• Biomolecules & Therapeutics
• /
• v.23 no.3
• /
• pp.233-237
• /
• 2015

Shikonin, a natural flavonoid found in the roots of Lithospermum erythrorhizon, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of shikonin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Shikonin significantly relaxed fluoride-, thromboxane $A_2$- or phorbol ester-induced vascular contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, shikonin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1 and the inhibition of MEK activity and the subsequent phosphorylation of ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of shikonin on agonist-induced vascular contraction regardless of endothelial function.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.97-97
• /
• 2001

This Study was attempted to investigate tile effect of dopamine, SKF 81297, a dopamine D$_1$-receptor agonist, and TNPA, a dopamine D$_2$-receptor agonist, on the blood pressure in rat. Dopamine exhibited the hypertensive action in proportion to the doses of 1.0, 3.0 arid 10.0 $\mu\textrm{g}$/kg i.v., these hypertensive action of dopamine was blocked significantly by SCH 23390, a dopamine D$_1$-receptor antagonist, on the other hand, more potentiated by raclopride, a dopamine D$_1$-receptor antagonist. SKF 81297 produced hypertensive action in a dose of 1.0 $\mu\textrm{g}$/kg i.v., wherease hypotensive action in proportion to administered doses 3.0 and 10.0 $\mu\textrm{g}$/kg i.v., these hypertensive action of SKF 81297 in a dose of 1.0 $\mu\textrm{g}$/kg i.v. was not influenced by SCH 23390 or raclopride, but hypotensive action of SKF 81297 in tile doses of 3.0 and 10.0 $\mu\textrm{g}$/kg i.v. was weakened significantly by SCH 23390, but more strenthened by raclopride. TNPA showed the hypotensive action in inverse proportion to administered doses of 1.0, 3.0 and 10.0 $\mu\textrm{g}$/kg i.v., these hypotensive action was reversed to hypertensive action in inverse proportion to the administered doses of TNPA by SCH 23390 and raclopride.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2005.05a
• /
• pp.118-118
• /
• 2005

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.3
• /
• pp.361-368
• /
• 1997

A total of 55 patients with various etiologies of infertility particitated in a study comparing two regimens of controlled ovarian hyperstimulation (COH) with GnRH agonists and gonadotropins. Nineteen patients were given an ultra-short stimulation protocol when the agonist was administered for 3 day from Day 2 of the cycle. The remaining 36 patients were given a long stimulation protocol when the agonist was administered from the mid-luteal phase of the cycle preceding the stimulation cycle. The mean number of gonadotropins used per patient was not different between two groups. No significant differences were found in the mean number of oocytes recovered, fertilization rate and embryo cleavage rate between two groups. Pregnancy and delivery rates were higher in ultra-short protocol than in long protocol, but these were not significant. These results suggest that an ultra-short protocol is as effective as a long protocol in in-vitro fertilization and embryo transfer.

• Biomolecules & Therapeutics
• /
• v.5 no.4
• /
• pp.325-330
• /
• 1997

Methanol extract of G. elata inhibited the binding of [/sup 3/H]Rol5-1788, a selective benzodiazepine receptor antagonest, to benzodiazepine receptor of rat cortices. Saturation experiments followed by Scatchard analysis of the results showed that the inhibition of [sub 3/H]Ro15-1788 binding by G. dlata. appeared to be com-petitive. These competitive inhibiton of the butanol fraction was observed to be higher than the methanol extract. Methanol extract of G. efara inhibited a [sub 3/H]flunitrazepam, a selective benzodiazepine receptor agonist, binding to benzodiazepine receptor. GABA significantly enhanced the inhibition of [/sub 3/H]flunitrazepam binding by G. elata, and these "positive GABA shift" supported the strong possibility of agonestic activity to benzodiazepine receptor Butanol fraction was observed to be higher than crude extract by methanol in an agonistic activity to benzodiazepine receptor, furthermore enhanced the binding of [sub 3/H]SR95531 to GABA receptor. Butanol fraction of G. elata significantly diminished the pentylenetetrazole-induced lethality of mice. From these results, it can be concluded that substance or substances with neurochemical properties characteri- stic of a benzodiazepine receptor agonist may be important components, and contribute to the anticonvulsant property of G. elata.

• International Journal of Oral Biology
• /
• v.34 no.4
• /
• pp.215-222
• /
• 2009

Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)-$\alpha$-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the $IP_3$ receptor antagonist 2-APB, and following the depletion of the intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular $Ca^{2+}$ store via the PLC-$IP_3$ pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.

