• The Korean Journal of Physiology
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• v.20 no.1
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• pp.1-7
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• 1986

It has been well documented that the peripheral autonomic nervous system plays an important role in exocrine pancreatic secretion. However, the role of the central nervous system in pancreatic function is still obscure even though the central nervous system has been known to control gastrointestinal functions through the autonomic nervous system. Since the reticular formation in the mesencephalone seems to integrate the autonomic function, the present study was undertaken to investigate a possible influence of the reticular formation upon the exocrine pancreatic secretion. Twenty·two albino rats fasted for 24 hours were anesthetized by intraperitoneal injection of urethane in a dose of 1 g/kg, The pancreatic duct was cannulated to collect pancreatic juice and bile juice was diverted to the jejunum. The gastroduodenal junction was ligated to Prevent passage of gastic juice into the duodenum. A pair of electrodes were bilaterally inserted in the reticualr formation of the mesencephalone with aid of a stereotaxic apparatus. When the volume of pancreatic juice secreted for 10 min became constant, the reticular formation was electrically stimulated for 10 min. Parameters of the electical stimulation was 1.3V, 40 Hz and 2 msec. When the pancreatic secretion returned to the level before the electrical stimulation, cervical vagotomy (11 rats) or administration of propranolol (11 rats) in a dose of 0.1 mg/kg through the jugular vein was carried out. Ten minutes after the treatment, the electrical stimulation of the reticular formation was repeated. The brain was fixed by perfusion of 10% formaline solution through the heart, and then placement of the electrode tip was examined histologically. Protein concentration and amylase activity in samples of Pancreatic secretion were measured. The electrical stimulation of the reticular formation significantly increased in volume $({\mu}l/10\;min)$, Protein output $({\mu}g/10\;min)$ and amylase output (U/10 min) in the pancreatic secretion. The stimulatroy effects were not affected by the cervical vagotomy but completely abolished by propranolol. Meantime, it was also observed that both vagotomy and propranolol significantly reduced the pancreatic secretory function. These results indicate that the reticular formation in the mesencephalone may exert a stimulatory effect upon the Pancreatic secretory function not through the vagus nerve but through the sympathetic pathway in anesthetized rats.

• The Korean Journal of Physiology
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• v.22 no.1
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• pp.63-77
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• 1988

This study was carried out to investigate relationships between maximal running time (MRT) and glycogen supercompensation in fast twitch white fibers (white vastus, WV), fast twitch red fibers (red vastus, RV) and slow twitch red fibers (soleus muscle, SM) of endurance-trained rats. Male rats of a Sprague-Dawley strain were divided into the trained groups and untrained groups. Untrained groups were acquired to run on the treadmill 10 minutes for 3 days and remained rest and maintained with mixed diet for 4 weeks. For last 10 days of resting period, the untrained rats were divided into 3 groups i.e. mixed diet (untrained control), high and low carbohydrate (CHO) diet groups. And each group was subdivided into 2 groups, one group was tested for the MRT and the other was sacrificed to measure the blood glucose, blood lactate, glycogen contents of liver and muscles. The experimental groups were trained on treadmill by a modified method of Constable et al. (1984) maintained with mixed diet for 4 weeks. After measurement of MRT of this group, they were also divided into high and low CHO groups and fed with these diet for 2 days and MRT of each group was measured again to see the effect of high or low CHO feeding on the MRT. Each group was maintained with the same diet for next 2 days during which some of the rats were sacrificed at given time intervals for the measurements of blood glucose and lactate, liver and the muscles glycogen. The results were summarized as follows; 1) In the untrained group, there were no significant differences between subgroups in MRT, glycogen conent of SM, RV and WV. But blood glucose concentration and glycogen content of liver of low CHO group were significantly lower than those of mixed diet group. 2) The MRT and glycogen content of SM, RV and WV of trained mixed diet group were significantly increased compared to those of untrained mixed diet group, but there was no significant difference in glycogen content of liver. 3) MRT of trained mixed, high CHO and low CHO groups were $137{\pm}9.8,\;176{\pm}9.8\;and\;129{\pm}7.3\;min$ respectively with the significant difference between them. 4) There were no differences in blood lactate concentrations between the trained high and low CHO groups immediately after maximal running and during recovery period. 5) Glycogen contents in RV and SM of trained high CHO group were significantly increased, and glycogen contents in RV, WV and liver of trained low CHO group were significantly decreased compared to those of trained mixed diet group. 6) Immediately after maximal running, the blood glucose concentrations of trained high CHO and low CHO groups were $73{\pm}4.0\;and\;67{\pm}6.9mg%$ respecitively. The blood glucose of the trained high CHO group was fully recovered within one hour by feeding. But blood glucose concentration of low CHO group was slowly recovered up to $114{\pm}4.1mg%$ after two hours of feeding and maintained. Those values were still significantly lower than that of trained mixed diet group. The synthetic rates of glycogen in liver and muscles during the recovery period followed the similar time course of the blood glucose recoveries in each group. These results suggest that an increase in MRT of trained high CHO group was attributed to the glycogen supercompensation in slow twitch muscle fibers. And a decrease in MRT of trained low CHO may be due to decreased glycogen contents of liver and muscles. The results also suggest that glycogen supercompensation was more evident in slow twitch red fibers of endurance-trained rats and blood glucose is one of the limiting factors of glycogen synthesis.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.9-16
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• 1973

