• The Korean Journal of Physiology and Pharmacology
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• v.11 no.6
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• pp.247-251
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• 2007

Changes of single unit activity of CA1 hippocampus region were investigated in anesthetized Mongolian gerbils for six days following transient ischemia. Ischemia was produced immediately before the implantation of micro-wire recording electrodes. In control animals receiving pseudo-ischemic surgery, neither spontaneous neuronal activities ($5.70{\pm}0.4Hz$) nor the number of recorded neurons per animal changed significantly for six days. Correlative firings among simultaneously recorded neurons were weak (correlation coefficient > 0.6) in the control animals. Animals subjected to ischemia exhibited a significant elevation of neural firing at post-ischemic 12 hr ($9.95{\pm}0.9Hz$) and day 1 ($8.48{\pm}0.8Hz$), but a significant depression of activity at post-ischemic day 6 ($1.84{\pm}0.3Hz$) when compared to the activities of non-ischemic control animal. Ischemia significantly (correlation coefficient > 0.6) increased correlative firings among simultaneously recorded neurons, which were prominent especially during post-ischemic days 1, 2 and 6. Although the numbers of spontaneously active neurons recorded from control group varied within normal range during the experimental period, those from ischemic group changed in post-ischemic time-dependent manner. Temporal changes of the number of cells recorded per animal between control group and ischemic group were also significantly different (p = 0.0084, t = 3.271, df = 10). Cresyl violet staining indicated significant loss of CA1 cells at post-ischemic day 7. Overall, we showed post-ischemic time-dependent, differential changes of three characteristics, including spontaneous activity, network relationship and excitability of CA1 cells, suggesting sustained neural functions. Thus, histological observation of CA1 cell death till post-ischemic day 7 may not represent actual neuronal death.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.165.1-165
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• 1996

No Abstract, See Full Text

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.3
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• pp.131-135
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• 2006

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that ${\alpha}-receptor$ mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.304-313
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• 2010

This study was undertaken to discover the effects and possible mechanisms of the effect of red ginseng extract (RGE) on spontaneous sleep. The effects of a low dose (10 mg/kg) and a high dose (200 mg/kg) of RGE were compared in rats. After recovery from a surgical operation enabling electroencephalograms recordings, rats were administered RGE orally. RGE was administered orally for 1 day or once per day for 5 days in either 10 or 200 mg/kg doses. Polygraphic signs were recorded for 12 h after oral administration of RGE. Both treatment with a large dose (200 mg/kg) of RGE for one day and treatment with either a large or a small dose for 5 days reduced the number of sleep.wake cycles. Daily treatment with RGE (either 10 or 200 mg/kg) for 5 days augmented NREM and total sleep, but reduced wakefulness. Delta wave activity recorded during non-REM (NREM) sleep and REM sleep was increased after one treatment with RGE (either 10 or 200 mg/kg). Delta wave activity during NREM was enhanced after daily treatment with RGE (either 10 or 200 mg/kg) for 5 days. Both alpha and beta subunits of the $\gamma$-aminobutyric acid $(GABA)_A$ receptor were significantly over-expressed in the hypothalamus of the RGE-treated groups. Moreover, the expression of glutamic acid decarboxylase was also increased in the hypothalamus. These results demonstrate that RGE may regulate spontaneous sleep via $GABA_A$ergic systems.

• Advances in Traditional Medicine
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• v.6 no.2
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• pp.144-156
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• 2006

The effect of aqueous and alcoholic extracts of the fruit, leaf and stem of Melia azedarach Linn. (Meliaceae) on the spontaneous movements of both the whole worm and the nerve-muscle (n.m.) preparation of Setaria (S.) cervi and on the survival of microfilariae in vitro was studied. Alcoholic extracts of fruit, leaf and stem caused inhibition of the spontaneous movements of the whole worm and the n.m. preparation of S. cervi, while only aqueous extract of fruit caused inhibition of the spontaneous movements of the whole worm and the n.m. preparation of S. cervi. The initial stimulatory effect was not observed by the aqueous and alcoholic extracts of fruit on n.m. preparation. The concentrations required to inhibit the movements of the whole worm and n.m. preparation for alcoholic extracts of fruit, leaf and stem were 250, $40\;{\mu}g/ml$; 280, $40\;{\mu}g/ml$ and 270, $25\;{\mu}g/ml$ respectively, whereas an aqueous extract of fruit caused inhibition of whole worm and n.m. preparation at $200\;{\mu}g/ml$ and $40\;{\mu}g/ml$ respectively. Alcoholic extracts of the fruit, leaf and stem and aqueous extract of the fruit of M. azedarach caused concentration related inhibition on the survival of microfilariae (m.f.) of S. cervi. The $LC_{50}$ and $LC_{90}$ as observed after 6 h were found to be 5, 15, 10, 20 ng/ml and 10, 25, 20 and 35 ng/ml, respectively. This work was conducted in view of the exploration of potential antifilarial herbal drug.

