA-8159 inhibited the PDE 5 activity in rabbit and human platelets, which the $IC_{50}$ was 5.84$\pm$1.70 nM and 8.25$\pm$2.90 nM, respectively. The $IC_{50}$ of DA-8159 on PDE 1, PDE2, PDE 3 and PDE 6 were 870$\pm$57.4 nM, $101\pm$5 $\mu$M, 52.0$\pm$3.53 $\mu$M and 53.3$\pm$2.47 nM, respectively. This suggests that DA-8159 is a potent, highly selective, competitive inhibitor of PDE 5-catalyzed cGMP hydrolysis. The rates of cGMP hydrolysis catalyzed by human platelets-derived PDE 5 as a function of the cGMP concentration (5~100 nM) and two-fixed DA-8159 concentration (11.3 and 18.8 nM) were investigated in order to characterize the mode of PDE 5 inhibition by DA-8159. DA-8159 increased the apparent 4K_{m}$ value for cGMP hydrolysis but had no effect on the apparent $V_{max}$, indicating a competitive mode of inhibition. DA-8159 increased the cGMP concentrations in the rabbit corpus cavernosum dose dependently. In the presence of sodium nitroprusside (SNP), DA-8159 significantly sti\mulated the accu\mulation of cGMP when compared to the control level. This indicated that the enhancement of a penile erection by DA-8159 involved the relaxation of the cavernosal smooth \muscle by NO-sti\mulated cGMP accu\mulation. In conclusion, DA-8159 is a selective inhibitor of PDE 5-catalyzed cGMP hydrolysis and the enhancement of a penile erection by DA-8159 is mediated by the relaxation of the cavernosal smooth \muscle by the NO-sti\mulated cGMP accu\mulation.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.5
• /
• pp.402-407
• /
• 2006

Vascular endothelial cells release proteinases that degrade the extracellular matrix (ECM), thus enabling cell migration during angiogenesis and vasculogenesis. Sildenafil citrate stimulates the nitric oxide-cyclic guanosine monophosphate pathway through inhibition of phosphodiesterase type V (PDE5). In this report, we examined the mechanisms underlying sildenafil citrate-induced cell migration using cultured mouse aortic endothelial cells (MAECs). Sildenafil citrate induced migration and proteinase secretion by murine endothelial cells. Sildenafil citrate induced the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9, which is inhibited by $NF-{\kappa}B$ inhibitors. Sildenafil citrate also induced the secretion of plasmin, which is inhibited by PI 3'-kinase inhibitors. It is suggested that sildenafil citrate-induced migrating activity in endothelial cells may be accomplished by increased secretion of proteinases.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.245.1-245.1
• /
• 2003

DA-8159 is a new PDEV (Phosphodiesterase V) inhibitor, synthesized by Dong-A Pharm., as an oral agent to treat male erectile dysfunction. To make a selection of the dosage of oral administration in carcinogenic studies, we studied preliminarily the pharmacokinetics of DA-8159 after single (at the 1$\^$st/ day) and 1-week (at the 7$\^$th/ day) oral administrations of the drug at doses of 15, 50 and 150 mg/kg/day, to male ICR mice. In 15mg/kg single and 1-week repeated oral administration groups, the concentrations of DA-8159 and DA-8164(the main metabolite of DA-8159) were below the limit of quantitation(LOQ:50ng/ml). (omitted)

