• Title/Summary/Keyword: duration of action

Search Result 301, Processing Time 0.034 seconds

A Study on the Utilization of Volunteers in the Visiting Health Services of Health Centers (보건소의 방문보건사업에서 자원봉사자 활용에 관한 연구)

  • 최은숙;정헤선
    • Health Policy and Management
    • /
    • v.10 no.2
    • /
    • pp.103-119
    • /
    • 2000
  • This study is conducted to promote the activation of volunteer activities on the basic of the voluntaarry participation of local by investigating the utillzation of volunteers and analyzing this realted factors in the visiting health services of health centers. Subjects in this study were the whole 245 health centers. Data were collected from April, 12, 1999 to May, 31, 1999, and data for analyses were ones of 41 respondents, which answer " they utilize volunteers in visting health services". The summary of resulth was as follows : 1. In case that the type of health centers is one of county, in case that the number of staff in health center is over 80, in case that model business in not performed, in case that the degree of local financial independence is over 50%, and in case that the location of health centers in not good, there had more of volunteers in visiting health services. 2. 51.2% of analysing health centers answered that the utilization of volunteers has been done since 1998. 56.1% answered that they utillzed volunteers "over 4 hours" per person in a week. The average number of volunteers who was engaged at those visiting health services was 43.3. 3. Most of volinteers were housewives(73.2%). As for the action duration of volunteers. 68.8% answered " under 6 months". 4. As to the tasks of volunter activities, 75.6% were "home services" and 63.4% were "movable bath services". As for the tasks they intend to utilize, 90.2% answered " home services", 73.2% answered "movable health services". 5. Asked abount the purpose in utilizing volunteers, 75.6% answered "to induce the participation og local people". 65.9% answered "to provide various kinds of services". 66.7% provided some kind of education and training for volunteers. 6. Concerming evaluation of performance by volunteers, 90.2% answered " satisfactory". With reagards to the reason for that, 52.9% answered " volunteers can provide kinds of services". and 50.0% answered " volunteers can help local people to care their health". As for the obstacles to the utilization, 51.2% answered " the diffculty of recruitment for volunteers" and 43.9% answered "lack of budget and manpower needed for the utilization of volunteers".lty of recruitment for volunteers" and 43.9% answered "lack of budget and manpower needed for the utilization of volunteers".lunteers&".ot;.

  • PDF

Studies on the Physical and Chemical Denatures of Cocoon Bave Sericin throughout Silk Filature Processes (제사과정 전후에서의 견사세리신의 물리화학적 성질변화에 관한 연구)

