Calcium Current in the Unfertilized Egg of the Hamster

Haan, Jae-Hee,Cho, Soo-Wan,Yang, Young-Sun,Park, Young-Geun,Park, Hong-Gi,Chang, Gyeong-Jae,Kim, Yang-Mi,Park, Choon-Ok,Hong, Seong-Geun The Korean Physiological Society 1994 대한생리학회지 Vol.28 No.2

The presence of a calcium current $(i_{Ca^{2+}})$ passed via a specific channel was examined in the unfertilized hamster egg using the whole-cell voltage clamp technique. Pure inward current was isolated using a $Ca^{2+}-rich$ pipette solution containing 10 mM TEA. This current was independent of external $Na^+$ and was highly sensitive to the $Ca^{2+}$ concentration in the bathing solution, indicating that the inward current is carried by $Ca^{2+}$. The maximal amplitude was $-4.12{\pm}0.58nA\;(n=12)$ with 10mM $Ca^{2+}$ at -3OmV from a holding potential of -8OmV. This current reached its maximum within 20ms beyond -3OmV and decayed rapidly with an inactivation time constant $({\tau})$ of 15ms. Activation and inactivation of this $i_{Ca^{2+}}$ was steeply dependent on the membrane potential. The $i_{Ca^{2+}}$ began to activate at the lower voltage of -55 mV and reached its peak at -35 mV, being completely inactivated at potentials more positive than -40 mV. These result suggest that $i_{Ca^{2+}}$ in hamster eggs passes through channels with electrical properties similar to low voltage-activated T-type channels. Other results from the present study support this suggestion; First, the inhibitory effect of $Ni^{2+}\;(IC_{50}=13.7\;{\mu}M)$ was more potent than $Cd^{2+}\;(IC_{50}=123\;{\mu}M)$. Second, $Ba^{2+}$ conductance was equal to or below that of $Ca^{2+}$. Third, $i_{Ca^{2+}}$ in hamster eggs was relatively insensitive to nifedipine $(IC_{50}=96.6\;{\mu}M)$, known to be a specific t-type blocker. The physiological role of $i_{Ca^{2+}}$ in the unfertilized hamster eggs remains unclear. Analysis from steady-state inactivation activation curves reveals that only a small amount of this current will pass in the voltage range $(-70{\sim}-30\;mV)$ which partially overlaps with the resting membrane potential. This current has the property that it can be easily activated by a weak depolarization, thus it may trigger a certain kind of a intracellular event following fertilization which may cause oscillations in the membrane potential.

Regulatory Action of ß-adrenergic Agonist and 8-bromocyclic AMP on Calcium Currents in the Unfertilized Mouse Eggs

Haan. Jae-Hee,Cheong. Seung-Jin,Kim. Yang-Mi,Park. Choon-Ok,Hong. Seong-Geun 대한생리학회 1993 대한생리학회지 Vol.27 No.2

There are many report suggesting that influx and intracellular calcium concentration ([Ca²⁺]_i) are related to cell signalling in various cells. However, it has not been reported that calcium channel activation is affected by the substances involved in signal transduction pathways in the mouse eggs. In this study, the effects of isoprenaline (ISP) and cyclic AMP on calcium influx through calcium channels were investigated to show their relationship with the signal transduction process in unfertilized mouse eggs. Using whole cell voltage clamp techniques, calcium currents, elicited by the depolarizing pulses of 300 ms duration (from -50 mV to 50 mV in 10 mV increments) from a holding potential of -80 mV, were recorded. The current-voltage (I-V) relation of calcium currents was shown to be bell-shaped; the current began to activate at -50 mV and reached its maximum (-1.33±0.16 nA: mean±S.E., n=7) at -10 mV, then decayed at around 50 mV. Calcium currents were fully activated within 7 ms ~ 20 ms and completely inactivated 200 ms after onset of the step pulse. ISP within the concentration ranges of 10^-8 M ~ 10^-4 M dose-dependently increased the amplitude calcium current. The permeable cyclic AMP analogue,8-bromocyclic AMP, also increased its maximal amplitude by 46ft at 10^-5 M, while protein kinase inhibitor (PKI), which is known to inhibit 0.02 phosphorylating units of cyclic AMP-dependent protein kinase (PKA) per microgram decreased calcium currents. Currents recorded in the presence of PKI were resistant to increase by the application of 10^-5 M. Also, PKI inhibited the calcium current increase elicited by ISP treatment. These results suggest that β-adrenergic regulation of the calcium channel is mediated by the cAMP-dependent protein kinase. This signal transduction pathway might play a role in regulating [Ca²⁺]_i, level due to the increase of calcium influx in mouse eggs.