In view of the recent knowledge on the radioprotective action of reduced glutathione (GSH), the present study was designed the elucidate the effect of some concentrations of GSH on the levels of intrinsic non-protein sulfhydryl (NP-SH) and non-protein disulfide (NP-SS) of the mouse liver incubated at 4, 25 and 37C in vitro, respectively. The liver slice of the mouse was incubated at 4, 25 and 37C in the medium composed of 100 ml of Krebs-Ringer phosphate buffer (KRP) with the addition of 10, 20 and 30 mg of GSH, respectively. Measurement of NP-SH and NP-SS was made at 5, 30 and 60 min during the course of the incubation, and the results were compared with the controls which were incubated only in KRP medium, and the normal. The results thus obtained are summarized as follows: 1. When the mouse liver slice was incubated at 4C, the values of both NP-SH and NP-SS of the control and the group where 10 mg of GSH was added to the incubation medium were similar to those of the normal group, and the increase of NP-SH and NP-SS with the increased concentrations of GSH was not prominent. 2. When the liver slice was incubated in the concentrations of GSH 20 mg/100 ml KRP and GSH 30 mg/100 ml KRP at 25 C, the rate of increase of both NP-SH and NP-SS was proportional to the increase of GSH concentration. In the group where 10 mg of GSH was added to the incubation medium, the value of NP-SH and NP-SS reached the highest value at 30 min, but a tendency of decrease was observed at 60 min. 3. The rate of increase of NP-SH and NP-SS of the liver was most marked of all the group. studied when the incubation temperatuse was elevated to 37C, and the increase was proportional to the concentration of GSH and the incubation time.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.1-8
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• 1973

