• The Korean Journal of Physiology and Pharmacology
• /
• 제6권2호
• /
• pp.113-119
• /
• 2002

Long-term potentiation (LTP) at hippocampal CA3-CA1 synapses is often associated with increases in quantal size, traditionally attributed to enhanced availability or efficacy of postsynaptic glutamate receptors. However, augmented quantal size might also reflect increases in neurotransmitter concentration within the synaptic cleft since AMPA-type glutamate receptors are not generally saturated during basal transmission. Here we report evidence that peak cleft glutamate concentration $([glu]_{cleft})$ increases during LTP, as indicated by a lessening of the blocking effects of rapidly unbinding antagonists of AMPA. The efficacy of slowly equilibrating antagonists remained unchanged. The elevated $[glu]_{cleft}$ helps support the increased quantal amplitude of AMPA-type EPSCs (excitatory postsynaptic currents) during LTP.

• 약학회지
• /
• 제38권2호
• /
• pp.107-113
• /
• 1994

Ally alcohol is metabolized in the liver through two steps, first to reactive acrolein by alcohol dehydrogenase(ADH), subsequently to acrylic acid by aldehyde dehydrogenase(ALDH). Since ethanol could compete the same enzymes to be metabolized in the liver, we have studied the interaction between allyl alcohol and ethanol on liver toxicity. Simultaneous treatment of 2 g/kg ethanol by ip administration with 40 mg/kg allyl alcohol to rats increased the lethality significantly, accompanied by potentiation of the loss of hepatic glutathione. Collectively, these findings suggested that ethanol potentiated the hepatotoxicity and lethality induced by allyl alcohol probably through competing two metabolizing enzymes, ADH and ALDH.

• Archives of Pharmacal Research
• /
• 제28권1호
• /
• pp.87-92
• /
• 2005

The cyclin-dependent kinase inhibitor$p27^{kip1}$(p27) has been implicated in the regulation of cell cycle and apoptosis. Recently, we have demonstrated that ceramide induces apoptotic cell death associated with increase in the level of p27 in HL-60 cells. In the present study, we showed that overexpression of p27 increases ceramide-induced apoptotic cell death in HL-60 cells. Furthermore, overexpression of p27 accelerated DNA fragmentation, PARP cleavage and cytochrome c release induced by ceramide. In addition, ceramide induced Sax expression independent of p27. These findings indicate that enhanced effect on apoptosis by p27 is associated with mitochondrial signaling which involves cytochrome c release.

• Molecules and Cells
• /
• 제28권6호
• /
• pp.501-507
• /
• 2009

Fragile X syndrome (FXS) is caused by a lack of the fragile X mental retardation protein (FMRP) due to silencing of the Fmr1 gene. As an RNA binding protein, FMRP is thought to contribute to synaptic plasticity by regulating plasticity-related protein synthesis and other signaling pathways. Previous studies have mostly focused on the roles of FMRP within the hippocampus - a key structure for spatial memory. However, recent studies indicate that FMRP may have a more general contribution to brain functions, including synaptic plasticity and modulation within the prefrontal cortex. In this brief review, we will focus on recent studies reported in the prefrontal cortex, including the anterior cingulate cortex (ACC). We hypothesize that alterations in ACC-related plasticity and synaptic modulation may contribute to various forms of cognitive deficits associated with FXS.

• 생약학회지
• /
• 제12권4호
• /
• pp.203-207
• /
• 1981

The acute toxicity and sedative activity of flavonoids and saponin isolated from Zizyphus seeds have been evaluated in mice. All the compounds elicited potentiation of hexobarbital-induced hypnosis, inhibition of ladder-climbing and caffeine-induced hyperactivity. Swertisin was the most potent of all flavonoids tested. The potency of saponin in these tests was found to be higher than that of swertisin. The activities in rotarod test and electroshock seizure test, on the other hand, were relatively weak or nil. From these findings it was suggested that flavonoids and saponin from Zizyphus seeds have neuroleptic activity without anticonvulsant or muscle relaxant activity accompanied by neurological deficit.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2003년도 춘계학술대회 논문집
• /
• pp.91-92
• /
• 2003