Regulatory Action of $\beta-adrenergic$ Agonist and 8-bromocyclic AMP on Calcium Currents in the Unfertilized Mouse Eggs

Haan, Jae-Hee,Cheong, Seung-Jin,Kim, Yang-Mi,Park, Choon-Ok,Hong, Seong-Geun The Korean Physiological Society 1993 대한생리학회지 Vol.27 No.2

There are many report suggesting that influx and intracellular calcium concentration $([Ca^{2+}]_i)$ are related to cell signalling in various cells. However, it has not been reported that calcium channel activation is affected by the substances involved in signal transduction pathways in the mouse eggs. In this study, the effects of isoprenaline (ISP) and cyclic AMP on calcium influx through calcium channels were investigated to show their relationship with the signal transduction process in unfertilized mouse eggs. Using whole cell voltage clamp techniques, calcium currents, elicited by the depolarizing pulses of 300 ms duration (from -50 mV to 50 mV in 10 mV increments) from a holding potential of -80 mV, were recorded. The current-voltage (I-V) relation of calcium currents was shown to be bell-shaped; the current began to activate at -50 mV and reached its maximum $(-1.33{\pm}0.16\;nA:\;mean{\pm}S.E.,\;n=7)$ at -10 mV, then decayed at around 50 mV. Calcium currents were fully activated within $7\;ms{\sim}20\;ms$ and completely inactivated 200 ms after onset of the step pulse. ISP within the concentration ranges of $10^{-8}\;M{\sim}10^{-4}\;M$ dose-dependently increased the amplitude calcium current. The permeable cyclic AMP analogue,8-bromocyclic AMP, also increased its maximal amplitude by 46ft at $10^{-5}\;M$, while protein kinase inhibitor (PKI), which is known to inhibit 0.02 phosphorylating units of cyclic AMP-dependent protein kinase (PKA) per microgram decreased calcium currents. Currents recorded in the presence of PKI were resistant to increase by the application of $10^{-5}\;M$. Also, PKI inhibited the calcium current increase elicited by ISP treatment. These results suggest that $\beta-adrenergic$ regulation of the calcium channel is mediated by the cAMP-dependent protein kinase. This signal transduction pathway might play a role in regulating $[Ca^{2+}]_i$, level due to the increase of calcium influx in mouse eggs.

Kinematic and Dynamic Analyses of Human Arm Motion

( Jung Hee Kim ),( Sung Ho Cho ),( Choong Ho Lee ),( Jae Woong Haan ),( Heon Hwang ) 한국농업기계학회 2013 바이오시스템공학 Vol.38 No.2

Purpose: Determining an appropriate path is a top priority in order for a robot to maneuver in a dynamically efficient way especially in a pick-and -place task. In a non-standardized work environment, current robot arm executes its motion based on the kinematic displacements of joint variables, though resulting motion is not dynamically optimal. In this research we suggest analyzing and applying motion patterns of the human arm as an alternative to perform near optimum motion trajectory for arbitrary pick-and-place tasks. Methods: Since the motion of a human arm is very complicated and diverse, it was simplified into two links: one from the shoulder to the elbow, and the other from the elbow to the hand. Motion patterns were then divided into horizontal and vertical components and further analyzed using kinematic and dynamic methods. The kinematic analysis was performed based on the D-H parameters and the dynamic analysis was carried out to calculate various parameters such as velocity, acceleration, torque, and energy using the Newton-Euler equation of motion and Lagrange′s equation. In an attempt to assess the efficacy of the analyzed human motion pattern it was compared to the virtual mechanical and created by the joint interpolation method. Results: To demonstrate the efficacy of the human arm motion mechanical and dynamical analyses were performed, followed by the comparison with the virtual robot motion path that was created by the joint interpolation method. Consequently, the human arm was observed to be in motion while the elbow was bent. In return this contributed to the increase of the manipulability and decrease of gravity and torque being exerted on the elbow. In addition, the energy required for the motion decreased. Such phenomenon was more apparent under vertical motion than horizontal motion patterns, and in shorter paths than in longer ones. Thus, one can minimize the abrasion of joints by lowering the stress applied to toe bones, muscles, and joints. From the perspectives of energy and durability, the robot arm will be able to utilize its motor most effectively by adopting the motion pattern of human arm. Conclusions: By applying the motion pattern of human arm to the robot arm motion, increase in efficiency and durability is expected, which will eventually produce robots capable of moving in an energy-efficient manner.

