Effect of pH on Calcium-Activated Potassium Channels in Pulmonary Arterial Smooth Muscle Cells of the Rabbit

Lee, Suk-Ho,Ho, Won-Kyung,Earm, Yung-E The Korean Physiological Society 1991 대한생리학회지 Vol.25 No.1

Single smooth muscle cells of the rabbit pulmonary artery were isolated by treatment with collagenase and elastase. Using the patch clamp technique, potassium channel activity was recorded from the inside-out membrane patch. The channel had a sin히e channel conductance of about 360 pS in symmetrical concentration of K on both sides of the patch, 150 mM, and had a linear current-voltage relationship. During the application of 10 mM tetraethylammonium (TEA) to the intracellular membrane surface, the amplitude of single channel current was reduced and very rapid flickering appeared. The open probability $(P_0)$ of this channel was increased by increasing positivity of the potential across the patch membrane, with e-fold increase by 20 mV depolarization, and by increasing the internal $Ca^{2+}$ concentration. These findings are consistent with those of large conductance Ca-activated K channels reported in other tissues. But the shortening of the mean open time by increasing $[Ca^{2+}]_i$, was an unexpected result and one additional closed state which might be arisen from a block of the open channel by Ca binding was suggested. The $P_0-membrane$ potential relationship was modulated by internal pH. Decreasing pH reduced $P_0$. Increasing pH not only increased $P_0$ but also weakened the voltage dependency of the channel opening. The modulation of Ca-activated K channel by pH was thought to be related to the mechanism of regulation of vascular tone by the pH change.

임파유통에 영향을 주는 인자에 관한 실험적 연구

김기환,엄융의,Kim, Ki-Whan,Earm, Yung-E 대한생리학회 1975 대한생리학회지 Vol.9 No.1

Various factors influencing the lymph flow from thoracic duct were investigated in an attempt to evaluate their contributing degree and the mechanisms. Sixteen mongrel dogs weighing between 10 and 16 kg were anesthetized and polyethylene catheters were inserted into the thoracic duct and femoral veins. Arterial blood pressure, heart rate, central venous pressure, lymph pressure and lymph flow were measured under various conditions. Electrical stimulation of left sciatic nerve, stepwise increase of central venous pressure, manual application of rhythmical depressions onto abdomen, injection of hypertonic saline solution and histamine infusion were employed. Measurement of cental venous pressure was performed through the recording catheter inserted into abdominal inferior vena cava. Changes in central venous pressure were made by an air-ballooning catheter located higher than the tip of the recording catheter in the inferior vena cava. Lymph flow from thoracic duct was measured directly with a graduated centrifuge tube allowing the lymph to flow freely outward through the inserted cannula. The average side pressure of thoracic lymph was $1.1\;cmH_2O$ and lymph flow was 0.40 ml/min or 1.9 ml/kg-hr. Hemodynamic parameters including lymph flow were measure immediately before and after (or during) applying a condition. Stimulation of left sciatic nerve with a square wave (5/sec, 2 msec, 10V) caused the lymph flow to increase 1.4 times. The pattern of lymph flow from thoracic duct was not continuous throughout the respiratory cycle, but was continuous only during Inspiration. Slow and deep respiration appeared to increase the lymph flow than a rapid and shallow respiration. Relationship between central venous pressure and the lymph flow revealed a relatively direct proportionality; Regression equation was Lymph Flow (ml/kg-hr)=0.09 CVP$(cmH_2O)$+0.55, r=0.67. Manual depressions onto the abdomen in accordance with the respiratory cycle caused the lymph flow to increase most remarkably, e.g,. 5.5 times. The application of manual depressions showed a fluctuation of central venous pressure superimposed on the respiratory fluctuation. Hypertonic saline solution (2% NaCl) administered Intravenously by the amount of 10 m1/kg increased the lymph flow 4.6 times. The injection also increased arterial blood pressure, especially systolic Pressure, and the central venous pressure. Slow intravenous infusion of histamine with a rate of 14-32 ${\mu}g/min$ resulted in a remarkable increase in the lymph flow (4.7 times), in spite of much decrease in the blood pressure and a slight decrease in the central venous pressure.