  • 남중희
    • Journal of Sericultural and Entomological Science
    • /
    • v.16 no.1
    • /
    • pp.21-48
    • /
    • 1974
  • The studies were carried out to disclose the physical and chemical properties of sericin fraction obtained from silk cocoon shells and its characteristics of swelling and solubility. The following results were obtained. 1. The physical and chemical properties of sericin fraction. 1) In contrast to the easy water soluble sericin, the hard soluble sericin contains fewer amino acids include of polar side radical while the hard soluble amino acid sach as alanine and leucine were detected. 2) The easy soluble amino acids were found mainly on the outer part of the fibroin, but the hard soluble amino acids were located in the near parts to the fibroin. 3) The swelling and solubility of the sericin could be hardly assayed by the analysis of the amino acid composition, and could be considered to tee closely related to the compound of the sericin crystal and secondary structure. 4) The X-ray patterns of the cocoon filament were ring shape, but they disappeared by the degumming treatment. 5) The sericin of tussah silkworm (A. pernyi), showed stronger circular patterns in the meridian than the regular silkworm (Bombyx mori). 6) There was no pattern difference between Fraction A and B. 7) X-ray diffraction patterns of the Sericin 1, ll and 111 were similar except interference of 8.85A (side chain spacing). 8) The amino acids above 150 in molecular weight such as Cys. Tyr. Phe. His. and Arg. were not found quantitatively by the 60 minutes-hydrolysis (6N-HCI). 9) The X-ray Pattern of 4.6A had a tendency to disappear with hot-water, ether, and alcohol treatment. 10) The partial hydrolysis of sericin showed a cirucular interference (2A) on the meridian. 11) The sericin pellet after hydrolysis was considered to be peptides composed with specific amino acids. 12) The decomposing temperature of Sericin 111 was higher than that of Sericin I and II. 13) Thermogram of the inner portioned sericin of the cocoon shell had double endothermic peaks at 165$^{\circ}C$, and 245$^{\circ}C$, and its decomposing temperature was higher than that of other portioned sericin. 14) The infrared spectroscopic properties among sericin I, II, III and sericin extracted from each layer portion of the cocoon shell were similar. II. The characteristics of seriein swelling and solubility related with silk processing. 1) Fifteen minutes was required to dehydrate the free moisture of cocoon shells with centrifugal force controlled at 13${\times}$10$^4$ dyne/g at 3,000 R.P.M. B) It took 30 minutes for the sericin to show positive reaction with the Folin-Ciocaltue reagent at room temperature. 3) The measurable wave length of the visible radiation was 500-750m${\mu}$, and the highest absorbance was observed at the wave length of 650m${\mu}$. 4) The colorimetric analysis should be conducted at 650mu for low concentration (10$\mu\textrm{g}$/$m\ell$), and at 500m${\mu}$ for the higher concentration to obtain an exact analysis. 5) The absorbing curves of sericin and egg albumin at different wave lengths were similar, but the absorbance of the former was slightly higher than that of the latter. 6) The quantity of the sericin measured by the colorimetric analysis, turned out to be less than by the Kjeldahl method. 7) Both temperature and duration in the cocoon cooking process has much effect on the swelling and solubility of the cocoon shells, but the temperature was more influential than the duration of the treatment. 8) The factorial relation between the temperature and the duration of treatment of the cocoon cooking to check for siricin swelling and solubility showed that the treatment duration should be gradually increased to reach optimum swelling and solubility of sericin with low temperature(70$^{\circ}C$) . High temperature, however, showed more sharp increase. 9) The more increased temperature in the drying of fresh cocoons, the less the sericin swelling and solubility were obtained. 10) In a specific cooking duration, the heavier the cocoon shell is, the less the swelling and solubility were obtained. 11) It was considered that there are differences in swelling or solubility between the filaments of each cocoon layer. 12) Sericin swelling or solubility in the cocoon filament was decreased by the wax extraction.. 13) The ionic surface active agent accelerated the swelling and solubility of the sericin at the range of pH 6-7. 14) In the same conditions as above, the cation agent was absorbed into the sericin. 15) In case of the increase of Ca ang Mg in the reeling water, its pH value drifted toward the acidity. 16) A buffering action was observed between the sericin and the water hardness constituents in the reeling water. 17) The effect of calcium on the swelling and solubility of the sericin was more moderate than that of magnecium. 18) The solute of the water hardness constituents increased the electric conductivity in the reeling water.

  • PDF

Occupational Exposure Assessment for Benzene Using Exposure Models (ECETOC TRA and Stoffenmanager) and Applicability Evaluation of Exposure Models in K-REACH (노출 모델의 화평법 적용성: ECETOC TRA와 Stoffenmanager Tier 1 노출 모델을 활용한 벤젠의 작업자 노출 평가)