• Journal of Chest Surgery
• /
• v.25 no.4
• /
• pp.364-382
• /
• 1992

In order to investigate the effect of intracellular cyclic GMP on the calcium channel, whole cell patch clamp technique with internal perfusion method was used in the single ventricular myocytes of the rabbit. Cyclic GMP, cGMP analogues, cAMP, isopernaline and forskolin were perfused into cells and their effects on the calcium current were analysed by applying depolarizing step pulse of 10 mV in amplitude for 200 msec from holding potential of -40 mV. Calcium currents usually activated from -30 mV and then reached a peak at +10 mV. Amplitude of the calcium current was standardized with membrane capacitance, 50 pF. Peak amplitude at +10 mV in control was -0.15 nA/50pF. When 100 mM cAMP was applied from the pipette, peak amplitude of calcium current increased to -0.32 nA and addition of 1 mM isoprenaline further increased its amplitude. In the presence of cGMP it alone also produced an increase of the calcium current to -0.52 nA/50pF and addition of isoprenaline or forskolin increased its magnitude to -[0.55~0.95] nA/50pF. Simultaneous application of cGMP and cAMP increased the calcium current to -0.67 nA/50pF. Among the cGMP analogues, 8-Br-cGMP was the most potent stimulant for the calcium current activation. From the above results it could be concluded tlat cGMP increases the calcium current not through cAMP dependent protein kinase nor cAMP dependent phosphodiesterase pathway, but through independent phosphorylation pathway, possibly cGMP dependent protein kinase pathway.

• Korean Journal of Pharmacognosy
• /
• v.30 no.4
• /
• pp.377-383
• /
• 1999

The anti-asthmatic activities of the extract of Lonicera japonica (BuOH fraction) and its mode of action were investigated using several in vitro and in vivo models. Lonicera japonica was extracted with 30% ethanol (v/v) and successively partitioned into BuOH. The BuOH fraction reduced antigen-induced contraction of isolated trachea from sensitized guinea pigs in a concentration-dependent manner. The BuOH fraction also inhibited histamine release from rat peritoneal mast cells induced by antigen or calcium ionophore A23187 ($IC_{50}=0.26$ and 0.32mg/ml, respectively). Eosinophil infiltration into bronchoalveolar lavage fluids induced by aeroallergen challenge in passively sensitized guinea pigs was inhibited by the BuOH fraction at a dose of 800mg/kg (51.7%). In addition, the BuOH fraction inhibited leukotriene $B_4$ prodution in rat basophilic leukemia cells ($IC_{50}=0.42\;mg/ml$) as well as phosphodiesterase 4 (PDE4) isolated from rat brain ($IC_{50}=0.015\;mg/ml$). All results from this study strongly suggest that the BuOH fraction of Lonicera japonica may be useful in the treatment of asthma and its mode of action may be related with inhibition of both 5-lipoxygenase and PDE4 enzyme.

• Korean Journal of Veterinary Research
• /
• v.22 no.1
• /
• pp.1-8
• /
• 1982

The effect of acetylcholine, oxytocin and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on cyclic nucleotide levels in estrogen-primed rabbit whole uterus were studied in the presence and absence of 1-methyl-3-isobutyl xanthine (MIX), a phosphodiestrase inhibitor, and indomethacin, a prostagandin inhibitor. In the absence of MIX, acetylcholine increased guanosine 3', 5'-cyclic monophosphate (cGMP), but had no effect on adenosine 3', 5'-cyclic monophosphate (cAMP) levels. In contrast, oxytocin had no influence on cGMP, but decreased cAMP levels. $PGF_{2{\alpha}}$ increased cGMP and decreased cAMP levels. MIX increased both cAMP and cGMP levels. Oxytocin and $PGF_{2{\alpha}}$ further increased cGMP levels, indicating activation of guanylate cyclase activity. The ratio of cAMP/cGMP was decreased by uterine stinulants both in presence and absence of MIX. Indomethacin elevated cAMP and cGMP revels. The effects of uterine stimulants in the presence of indomethacin on cyclic nucleotide levels were varied from tissue to tisse. In general, oxytocin decreased cGMP and $PGF_{2{\alpha}}$ increased cAMP/cGMP levels, but the effects were statisically nonsignicficant. The cAMP/cGMP ratio was increased by uterine stimulant in the presence of indomethacin. In conclusion, uterine stimulants eased cAMP/cGMP ratio which indicates that the uterine stimulants have opposing effects on adenylate cyclase and guanylate cyclase activities. The endometrium plays a role in the regulation of cyclic nucleotide levels and uterine contraction by means of PG synthesis. Indomethacin has an unknown activities besides both of PG synthetase and phosphodiesterase inhibitions.