토끼 동방결절에서의 완만내향전류(i_si)에 관한 연구

안광필(Ahn, Kwang-Pil),이영균(Lee, Young-Kyun),엄융의(Earm, Yung-E),김우겸(Kim, Woo-Gyeum) 대한생리학회 1986 대한생리학회지 Vol.20 No.2

The voltage clamp studies were undertaken to elucidate the properties of the slow inward current, i_si in the small preparations of the rabbit sinoatrial node. The slow inward current, i_si which is known to be responsible for the late one-third of pacemaker potential and whole range of upstroke phase of action potential was analysed with the effects of isoprenaline, cobalt, ouabain and higenamine. The results obtained are as follows; 1) Voltage of SA node preparation was held at zero current level, usually-40mV and the slow inward current, i_si was activated by depolarizing clamp pulses. Peak values of i_si in steady state were at -10±0mV in most preparations. 2) Isoprenaline, β-agonist increased i_si and no shift was noticed in voltage-dependency. 3) Cobalt ion in the concentration of 1 mM abolished is, in entire range of membrane potential and the difference of two current levels before and after Co²⁺ treatment could be considered as pure i_si magnitude. 4) In the therapeutic concentration of ouabain (5 X 10^-8M) slightly increased is, and reduced the time to reach the peak value. 5) Higenamine (10^-6M) changed the configurations of action potential (i. e. rapid upstroke phase and notch in the spike) and increase spontaneous rate. It also increased is, and the effect of higenamine was blocked β-blocker, propranolol (10^-6M).

시스템 생물학과 한의학 연구

엄융의(Yung E Earm) 한의병리학회 2016 동의생리병리학회지 Vol.30 No.6

토끼 동방결절에서 완만내향전류의 Slow Component에 관한 연구

엄융의(Earm, Yung-E),김기환(Kim, Ki-Whan),황상익(Hwang, Sang-Ik) 대한생리학회 1984 대한생리학회지 Vol.18 No.1

The second inward current (i_si) was studied by the two microelectrode voltage clamp technique in the sino-atrial node of the rabbit. The slow component (i_si,2) of the second inward current was sometimes identified and i_si behaved as if it were a mixture of two currents. We analysed the (i_si,2) in relation to membrane potential and frequency of voltage clamp pulses. 1) Membrane was held at -40mV which was usually found to be zero current level. When depolarizing pulses were applied, the slow inward current i_si was activated. 2) It was shown that there are three categories of the i_si activation by the low level of depolarizing clamp pulses. Moderately fast inward current with single component was developed in most cases in the presence of tetrodotoxin(TTX). But sometimes there was two separate components of i_si activation in the peak level and the time course. Thirdly the only slow component of i_si was found in rare cases. 3) The activation of (i_si,2) was dependent upon membrane potential. The i_si shows two separate peaks during clamp depolarizations and higher clamp pulses lead to fusion of the peaks. 4) The i_si,2 activation showed that it decreased with repetitive clamp pulses and it was more evident in higher frequencies(2Hz)(negative staircase).

Acidic pH-activated Cl<SUP>−</SUP> Current and Intracellular Ca<SUP>2+</SUP> Response in Human Keratinocytes

Su Jung Park,Won Woo Choi,Oh Sang Kwon,Jin Ho Chung,Hee Chul Eun,Yung E Earm,Sung Joon Kim 대한생리학회-대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.4

The layers of keratinocytes form an acid mantle on the surface of the skin. Herein, we investigated the effects of acidic pH on the membrane current and [Ca²⁺]_c of human primary keratinocytes from foreskins and human keratinocyte cell line (HaCaT). Acidic extracellular pH (pH_e≤5.5) activated outwardly rectifying Cl⁻ current (I_Cl,pH) with slow kinetics of voltage-dependent activation. I_Cl,pHwas potently inhibited by an anion channel blocker 4,4`-diisothiocyanostilbene-2,2`-disulphonic acid (DIDS, 73.5% inhibition at 1ՌM). I_Cl,pHbecame more sensitive to pH_e by raising temperature from 24^oC to 37^oC. HaCaT cells also expressed Ca²⁺-activated Cl⁻ current (I_Cl,Ca), and the amplitude of I_Cl,Ca was increased by relatively weak acidic pH_e (7.0 and 6.8). Interestingly, the acidic pH_e (5.0) also induced a sharp increase in the intracellular [Ca²⁺] (⁘[Ca²⁺]_acid) of HaCaT cells. The ⁘[Ca²⁺]_acid was independent of extracellular Ca²⁺, and was abolished by the pretreatment with PLC inhibitor, U73122. In primary human keratinocytes, 5 out of 28 tested cells showed ⁘[Ca²⁺]_acid. In summary, we found I_Cl,pH and ⁘[Ca²⁺]_acid in human keratinocytes, and these ionic signals might have implication in pathophysiological responses and differentiation of epidermal keratinocytes.

