• Title/Summary/Keyword: rate dependent

Search Result 3,171, Processing Time 0.032 seconds

Antidepressant drug paroxetine blocks the open pore of Kv3.1 potassium channel

  • Lee, Hyang Mi;Chai, Ok Hee;Hahn, Sang June;Choi, Bok Hee
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.22 no.1
    • /
    • pp.71-80
    • /
    • 2018
  • In patients with epilepsy, depression is a common comorbidity but difficult to be treated because many antidepressants cause pro-convulsive effects. Thus, it is important to identify the risk of seizures associated with antidepressants. To determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to high-frequency firing of interneurons, using the whole-cell patch-clamp technique. Kv3.1 channels were cloned from rat neurons and expressed in Chinese hamster ovary cells. Paroxetine reversibly reduced the amplitude of Kv3.1 current, with an $IC_{50}$ value of $9.43{\mu}M$ and a Hill coefficient of 1.43, and also accelerated the decay of Kv3.1 current. The paroxetine-induced inhibition of Kv3.1 channels was voltage-dependent even when the channels were fully open. The binding ($k_{+1}$) and unbinding ($k_{-1}$) rate constants for the paroxetine effect were $4.5{\mu}M^{-1}s^{-1}$ and $35.8s^{-1}$, respectively, yielding a calculated $K_D$ value of $7.9{\mu}M$. The analyses of Kv3.1 tail current indicated that paroxetine did not affect ion selectivity and slowed its deactivation time course, resulting in a tail crossover phenomenon. Paroxetine inhibited Kv3.1 channels in a use-dependent manner. Taken together, these results suggest that paroxetine blocks the open state of Kv3.1 channels. Given the role of Kv3.1 in fast spiking of interneurons, our data imply that the blockade of Kv3.1 by paroxetine might elevate epileptic activity of neural networks by interfering with repetitive firing of inhibitory neurons.

Effects of the AngiotensinII $AT_1$ Receptor Antagonist SK-1080 on Ischemia/reperfusion in Isolated Rat Hearts and on Platelet Aggregation and Coagulation in Human Blood (Angiotensin II $AT_1$ 수용체 길항제인 SK-1080의 적출심장에 대한 허혈후 재관류시의 작용 및 혈소판응집과 혈액응고에 대한 효과)

  • Woo, Su-Kyoung;Choi, Sang-Su;Lee, Byung-Ho;Kwon, Kwang-Il
    • YAKHAK HOEJI
    • /
    • v.44 no.6
    • /
    • pp.558-565
    • /
    • 2000
  • SK-1080 is one of the newly developed orally active nonpeptide angiotensinII $AT_1-receptor$ antagonist that selectively acts at $AT_1$ receptor with high affinity. The cardiac effect on ischemia/reperfusion injury of SK-1080 was compared with those of losartan, a prototype of this class, in isolated rat hearts. Isolated perfused rat heart was pretreated with drug for 10 min and then subjected to global ischemia for 30 min followed by reperfusion with- or without drug for 30 min. The possible additive effect of SK-1080 on the platelet aggregation and coagulation in human blood was also studied. We investigated whether SK-1080 effects the platelet aggregation induced by ADP, a platelet agonist partially dependent on $thromboxaneA_2$. The clotting times in the prothrombin time (PT) and activated partial thromboplastin time (APTT) were also examined in human plasma in vitro as coagulation screening test. SK-1080 improved reperfusion function (LVDP, left ventricular developed pressure; PRP, rate-pressure product) in a dose-dependent manner. SK-1080 reduced ADP-induced platelet aggregation compared with vehicle but less than losartan, and did not affect clotting times.

  • PDF

Ginsenosides attenuate the 3-nitropropioic acid-induced rat striatal degeneration in an age-dependent manner