Oxidative stress induced by reactive oxygen intermediates (ROIs) has been implicated in a variety of human diseases including cancer, diabetes, rheumatoid arthritis and neurodegenerative disorders. Hydrogen peroxide ($H_2O$$_2$), a representative ROI which is produced during the cellular redox process, can cause cell death via apoptosis and/or necrosis depending on its concentrations. (omitted)

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1995년도 제3회 추계심포지움
• /
• pp.125-132
• /
• 1995

In neurons, nitric oxide(NO) is produced by neuronal nitric oxide synthase following stimulation of N-methyl-D-aspartate(NMDA) receptors and the subsequent influx of Ca$\^$2+/. NO, induced in this manner, reportedly plays critical roles in neuronal plasticity, including neurite outgrowth, synaptic transmission, and long-term potentiation(LTP) (1-7). However, excessive activation of NMDA receptors has also been shown to be associated with various neurological disorders, including focal ischemia, epilepsy, trauma, neuropathic pain and chronic neurodegenerative maladies, such as Parkinson's disease, Hungtington's disease and amyotrophic lateral sclerosis(8). The paradox that nitric oxide(NO) has both neuroprotective and neurodestructive effects may be explained, at least in part, by the finding that NO effects on neurons are dependent on the redox state. This claim may be supported by the recent finding that tissue concentrations of cysteine approach 700 ${\mu}$M in settings of cerebral ischemia (9), levels of thiol that is expected to influence both the redox state of the system and the NO group itself(10).

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 1998년도 제4차 학술발표대회 및 정기총회
• /
• pp.43-44
• /
• 1998

Effect of somatic cell coculture on hatching of mouse blastocyst was examined. Mid-blastocysts were cocultured with granulosa cell primary culture or Sertoli cell line ($TM_{4}$) derived from mouse testis for 48 hr. Blastocysts cultured in medium (10% FBS) started to hatch more faster than cocultured embryos during 12 hr of coculture. After then blastocysts cocultured with somatic cell hatched faster than control. Degeneration of embryos was also greately reduced by coculture. This result suggested the potentiation of hatching as well as embryonic viability by coculture with somatic cell and Sertoli cell line can be used for embryo coculture.

• Biomolecules & Therapeutics
• /
• 제12권3호
• /
• pp.185-188
• /
• 2004

The purpose of this study is to evaluate the effect of cigarette smoke condensate (CSC) on toxification/detoxification metabolic pathway in primary cultured rat hepatocytes. We measured the activities of cytochrome P450 monooxygenases (CYP450s) and UDP-glucuronyltransferase, sulfotransferase and glutathione-S-transferase in CSC-treated rat hepatocytes. CSC significantly increased the activities of hepatic CYP4501A1 and CYP4501A2 to 7.5 fold and 1.6 fold respectively, compared with control level. However, CSC did not affect the activities of conjugation enzymes. We a1so examined if treatment of CSC could change thc cytotoxicity of acetaminophen (AA) through modulation of metabolizing enzymes. In rat hepatocytes, pretreatment with CSC potentiated the cytotoxicity of AA. This result indicates that potentiation of AA toxicity by CSC pretreatment may be related to induction of CYP4501A1 and CYP4501A2.

• 생약학회지
• /
• 제18권1호
• /
• pp.14-25
• /
• 1987

The effects of the water extract of 'Banhahubagtang', the combined herbal medicine, on the low esophageal sphincter, stomach, small intestine and CNS were investigated, and the results were as follows: The hexobarbital induced sleeping time was prolonged in female mice. The convulsion induced by electric shock was suppressed and analgesic action was recognized in mice. The extract inhibited intestinal propulsion of barium sulfate in mice. The extract inhibited free acid secretion and showed remarkable suppression of gastric ulcer in rats. Relaxation induced by isoproterenol and norepinephrine in low esophageal sphincter(L.E.S.) of rabbit was potentiated by addition of the extract. In conclusion, the Banhahubagtang exhibited anticonvulsive, sedative and L.E.S. inhibitory activities. These experimental results might indicate to be coincided with the indications for neuro-esophago-stenosis, esophagitis, esophagia, gastralgia, and neurosis which are well referred to the literature of oriental medicine.