망간 이온이 개구리 심방근의 막전압 및 수축력에 미치는 영향

嚴隆義,金典,嚴大鎔,金基煥,南基鏞 서울大學校 1977 서울醫大學術誌 Vol.18 No.1

대사성 산증 및 알칼리증에 있어서 SCN 공간의 변화

엄륭의,남기용,Earm, Yung-E,Nam, Kee-Yong 대한생리학회 1971 대한생리학회지 Vol.5 No.2

Thiocyanate space was determined in 23 bilaterally nephrectomized rabbits in acute metabolic acidosis and alkalosis. Acid-base disturbances were induced by the infusion of 0.3 N HCI or 0.3 N NaOH solution intravenously with the rate of 1 ml/min for 40 to 60 minutes. The blood pressure was monitored throughout the experiment and no changes in blood pressure was confirmed. The following results were obtained. 1. In the saline infused control rabbits, PH was 7.385 with negligible change in pH after the infusion, SCN space was 23.6% of body weight. 2. In the metabolic acidosis group, pH dropped from 7.417 to 7 130 and SCN space was 22.8% of body weight and suggested a negligible change in the extracellular space volume. 3. In the metabolic alkalosis group, pH increased from 7.393 to 7.478 and SCN space was 25.7% of body weight which confirmed a significant increase in the extracellular space volume.

개구리 대동맥의 활동전압 및 Pacemaker 전압에 관한 연구

엄융의,성호경,Earm, Yung-E,Sung, Ho-Kyung 대한생리학회 1982 대한생리학회지 Vol.16 No.2

The frog truncus arterious were studied with conventional glass microelectrode technique in order to elucidate the underlying mechanism of spontaneous pacemaker activity. The analyses were focussed on the ionic nature of pacemaker current by changing the concentrations of extracellular $K^+$ and, $Na^+$, or by using blockers of K- and Ca-current and chronotropic transmitters. 1) The action potential of the spontaneously active truncus arteriosus has some characteristic feature of maximal distolic potential ranged from -65 to -75 mV, resting potential from -45 to -50 mV and overshoot voltage about +30 mV, respectively. Duration of the action potential taken from rapid upstroke to maximal diastolic potential was about 600 msec. Usual discharge rate was $25{\sim}30/min$ at room temperature $(18{\sim}20^{\circ}C)$. 2) The sensitivity of the resting membrane potential to change extracellular potassium concentrations $(0{\sim}12\;mM)$ was relatively low. Transient hyperpolarization was appeared in the 12 mM K Ringer after 10 min exposure to 0 mM K and it could be related to Na-pump reactivation by high potassium. 3) Reduction of extracellular sodium concetrations diminished the amplitude and frequency of the action potential. In Ringer solution containing 30% Na (substituted by equimolar Tris), spontaneous activity stopped but reappeared as very slow and small action potential. There was no spotaneous activity in zero Na Ringer solution. 4) Caesium(10 mM), K-current blocker decreased the frequency of the action potential and also pacemaker depolarization. Manganese (2 mM) known to be Ca-current antagonist, blocked spontaneous activity completely. 5) Adrenaline and acetylcholine had no chronotropic effect. But adrenaline increased the duration of plateau phase and the magnitude of the action potential in the follower cell. It is concluded that K-, Na-and Ca-current components are involved in the genesis of spontaneous activity of the frog truncus arteriosus like cardiac pacemaker tissues. But the insensitivity of truncus arteriosus to adrenaline and acetylcholine indicates that there are some different control mechanisms of spontaneous rhythm in two tissues.

Effects of Adrenaline, Acetylcholine, Ca^(++) and K^(+) on the conduction through the SA Node in the Rabbit

Ahn, Cheol-Soo,Earm, Yung-E,Sung, Ho-Kung Seoul National University 1988 The seoul journal of medicine Vol.29 No.3