  • Kim, Jong-Hoon;Nah, Seung-Yeol
    • Journal of Ginseng Research
    • /
    • v.29 no.2
    • /
    • pp.100-106
    • /
    • 2005
  • The number of reporting the effects on ginseng's physiological, pharmacological, and behavioral effects has been increased every year. Major active components of Panax ginseng, are the ginsenosides, which are mainly triterpenoid dammarane derivatives. 3-Nitropropionic acid (3-NP) is blown to induce cellular energy deficit and oxidative stress related neurotoxicity via an irreversible inhibition of the mitochondrial enzyme succinate dehydrogenase (SDH). Intraperitoneal injection of 3-NP produces striatal degeneration. Aged animals was more vulnerable to 3-NP than young animal. We used three different ages of 5-, 8-, and 26-week-old rats. 3-NP alone treatment induced striatal lesion and increased lesion volume with age-dependent manner in 5-, 8-, and 26-week-old rats by $30.2{\pm}5.8$, $v$, and $51.3{\pm}8.4mm^3$, respectively. However, pretreatment of GTS (100 mg/kg/day) before 3-NP reduced striatal lesion in 5-,8-, and 26-week-old rats by $3.15{\pm}6.1$, $8.89{\pm}1.9$, and $27.3{\pm}5.6mm^3$, respectively. Pretreatment of GTS also significantly increased survival rate in 5-week-old rats (3-NP alone: GTS +3-NP = $40.4{\pm}6.3$: $72.5{\pm}9.5\%$) than 8-week-old rats (3-NP alone: GTS + 3-NP : $13.5{\pm}5.2\%$ : $45.1{\pm}3.1\%$). In 26-week-old rats, 3-NP alone treated group died on day 18, whereas GTS +3-NP-treated group prolonged lifespan to 30 days. Thus, pretreatment of GTS before administration of 3-NP extended lifespan in all ages. The present results indicate that aged animals are more vulnerable to 3-NP and GTS pretreatment protected 3-NP-induced striatal damage in different ages of animals.

The Experimental Study on Anti-thrombotic and Anti-inflammatory Effect of BokbangHongdeungPaejangSan (BHPS) (복방홍등패장산(復方紅藤敗醬散)의 항혈전(抗血栓) 및 항염작용(抗炎作用)에 대한 실험적(實驗的) 연구(硏究))

  • Lim, Dong-Ug;Yoo, Dong-Youl
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.19 no.3
    • /
    • pp.151-173
    • /
    • 2006
  • Purpose : This study was performed to evaluate anti-thrombotic and anti-inflammatory effects of BokbangHongdeungPaejangSan water extract (BHPS). Methods : BHPS was investigated using cultured cells and a murine models. As for the parameters of inflammation, levels of several inflammatory cytokines and chemical mediators which are known to be related to inflammation were determined in mouse lung fibroblast cells (mLFC) and RAW 264.7 cells. Results : In experiment of anti-thrombotic effect, BHPS inhibited the platelet aggregation induced by ADP and epinephrine, and inhibited pulmonary embolism induced by collagen and epinephrine. BHPS increased Platelet number and fibrinogen amount, and shortened PT and APTT in thrombus model induced by dextran. In experiment of anti-inflammatory effect, BHPS inhibited IL-1${\beta}$, IL-6, TNF-${\alpha}$, COX-2 and NOS-II mRNA expression in a concentration-dependent manner in RAW 264.7 cell line, and inhibited significantly NO production at 50, 100 ${\mu}g/ml$, and also inhibited ROS production in a concentration-dependent manner. BHPS inhibited IL-1${\beta}$, IL-6 and TNF-${\alpha}$ production significantly in serum of acute inflammation-induced Balb/c mice, and decreased IL-1${\beta}$, IL-6 and TNF-${\alpha}$ production in spleen tissue, but increased IL-1${\beta}$, IL-6 and TNF-${\alpha}$ production in liver tissue. BHPS increased survival rate at the 3th day in ICR mice with lethal endotoxemia induced by LPS. Conclusion : These results suggest that BHPS can be used for treating diverse female diseases caused by thrombosis and inflammation such as endometriosis, pelvic pain, cervicitis, pelvic inflammatory disease and pelvic tuberculosis and so forth.

  • PDF

Postoperative Survival and Ambulatory Outcome in Metastatic Spinal Tumors : Prognostic Factor Analysis