• Journal of Family Resource Management and Policy Review
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• v.1 no.2
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• pp.79-95
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• 1997

The purpose of this empirical study is to examine the effects of middle-aged married women’s attitude and activity for leisure upon their life satisfaction. The samples were composed of 388 married women between 40 years and 59 years old, selected by age and local distribution. As the major findings of this study, the most decisive factors to enhance the life satisfaction are found as follows: First, the behavioral factor among the leisure attitudes is most affective to highten the life satisfaction. Second, self-development activity, friend-making activity and home-oriented activity are the most decisive factors in the category of participation rate of leisure activities. Third, in the types of leisure activities, leisure activity with husbands is the most affecting. Also, the economic factor of the samples was the most significant factor to affect the life satisfaction. The findings of this study provide some implications regarding the policies on the leisure facilities, leisure education programs, the governmental and social supporting systems, and the spontaneous efforts of women themselves to enhance the quality of life of the middle-aged married women.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.461-467
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• 2009

The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.297-302
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• 2006

Melittin, a major component of bee venom, produces a sustained decrease in mechanical threshold, and an increase in spontaneous flinchings and paw thickness, which are characteristics similar to those induced by whole bee venom. Melittin-induced nociception has been known to be modulated by the changes in the activity of excitatory amino acid receptors, voltage-dependent calcium channels, cyclooxygenase and serotonin receptors. The present study was undertaken to investigate the role of calcium chelators (TMB-8 & Quin 2) in melittin-induced nociceptive responses. Changes of mechanical threshold and spontaneous flinching behaviors were measured at a given time point following intraplantar injection of melittin ($30{\mu}g/paw$). Intrathecal or intraplantar pre-administration and intrathecal posttreatment of TMB-8 and Quin 2 significantly prevented the melittin-induced reduction of mechanical threshold, and intraplantar or intrathecal pre-treatment of TMB-8 and Quin 2 suppressed melittininduced flinching behaviors. These results indicate that calcium ion in the spinal dorsal horn neurons and peripheral nerves plays an important role in the production and maintenance of mechanical allodynia and spontaneous pain by melittin.

• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.329-332
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• 2002

We have investigated the role of slow inhibitory neurons in spontaneous activity using a model network controlled by stochastic mean field theory based on Integrated-and-Fire excitatory and fast inhibitory neurons. It is found that inputting slow inhibitory neurons to such network induces stable spontaneous activity at a much lower threshold than without slow inhibitory neurons in the network. This threshold range is low enough to be considered as biological threshold of cortical neurons. Only slow inhibitory neurons can give adjustable negative feedback in the network keeping lower rate and lower threshold.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.4
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• pp.603-607
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• 2011

The purpose of this study is to investigate the effects of Carthami Flos on interstitial cells of Cajal in the gastrointestinal tract. Many regions of the tunica muscularis of the gastrointestinal (GI) tract display spontaneous contraction. These spontaneous contractions are mediated by periodic generation of electrical slow waves. Recent studies have shown that the interstitial cells of Cajal (ICCs) act as pacemakers and conductors of electrical slow waves in gastrointestinal smooth muscles. We investigated the cytotoxicity activity, antioxidant activity, and pacemaking activity. The cytotoxicity activity was measured by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Antioxidant activities were determined by DPPH (1.1-diphenyl-2-picrylhydrazyl) radical scavenging capacity assay and DCFH-DA (2,7-dichlorofluorescein diacetate) method. The effects of Carthami Flos on the pacemaker potentials in cultured ICCs from murine small intestine were investigated by using whole-cell patch-clamp techniques at $30^{\circ}C$. The addition of Carthami Flos (5, 10, $30{\mu}g$/ml) depolarized the resting membrane potentials in a concentration dependent manner. These results suggest that the GI tract can be targets for Carthami Flos, and their interaction can affect intestinal motility.