Though it has been reported by Clements et al. and Avery et al. that the activity of the pulmonary surfactant can be altered by the temperature changes, a conclusive evidence of the effects of temperature on the surfactant system of the lung is yet to come. In the present study, an attempt was made to observe possible effects of a few different degrees of temperature on the activity of the pulmonary surfactant of the rabbit in vivo and in vitro. The rabbit was sacrificed by blood shedding and both lungs were completely removed. The lung washings, obtained by gently lavaging the left lung with saline, was placed at 1) 4C for 1, 5, 10, 15, 30 and 40 days, and 2) 20C for 1, 2, 3, 4, 5 and 7 days for in vitro experiment. For in vivo experiment, the rabbit was placed at 4C for 4, 8, 12 and 24 hours, and the lung lavage was prepared as described above in the in vitro experiment. Tension-area (T-A) diagram of the lung lavage was recorded automatically by a modified. Langmuir-Wilhelmy balance with a synchronized recording system. The surface tensions thus obtained were compared with those of the normal rabbit, and the results are summarized as follows: 1. The maximal surface tension, minimal surface tension and stability index of the normal rabbit lung lavage were $52.5{\pm}2.3\;dynes/cm,\;4.9{\pm}2.3\;dynes/cm$ and 1.65, respectively. 2. In the group where the lung lavage was placed at 4C in vitro, the maximal and minimal surface tensions, and stability index did not show any noticeable changes comparing with the normal values up to 30 days. On the 40th day of the experiment, a tendency of a slight increase in the surface tensions was observed but the change was not significant. 3. When the lung lavage was placed at 20 C in vitro, the maximal surface tension did not show any appreciable change comparing with the normal except on the 7 th day with a slight increase. The minimal surface tension showed an increased value from the 2nd day, and on the 5 th and 7 th experimental day, markedly increased value was observed. The stability index, on the other hand. showed a marked decrease throughout the entire experiment with the value of 0.71 and 0.53 on the 5th and 7 th day, respectively. 4. In the group where the rabbit was placed at 4 C in vivo, the maximal surface tensions and stability index of the lung lavage showed little change from the normal. The minimal surface tension at 12 experimental hour showed a slight increase, but it returned to the normal value at 24 hour.

• The Korean Journal of Physiology
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• v.20 no.1
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• pp.17-29
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• 1986

The present study was carried out to observe the effect of triiodothyronine on heart, one of the target organ of thyroid hormone. There are many reports that tachycardia, arrythmia, and agumentation of sodium, potassium pump activity are caused in hyperthyroid animal. To examine these cardiac positive chronotropic effects on sinoatrial (SA) node and atrial muscle, hyperthyroid state was induced experimentally by the injecion of 3,3',5-1-triiodothyronine $(T_3)$ in $3{\sim}6$ month-old rabbits. Then intracellular recordings by inserting glass microelectrode into cell were obtained in SA node and atrial muscle. The results can be summarized as follows : 1) Heartbeat was increased from $169.6{\pm}28.0\;to\;264.2{\pm}18.0$ beats per minute, while body weight was decreased to 68f of the initial body weight (Day 1). 2) In experimental group, the duration of action potential at 80% repolarization was decreased from $148.0{\pm}29.1\;to\;107{\pm}13.6msec$. This suggested the increase heartbeat. 3) The firing rate in hyperthyroid group markedly reduced under the 15 mM potassium Tyrode (p<0.005). 4) In hyperthyroid group, depolarization of atrial muscle cell was lowered significantly in 15 mM (p<0.05), 20 mM (p<0.05) potassium Tyrode solution. 5) Sodium-potassium pump activities in experimental group were higher than those in control group in both SA node (p<0. 1) and atrial muscle (p<0.025). 6) In lower concentration of $MnCl_2$, the excitability of SA node in hyperthyroid group was decreased more than that in control group. Effective inhibitory dose $(ID_{50})$ as 0.6 mM in hyperthyroid statd and 1.1 mM in control group.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.49-58
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• 1973