  • Moon, Kyung-Yun;Chung, Chun-Kee;Jahng, Tae-Ahn;Kim, Hyun-Jib;Kim, Chi-Heon
    • Journal of Korean Neurosurgical Society
    • /
    • v.50 no.3
    • /
    • pp.216-223
    • /
    • 2011
  • Objective : The purposes of this study are to estimate postoperative survival and ambulatory outcome and to identify prognostic factors thereafter of metastatic spinal tumors in a single institute. Methods : We reviewed the medical records of 182 patients who underwent surgery for a metastatic spinal tumor from January 1987 to January 2009 retrospectively. Twelve potential prognostic factors (age, gender, primary tumor, extent and location of spinal metastases, interval between primary tumor diagnosis and metastatic spinal cord compression, preoperative treatment, surgical approach and extent, preoperative Eastern Cooperative Oncology Group (ECOG) performance status, Nurick score, Tokuhashi and Tomita score) were investigated. Results : The median survival of the entire patients was 8 months. Of the 182 patients, 80 (44%) died within 6 months after surgery, 113 (62%) died within 1 year after surgery, 138 (76%) died within 2 years after surgery. Postoperatively 47 (26%) patients had improvement in ambulatory function, 126 (69%) had no change, and 9 (5%) had deterioration. On multivariate analysis, better ambulatory outcome was associated with being ambulatory before surgery (p=0.026) and lower preoperative ECOG score (p=0.016). Survival rate was affected by preoperative ECOG performance status (p<0.001) and Tomita score (p<0.001). Conclusion : Survival after metastatic spinal tumor surgery was dependent on preoperative ECOG performance status and Tomita score. The ambulatory functional outcomes after surgery were dependent on preoperative ambulatory status and preoperative ECOG performance status. Thus, prompt decompressive surgery may be warranted to improve patient's survival and gait, before general condition and ambulatory function of patient become worse.

A Review for Non-linear Models Describing Temperature-dependent Development of Insect Populations: Characteristics and Developmental Process of Models (비선형 곤충 온도발육모형의 특성과 발전과정에 대한 고찰)

  • Kim, Dong-Soon;Ahn, Jeong Joon;Lee, Joon-Ho
    • Korean journal of applied entomology
    • /
    • v.56 no.1
    • /
    • pp.1-18
    • /
    • 2017
  • Temperature-dependent development model is an essential component for forecasting models of insect pests as well as for insect population models. This study reviewed the nonlinear models which explain the relationship between temperature and development rate of insects. In the present study, the types of models were classified largely into empirical and biophysical model, and the groups were subdivided into subgroups according to the similarity of mathematical equations or the connection with original idea. Empirical models that apply analytical functions describing the suitable shape of development curve were subdivided into multiple subgroups as Stinner-based types, Logan-based types, performance models and Beta distribution types. Biophysical models based on enzyme kinetic reaction were grouped as monophyletic group leading to Eyring-model, SM-model, SS-mode, and SSI-model. Finally, we described the historical development and characteristics of non-linear development models and discussed the availability of models.

Analysis of Researches on the Warming Therapy for Surgical Patients (수술 환자에게 적용한 가온요법 연구논문 분석)

  • Jun, Jum-Yi
    • Korean Journal of Adult Nursing
    • /
    • v.22 no.3
    • /
    • pp.260-270
    • /
    • 2010
  • Purpose: The main question is systematic review of the published in Korea and foreign countries on warming therapy for surgical patients. Methods: The researchers searched at Medline, CINAHL, KERIS, Adult Nursing Association, Korean Society of Nursing Science, Korean Academy of fundamentals of Nursing, and National Assembly Library web site for the published on warming therapy for surgical patients from 1980 to 2008. Words for search were operation/surgery, warming, operation/surgery and warming. Studies were included randomized controlled trial, and there were no restrictions regarding operative phase and outcome measures. Results: 36 published researches that met the criteria were mostly published in foreign countries between 2000 and 2008 and focused on surgery with general anesthesia. Sample size ranged from 21 to 60 subjects, age range between 21 and 60 years of age. Thirty different warming therapies were reported, fifty-two different dependent variables. Outcome indicators included active external warming, intra-operative, and body temperature. 'Positive effects' and 'no effects' equaled. The most frequently reported 'positive effects' were body temperature, shivering, and acid-base balance. No effects were more likely to be heart rate, blood pressure, and hemodynamics. Conclusion: Many types of warming therapy, are reported in the literature with little information about the efficacy of each, many different dependant variables were studied. There were no consistent reports as to length of time used for warming procedures. Overall, the effects of warming therapy are inconsistent. And additional research must be down before any particular method of warming can be used with confidence as to its effectiveness. Attention must be made as to the research design, better measurement of the dependent variables. This review may serve as a base.