  • Moon, Joonsik;Ock, Jeongwon;Jung, Uk-Hyun;Ra, Jin-Sung;Kim, Ki-Tae
    • Journal of Environmental Health Sciences
    • /
    • v.44 no.5
    • /
    • pp.460-467
    • /
    • 2018
  • Objectives: The objectives of this study are to estimate the inhalation exposure level of benzene for workers using Tier 1 exposure models ECETOC TRA (European Center for Ecotoxicology and Toxicology of Chemicals Target Risk Assessment) and Stoffenmanager, and to investigate their reliability for exposure assessment in K-REACH. Methods: Two exposure scenarios, 'manufacture of benzene' and 'use as solvents,' were developed for assessment of workers' exposure to benzene. The Process Category (PROC) for ECETOC TRA was collected from the European Chemical Agency (ECHA) registration dossier, and the Activity for Stoffenmanager was converted from PROC using translation of exposure models (TREXMO). The information related to exposure, such as working duration, Respiratory Protective Equipment (RPE), Local Exhaust Ventilation (LEV), and Risk Management Measure (RMM) were classified into high, medium, and low exposure conditions. The risk was determined by the ratio of the estimated exposure and occupational exposure limits of benzene. Results: Under high exposure conditions, the worker exposure level calculated from all PROCs and Activities exceeded the risk level, with the exception of PROC 1 and Activity 1. In the medium exposure condition, PROC 8a, 8b, and 9 and Activity 3, 7, and 8 all exceeded the risk, whereas in the low condition, all PROCs and Activities were determined to be safe. As a result, action corresponding with the low exposure condition is required to reduce the risk of exposure among workers in workplaces where benzene is manufactured or used as a solvent. In addition, the predicted exposure levels derived from the exposure models were lower than measured levels. The exposure levels estimated from Stoffenmanager were more conservative than those from ECETOC TRA. Conclusions: This study demonstrates the feasibility of exposure models for exposure assessment through the example of occupational inhalation exposure assessment for benzene. For more active utilization of exposure models in K-REACH, the exact application of collected information and accurate interpretation of obtained results are necessary.

Comparision of cardiovascular and analgesic effects of epidural administration of medetomidine, medetomidine-buprenorphine and medetomidine-fentanyl in dogs anesthetized with isoflurane (Isofourane으로 마취된 개에 medetomidine, medetomidine-buprenorphine, medetomidine-fentanyl의 경막외 투여 시 심혈관계 반응과 진통효과의 비교)

  • Chang, Hwa-Seok;Kim, Hye-Jin;Choi, Chi-Bong;Lee, Jung-Sun;Kim, Hwi-Yool
    • Korean Journal of Veterinary Research
    • /
    • v.47 no.1
    • /
    • pp.103-115
    • /
    • 2007
  • The aim of this study was to compare the reaction of the cardiovascular system, and the anesthetic effect among 3 experimental groups, epidural administration of medetomidine as a single agent, the combination of buprenorphine and medetomidine, and the combination of fentanyl and medetomidine. Twenty one dogs were anesthetized with isoflurane and allowed to breathe spontaneously. Epidural, arterial, and venous catheters were inserted. The tip of epidural catheter was positioned at the level of the space between the sixth and seventh lumbar vertebra. After a stable plane of anesthesia was achieved, these dogs were each administered one of the following treatments epidurally : medetomidine $10{\mu}g/kg$ (Group M), a combination of medetomidine $5{\mu}g/kg$ and buprenorphine $10{\mu}g/kg$ (Group M/B), and a combination of medetomidine $5{\mu}g/kg$ and fentanyl $10{\mu}g/kg$ (Group M/F). Heart rate (HR), Respiratory rate (RR), End-tidal carbon dioxide (EtCO2), and arterial blood pressure were measured before drug administration (base line) and 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 min postinjection. Blood gas analysis was performed before injection and 5, 15, 25, 35, 45, 60 min postinjection. Isoflurane was discontinued 80 min postinjection and pain/motor function were evaluated up to 260 min postinjection every 15 min. At the early stage of drug introduction (until 5 min), the HR was decreased significantly in all 3 groups compared with base line. In Group M, HR was significantly decreased compared with the other 2 groups. With time (starting 20 min after drug introduction), the HR was decreased significantly in Group M/B in respect to base line. However, no significant difference was seen number-wise in all 3 groups. During 60 min after drug introduction, the systolic, diastolic and mean arterial pressures were highest in Group M and lowest in Group M/F. Among 3 groups, drug action and motor loss duration were longest in Group M/F. Analgesic effect observed in the M/F group was the most prominent and long-lasting, compared to those seen in the other 2 groups. Given the fact that the recovery of motor function takes place in a short period of time after analgesic effects disappeared, additional use of M/F depending on the patient's condition would be a good way to achieve effective pain management. However, proper care should be taken to ensure the function of cardiovascular system in the patient because the administration of M/F under isoflurane anesthesia results in a significant decline in arterial blood pressure ($65{\pm}10mmHg$).