The distensibility of the major arteries has been investigated extensively, but the value expressed as Young Modulus varies widely by the different schools of the investigators, the major reason undoubtedly being the difficulties encountered in the measurement. In the present study, an attempt was made to elucidate the distensibility of the external carotid artery of the rabbit, which was placed in saline immediately after removing from the apparently healthy, normal rabbit without anesthesia. The circular section strip and longitudinal section strip were made from the whole artery, and Young Modulus of the whole artery, circular section and longitudinal section strips was calculated from the length-tension curve of each sample. Also, the similar samples of the artery seperately obtained were placed in ATP solution in the concentration of 0.15 mM and 0.30 mM, and Young Modulus was similary calculated. Experiments were performed at 15,45 and 75 min after the artery was removed from the rabbit, and the results thus obtained are summarized as follows. 1) Young Modulus of the whole external carotid artery of the rabbit in saline was $4.74{\times}10^7dyne/cm^2$ at 15 min, but lower values were obtained at 45 and 75 min, Young Modulus being $4.62{\times}10^7dyne/cm^2\;and\;4.13{\times}10^7dyne/cm^2$, respectively. When the arterial samples were placed in ATP solutions, Young Modulus did not change much throughout the experiment, and lower Young Moduli were obtained in 0.30 mM ATP solution than in 0. 15 mM ATP solution. 2) Young Modulus Of the Circular Section Strip in Saline was $4.11{\times}10^7dyne/Cm^2,\;3.75{\times}10^7dyne/cm^2\;and\;3.90{\times}10^7dyne/cm^2,$ respectively, at 15, 45 and 75 min, the value at 15 min being the highest. However, when the strip was placed in ATP solutions, no appreciable change was observed throughout the experiment, and Young Moduli were lower in 0.30 mM ATP solution than in 0.15 mM ATP solution. 3) Young Modulus of the longitudinal section strip in saline was $2.12{\times}10^7dyne/cm^2,\;2.48{\times}10^7dyne/cm^2\;and\;2.46{\times}10^7dyne/cm^2$, respectively, at 15, 45 and 75 min, Young Modulus being slightly elevated in the latter part of the experiment. A similar tendency was observed when the strip was placed in ATP solutions.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.275-280
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• 2011

BACKGROUND: The present study was conducted to find out the suitable method for organic rice production on the basis of different seedling raising methods at nine eco-friendly agricultural units of Samgi, Mangsung, Iksan and Sungsan, Gusan of Jeollabuk-do, during 2009-10. METHODS AND RESULTS: On the basis of yield and physiological parameters, pot seeding method was found to be superior to drill seeding and broadcast seeding methods. The number of panicle, grain, the precent of ripened grains, and the 1,000 grain weight, were better in pot seeding method. Maximum yield and other attributes were recorded in rice, cultivated with seedlings raised by pot and broadcast seeding method. Number of panicle/hill and grain/panicle was 10.4% and 35.1% higher than the broadcast seeding method, respectively. Yield also showed 8.8% increase in pot seeding method as compare to broadcast seeding method. Higher grain yield was obtained when 56 hills/$3.3m^2$ of rice seedlings were used as compare to 50 hills/$3.3m^2$ raised by pot seeding method and 70 hills/$3.3m^2$ of broadcast seeding method. Lodging was minimum in seedlings raised with pot seeding method as thickness of third internode was more (9.0%) than the seedlings, raised with broadcast seeding method. Root length and dry weight also showed similar tendency i.e. 13.8% and 25.3% higher, respectively. CONCLUSION(s): Quality and grade of rice, cultivated with pot seeding method was better than broadcast seeding method. Head rice was 4.4% higher; and protein content and broken rice grown by pot seeding method were 0.4% and 1.8% lower than broadcast seeding method, respectively.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.344-350
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• 2006

An Antiviral producing bacterial strain was isolated from ginseng root environment in Hongcheon, Kangwon province of Republic of Korea. Identification of this bacterial strain was performed by physiological and biochemical tests along with 16S rRNA analyses. The results revealed that the bacterium was closer to genus Serratia, which was named as Gsm01. The strain was grown in Mannitol-Glutamate-Yeast (MGY) broth for 48 h. The culture was centrifuged and the filtrate obtained was tested for its ability to control Cucumber mosaic virus strain Y (CMV-Y) in greenhouse and field experiments. In the green house experiments, CF was evaluated for its ability to protect local host, Chenopodium amaranticolor and systemic host of CMV, Nicotiana tabacum cv. Xanthi-nc. It was found that, CF treatment reduced viral infection by 98% in local host; C. amaranticolor. The N. tabacum cv. Xanthi-nc plants treated with CF did not show visible viral symptoms 15 days post inoculation (dpi) and remained symptomless throughout the periods of the study. To evaluate effectiveness of CF under field conditions, experiment was carried out in a polyvinyl house. It was observed that, 52% plants were protected from viral diseases compared to non-treated plants, increasing the crop yield. This is the first report showing antiviral activity of a Serratia spp. against CMV.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.51-59
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• 2017