Age-Related Changes of Adult Neural Stem Cells in the MouseHippocampal Dentate Gyrus

  • Jung, Ji-Yeon;Byun, Kang-Ok;Jeong, Yeon-Jin;Kim, Won-Jae
    • International Journal of Oral Biology
    • /
    • v.33 no.2
    • /
    • pp.59-64
    • /
    • 2008
  • This study was designed to investigate the changes in the properties of the neuronal setm cells or progenitor cells associated with age-related decline in neurogenesis of the hippocampal dentate gyrus (DG). Active whole cells cycle marker Ki67 (a marker of whole cell cycle)-positive and S phase marker bromodeoxyuridine (BrdU)-positive. Neural stem cells gradually were reduced in the hippocampal subgranular zone (SGZ) in an age-dependant manner after birth (from P1 month to P1 year). The ratio of BrdUpositivecells/Ki67-positive cells was gradually enhanced in an age-dependent manner. The ratio of Ki67-positive cells/accu-mulating BrdU-positive cells at 3 hrs after BrdU injection was injected once a day for consecutive 5 days gradually decreased during ageing. TUNEL- and caspase 3 (apoptotic terminal caspase)-positive cells gradually decreased in the dentate SGZ during ageing and immunohistochemical findings of glial fibrillary acid protein (GFAP) were not changed during ageing. NeuN, a marker of mature neural cells, and BrdU-double positive cells gradually decreased in an age-dependent manner but differentiating ratio and survival rate of cells were not changed at 4 wks after BrdU injection once a day for consecutive 5 days. The number of BrdU-positive cells migrated from the hippocampal SGZ into granular layer and its migration speed was gradually declined during ageing. These results suggest that the adult neurogenesis in the mouse hippocampal DG gradually decrease through reducing proliferation of neural stem cells accompanying with cells cycle change and reduced cells migration rather than changes of differentiation.

Affinity Labeling of E. coli GTP Cyclohydrolase I by a Dialdehyde Derivative of Guanosine Triphosphate

  • Ahn, Chi-Young;Park, Sang-Ick;Kim, Ju-Myeong;Yim, Jeong-Bin
    • BMB Reports
    • /
    • v.28 no.1
    • /
    • pp.72-78
    • /
    • 1995
  • Time-dependent inactivation of E. coli GTP cyclohydrolase I with a 2',3'-dialdehyde derivative of GTP (oGTP) was directed to the active site of the enzyme, and was dependent on the concentration of oGTP. The kinetics of inactivation were biphasic with a rapid reaction occurring immediately upon exposure of the enzyme to oGTP followed by a slow rate of inactivation. The $K_i$ value of oGTP for the enzyme was 0.25 mM. Inactivation was prevented by preincubation of the enzyme with GTP, the substrate of the enzyme. At 100% inactivation, 2.3 mol of [8.5'-$^3H$]oGTP were bound per each enzyme subunit, which consists of two identical polypeptides. The active site residue which reacted with the affinity label was lysine. oGTP interacted selectively with the ${\varepsilon}$-amino group of lysine in the GTP-binding site to form a morpholine-like structure which was stable without sodium borohydride treatment. However, triphosphate group was eliminated during the hydrolysis step. To identify the active site of the enzyme, [8.5'-$^3H$]oGTP-labeled enzyme was cleaved by endoproteinase Lys-C, and the $^3H$-labeled peptide was purified by HPLC. The amino acid sequence of the active site peptide was Pro-Ser-Leu-Ser-Lys, which corresponds to the aminoterminal sequence of the enzyme.

  • PDF

Ginsenoside-Rh2 Inhibits Proliferation and Induces Apoptosis of Human Gastric Cancer SGC-7901 Side Population Cells

  • Qian, Jun;Li, Jing;Jia, Jian-Guang;Jin, Xin;Yu, Da-Jun;Guo, Chen-Xu;Xie, Bo;Qian, Li-Yu
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.17 no.4
    • /
    • pp.1817-1821
    • /
    • 2016
  • Objectives: To observed the effects of ginsenoside -Rh2 (GS-Rh2) on proliferation and apoptosis of side population (SP) human gastric cancer SGC-7901 cells. Materials and Methods: SGC-7901 SP and Non-SP cells were sorted by flow cytometry and assessed using the cck-8 method. Expression of apoptosis-related proteins Bax and Bcl-2 of SP before and after the intervention was determined by Western-blotting. Results: It was found that the proliferation of SP was significantly faster than that of NSP (P<0.05). In addition, GS-Rh2 inhibited proliferation of gastric cancer SP cells, induced cell cycle arrest and cell apoptosis, and changed the expression of BAX/Bcl-2 proteins in a time-dependent and concentration-dependent manner (P<0.05). Conclusions: With increase of GS-Rh2 dose, GS-Rh2 gradually inhibit the proliferation of SGC-7901 SP cells, which have high proliferation rate, through G1/G0 phase arrest, followed by apoptosis which involves the up-regulation of Bax and the down-regulation of Bcl-2.