Modulatory Effect of the Tyrosine Kinase and Tyrosine Phosphatase on the ACh-activated K₊ Channel in Adult Rat Atrial Cells

Chang. Kyeong-Jae,Rhie. Sang-Ho,Heo. Ilo,Kim. Yang-Mi,Haan. Jae-Hee,Hong. Seong-Geun 대한생리학회 1996 대한생리학회지 Vol.30 No.2

Acetylcholine (ACh) activates the inwardly rectifying muscarinic K⁺ channel in rat atrial cells via pertussis toxin (PTX)-sensitive G-protein (G_k) coupled with the muscarinic receptor (mAChR). Although this K⁺ (K_ACh) channel function has reported to be modulated by the phosphorylation process, a kinase and phosphatase involved in these processes are still unclear. Since either PKA or PKC was not effective on this ATP-modulation, the present study examined the possible involvement of the protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP) in the function of the K_ACh Channel. In the inside-out (I/O) patch preparation excised from the adult rat atrial cell, when activated by 10 μM ACh in the pipette and 100 μM GTP in the bath, the mean open time (τ_o) and the channel activity (K_ACh) was 1.13 ms (n=5) and 0.19 (n=6), respectively. Following the application of 1 mM ATP into the bath, τ_o increased by 34% (1.54 ms, n=5) and K_ACh by 66% (0.28, n=6). Channel function elevated by ATP was lasted after washout of ATP. However, this ATP-induced increase in the K_ACh channel function did not occur in pretreated cells with genistein (50 ~ 100 μM), a selective PTK inhibitor, but occurred in pretreated cells with equimolar daidzein, a negative control of the genistein. On the contrary, PTP which acts on tyrosine residue conversely reversed both ATP-induced increased τ_o by 32% (1.20 ms, n=3) and K_ACh by 41% (0.15, n=3), respectively. Taken together, these results suggest that K_ACh channel may, at least partly, be regulated by the tyrosyl phosphorylation, although it is unclear where this process exerts on the muscarinic signal transduction pathway comprising the mAChR-G_k-the K_ACh channel.

1/10 축소모형을 이용한 소공연장의 흡음재와 확산체의 적용위치에 따른 음향성능 비교

김태희,박찬재,박지훈,한찬훈,Kim, Tae-Hee,Park, Chan-Jae,Park, Ji-Hoon,Haan, Chan-Hoon 한국음향학회 2015 韓國音響學會誌 Vol.34 No.2

본 연구는 흡음재와 확산체의 적용위치가 소공연장의 음향성능에 미치는 영향에 대하여 알아보았다. 서울의 대학로의 2000년 이후 개관한 36곳의 공연장의 평균크기로 소공연장의 표준모델을 설정하여 연구를 진행하였다. 본 연구에서는 마감재 적용유효면적이 가장 작은 뒷벽을 기준으로 마감재의 적용면적을 산출하고, 마감재의 적용위치별 음향성능 변화를 분석하기 위하여 천장, 측벽의 적용위치를 전반부, 중반부, 후반부로 구분하여 총 8가지의 경우를 만들어, 1/10 축소모형실험을 진행하였다. 사용된 음향지표는 잔향시간(Reverberation Time, RT), 초기감쇠시간(Early Decay Time, EDT), 음악명료도(Clarity, C80), 음성명료도(Definition, D50), 음성전달지수(Speech Transmission Index, STI)를 이용하였다. 실험결과 마감재의 적용위치 변화는 소리의 울림에 양과 관련된 음향인자인 잔향시간, 초기감쇠시간 은 최소 변화 감지폭에 의한 (Just Noticeable Difference, JND) 평가시 변화가 뚜렷하게 나타났고, 소리의 명료도와 관련된 인자인 음악명료도, 음성명료도, 음성전달지수는 변화가 거의 없는 것으로 나타났다. 짧은 잔향시간을 얻고자 하는 경우 흡음재와 확산체 적용시 모두 측벽부분을 통한 잔향시간 조절이 가장 효과적이며, 측벽 전반부가 가장 짧은 잔향시간을 얻을 수 있는 위치인 것으로 나타났다. This study investigated how the location of sound absorptive materials and sound diffusers affects the acoustic performance of small auditoriums. It was conducted for a standard model established with the averaged dimension of 36 auditoriums which had opened since 2000 in Daehak-ro, Seoul. In this study, the installation area of finishing materials was calculated upon a back wall which had the smallest installation effective area of finishing materials. To analyze the changes of acoustic performance according to installation location of finishing materials, experiments were carried out using the 1/10 down scale models for 8 cases which were made by classifying the installation location of ceiling and side wall into the front, middle and rear part.The used acoustic parameters were reverberation time (RT), early decay time (EDT), clarity (C80), definition (D50) and speech transmission index (STI). In result, the index related to the amount of reverberant sound (RT, EDT) showed the great changes when evaluating it through just noticeable difference (JND), but the one related to clarity (C80, D50, STI) hardly indicated the changes. In case to obtain short reverberation time, it was most effective to control reverberation time through the side walls when installing sound absorptive and diffusive materials, and side wall front was the location which could get the shortest reverberation time.