This study evaluated the drought tolerance of Liriope platyphylla F.T.Wang & T.Tang, Dendranthema zawadskii var. lucidum (Nakai) J.H.Park, Hosta longipes (Franch. & Sav.) Matsum., Sedum sarmentosum Bunge and Zoysia japonica Steud. for an extensive green roof. In order to assess drought tolerance of green roof plants, several criteria were measured such as volumetric water content, leaf and soil moisture potential, chlorophyll a and b, chlorophyll fluorescence, photosynthesis, stomatal conductance, transpiration rate and antioxidants. The results of the drought tolerance measurement of green roof plants focused on the gradually withering of plants from lack of volumetric water content. D. zawadskii was the first to show an initial wilting point, followed by Z. japonica, H. longipes and L. platyphylla in order while S. sarmentosum showed no withering. It was concluded that H. longipes, L. platyphylla and S. sarmentosum were highly drought tolerant plants able to survive over three weeks. Furthermore, chlorophyll a and b were divided into two types: Type I, which kept regular content from the beginning to the middle of the period and suddenly declined, like H. longipes and Z. japonica; and Type II, which showed low content at the beginning, sharply increased at the middle stage and decreased, like D. zawadskii, L. platyphylla and S. sarmentosum. Volumetric water content and the amount of evapotranspiration consistently declined in all plant species. The analysis of chlorophyll fluorescence results that S. sarmentosum, which had relatively high drought tolerance, was the last to decline, while Z. japonica and S. sarmentosum withered after rapid reduction. At first, photosynthesis, stomatal conductance and transpiration rate showed high activity, but they lowered as the plant body closed stomata owing to the decrease in volumetric water content. Measuring antioxidants showed that when drought stress increased, the amount of antioxidants grew as well. However, when high moisture stress was maintained, this compound was continuously consumed. Therefore, the variation of antioxidants was considered possible for use as one of the indicators of drought tolerance evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1200-1206
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• 2015

The major target for drug discovery, G-protein coupled receptor (GPCR) is involved in many physiological activities and related to various diseases and disorders. Among experimental techniques relating to the GPCR drug discovery process, various cell-based screening methods are influenced by cell conditions used in the overall process. Recently, the utilization of frozen cells is suggested in terms of reducing data variation and cost-effectiveness. The aim of this study is to evaluate various conditions in cell freezing such as temperature conditions and storage terms. The stable cell lines for calcium sensing receptor and urotensin receptor were established followed by storing cultured cells at $-80^{\circ}C$ up to 4 weeks. To compare with cell stored at liquid nitrogen, agonist and antagonist responses were recorded based on the luminescence detection by the calcium induced photoprotein activation. Cell signals were reduced as the storage period was increased without the changes in $EC_{50}$ and $IC_{50}$ values $EC_{50}:3.46{\pm}1.36mM$, $IC_{50}:0.49{\pm}0.15{\mu}M$). In case of cells stored in liquid nitrogen, cell responses were decreased comparing to those in live cells, however changes by storage periods and significant variations of $EC_{50}/IC_{50}$ values were not detected. The decrease of cell signals in various frozen cells may be due to the increase of cell damages. From these results, the best way for a long-term cryopreservation is the use of liquid nitrogen condition, and for the purpose of short-term storage within a month, $-80^{\circ}C$ storage condition can be possible to adopt. As a conclusion, the active implementation of frozen cells may contribute to decrease variations of experimental data during the initial cell-based screening process.