• Toxicological Research
• /
• v.20 no.3
• /
• pp.205-211
• /
• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.9
• /
• pp.1470-1477
• /
• 2019

${\beta}_2$-adrenergic receptor (${\beta}_2-AR$) was expressed efficiently using Bac-to-Bac Baculovirus Expression System in Sf9 cells as a bio-recognition element for multianalyte screening of ${\beta}$-agonist residues in pork. Sf9 cells were selected as the expression system, and codon optimization of wild-type nucleic acid sequence and time-dependent screening of expression conditions were then carried out for enhancing expression level and biological activity. Under optimum conditions of multiplicity of infection (MOI) = 5 and 48 h post transfection, the protein yield was up to 1.23 mg/ml. After purification by chromatographic techniques, the purified recombinant protein was applied to develop a direct competitive enzyme-linked receptor assay (ELRA) and the efficiency and reliability of the assay was determined. The IC50 values of clenbuterol, salbutamol, and ractopamine were 28.36, 50.70, and $59.57{\mu}g/l$, and clenbuterol showed 47.61% and 55.94% cross-reactivities with ractopamine and salbutamol, respectively. The limit of detection (LOD) was $3.2{\mu}g/l$ and the relevant recoveries in pork samples were in the range of 73.0-91.2%, 69.4-84.6%, and 63.7-80.2%, respectively. The results showed that it had better performance compared with other present nonradioactive receptorbased assays, indicating that the genetically modified ${\beta}_2-AR$ would have great application potential in detection of ${\beta}$-agonist residues.

• Clinical and Experimental Reproductive Medicine
• /
• v.31 no.3
• /
• pp.191-200
• /
• 2004

Objective: To compare the clinical efficacy of double intrauterine insemination with single intrauterine insemination in GnRH antagonist combined ovarian hyperstimulation (Mild ovarian hyperstimulation) Materials and Methods: From Jan. 2001 to Jul. 2004, a retrospective clinical analysis was done of a total of 295 cycles in 170 patients who underwent ovarian hyperstimulation for ART (assisted reproductive technique). Subjects were divided into three groups; only clomiphene citrate ovarian hyperstimulation (n=55, 95cycles), GnRH antagonist combined ovarian hyperstimulation (soft ovarian hyperstimulation) (n=66 99cycles), and GnRH agonist combined ovarian hyperstimulation (short protocol) (n=49, 101cycles) Each group were randomly devided into two subgroups. One group underwent single IUI and the other group underwent double IUI. Results: GnRH antagonist group and GnRH agonist group had similar pregnancy rate. In GnRH antagonist Group, pregnancy rate was 36.1% in single IUI subgroup and was 36.6% in double IUI subgroup. These finding were not statistically significant. And Pregnancy rate was 20.8% in single IUI subgroup and was 19.3% in double IUI subgroup in single clomiphene citrate group, and 36.3% in single IUI subgroup and was 33.3% in double IUI subgroup in GnRH agonist group. These finding were not statistically significant, too. Conclusion: Pregnancy rate of GnRH antagonist was high and complication rate such as OHSS and multiple pregnancy was lower. In GnRH antagonist group, to compare with single IUI and double IUI, the result do not statistically differ. So GnRH antagonist single injection with single IUI was relatively comparable ART in infertiliry patient.

• Biomedical Science Letters
• /
• v.25 no.1
• /
• pp.60-65
• /
• 2019

Toll-like receptors (TLRs) are one of the families of pattern recognition receptors (PRR) operating in the innate immunity. TLRs have the ability to recognize relatively conserved microbial components, which are generally referred to as pathogen-associated molecular patterns (PAMPs). The activation of TLRs signaling leads to the activation of $NF-{\kappa}B$ and the expression of pro-inflammatory gene products such as cytokines and inducible nitric oxide synthase (iNOS). To evaluate the therapeutic potential of pristimerin, which is a naturally occurring triterpenoid compound from Celastraceae plants, iNOS expression induced by MALP-2 (TLR2 and TLR6 agonist), Poly[I:C] (TLR3 agonist), or LPS (TLR4 agonist) were examined. Pristimerin suppressed the iNOS expression induced by MALP-2, Poly[I:C], or LPS. These results suggest that pristimerin can modulate TLRs signaling pathways leading to decreased inflammatory gene expression.