Voltage-Dependent Ionic Currents and Their Regulation by GTP and Phorbol Ester in the Unfertilized Eggs of Mouse and Hamster

Kim Ik-Hyun,Kim Yang-Mi,Haan Jae-Hee,Park Choon-Ok,Hong Seong-Geun 대한생리학회 1993 대한생리학회지 Vol.27 No.1

Low-Voltage Activated Ca²⁺ Current Carried via T-Type Channels in the Mouse Egg

Yang. Young-Sun,Park. Young-Geun,Cho. Soo-Wan,Cheong. Seung-Jin,Haan. Jae-Hee,Park. Choon-Ok,Hong. Seong-Geun 대한생리학회 1993 대한생리학회지 Vol.27 No.1

Most of voltage operated Ca²⁺ channels can be divided into three types (T-, N-, and L-type), according to the electrical and pharmacological properties. Their distribution is closely related to cell specific functions. Properties of the voltage activated Ca²⁺ current in mouse eggs were examined to classify channel types and to deduce the function by using whole cell voltage clamp technique. Ca²⁺ currents appeared below -40 mV and reached a maximum at -15 mV (half maximum was -31 mV), then decayed rapidly (inactivation time constant τ=28.2±9.59 ms at -10 mV within 50 ms after the onset of step depolarization. Activation and inactivation of the Ca²⁺ channel was steeply dependent on voltage, in a relatively low range of -70 mV ~ -10 mV, half maximum of activation was -31 mV and that of inactivation was -39 mV, respectively. This current was not decreased significantly by nifedipine, a specific dihydropyridine Ca²⁺ channel blocker in the range of 1 μM to 100μM. The inhibitory effect of Ni²⁺ on Ca²⁺ current was greater than that of Cd²⁺. The conductance of Ba²⁺ through the channel was equal to or lower than that of Ca²⁺ These results implied that Ca²⁺ current activated at a lower voltage in the mouse egg is carried via a Ca²⁺ channel with similar properties that of the T-type channel.

심장세포에서 세포내 Ca²⁺ 증가에 의해 활성화되는 Cl^- 통로의 특성과 역할

박춘옥,김양미,한재희,홍성근,Park, Choon-ok,Kim, Yang-mi,Haan, Jae-hee,Hong, Seong-geun 대한수의학회 1994 大韓獸醫學會誌 Vol.34 No.1

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

GS-386이 단일 심근 세포의 Ca²⁺ 전류에 미치는 효과

박춘옥,장경재,김양미,한재희,홍성근,Park, Choon-ok,Chang, Kyeong-jae,Kim, Yang-mi,Haan, Jae-hee,Hong, Seong-geun 대한수의학회 1994 大韓獸醫學會誌 Vol.34 No.1

The effects of the novel compound GS-386 on the calcium current were investigated in rabbit atrial myocytes. The calcium current was recorded during various depolarizations of 200 ms duration from a holding potential of -40 mV using the whole cell patch clamp technique. The calcium current was activated from -30 mV, reached maximum amplitude at +10 mV and almost disappeared at +50 mV. Superfusion of GS-386 led to a reduction of the calcium current amplitude dose-dependently and $ED_{50}$ was $2.5{\times}10^{-7}M$. But the dependence of the calcium current on the membrane potential was not altered by GS-386. The inactivation of the calcium currents showed single exponential curves in both before and after application of GS-386. The inactivation time constants before and after application of GS-386 were almost the same(35 ms and 32.5 ms). The steady-state inactivation curve of the calcium current was not shifted by GS-386. The calcium currents both before and after application of GS-386 recovered completely in 1 sec and the recovery time constants were about 200 ms in both cases. From the above results it is concluded that the novel compound GS-386 has calcium antagonistic property decreasing the calcium current.