Characterization of Voltage-Gated Potassium Currents in Dorsal Root Ganglion Neurons of Neonatal Rats (신생흰쥐 척수후근신경절 세포에서 전압의존성 $K^+$ 전류의 동정)

  • Kim, Ji-Mok;Jung, Sung-Jun;Kim, Sang-Jeong;Kim, Jun
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.1 no.6
    • /
    • pp.613-624
    • /
    • 1997
  • Dorsal root ganglion (DRG) is composed of neuronal cell bodies of primary afferents with diverse functions. Various types of ion channels present on DRG neurons may reflect those functions. In the present study, voltage-gated potassium currents in DRG neurons of neonatal rats were characterized by whole-cell voltage clamp method. Two types of delayed rectifier and three types of transient potassium currents were identified according to their electrophysiological properties. The delayed rectifier currents were named $I_{Ke}$ (early inactivating) and $I_{K1}$ (late inactivating). Steady state inactivation of $I_{Ke}$ began from -100 mV lasting until -20 mV. $I_{K1}$ could be distinguished from $I_{Ke}$ by its inactivation voltage range, from -70 mV to +10 mV. Three transient currents were named $I_{Af}$ (fast inactivation), $I_{Ai}$ (intermediate inactivation kinetics), and $I_{As}$ (slow inactivation). $I_{Af}$ showed fast inactivation with time constant of $10.6{\pm}2.0$ msec, $I_{Ai}$ of $36.9{\pm}13.9$ msec, and $I_{As}$ of $60.6{\pm}2.9$ msec at +30 mV, respectively. They also had distinct steady state inactivation range of each. Each cell expressed diverse combination of potassium currents. The cells most frequently observed were those which expressed both $I_{K1}$ and $I_{Af}$, and they had large diameters. The cells expressing $I_{Ke}$ and expressing $I_{Ke}$, $I_{Ai}$, and $I_{As}$ usually had small diameters. Judging from cell diameter, capsaicin sensitivity or action potential duration, candidates for nociceptor were the cells expressing $I_{Ke}$, expressing $I_{Ke}$ and $I_{Ai}$, and expressing $I_{Ke}$ and $I_{As}$. The types and distribution of potassium currents in neonatal rat DRG were similar to those of adult rat DRG (Gold et al, 1996b).

  • PDF

Risperidone as a Janus in Mood Disorder (기분장애에서 risperidone의 양면성)

  • Yoon, Doh Joon
    • Korean Journal of Biological Psychiatry
    • /
    • v.4 no.2
    • /
    • pp.198-210
    • /
    • 1997
  • To examine the double-faced thymoleptic(antidepressant and antimanic) effects of risperidone in mood disorders, this article reviews the psychotropic-induced mania, thymoleptic effects of antipsychotics, therapeutic effects of risperidone and risperidone(RIS)-induced mania(RIM) in mood disorders, risk factors of RIM, possible neurochemical mechanism of these thymoleptic effects, pathophysiological and clinical significance of thymoleptic effects, and suggestive clinical guideline of RIS in mood disorders. RIS appeared effective for bipolar disorder at a lower dose than that recommended for schizophrenia, especially in the cases of maintenance of mood stabilizers, and gradual titration from low doses. Manic induction/exacerbation can occur by chance during RIS treatment in mood disorders, schizoaffective disorders, and schizophrenias. The possible risk factors for RIM are refractory mood disorder, especially in bipolar I disorder with poor initial response ; refractory schizoaffective disorders, especially in bipolar type with poor initial response ; refractory chronic schizophrenias, especially with initial responses ; psychotic features ; higher initial doses ; rapid titration ; combined therapy with antidepressants in refractory depression ; and RIS monotherapy in mania/hypomania. RIS is a drug that preferentially block 5-HT2 receptors. The effects of low dose are due mainly to the blockade of 5-HT2 receptors. There are more gradual increase in D2 blockade with increasing dose and this D2 blocking properties become apparent at higher doses. This may be related to a modulation of dopaminergic transmission by 5-HT2 antagonism at lower doses with the direct action of RIS on DA receptors coming into play at higher dose. The serotonergic antagonistic effect may be important for its effects on depressive symptoms. This, together with adequate blo-ckade of D2 receptors, may not necessarily lead to destabilization of mood disorder, but rather to more therapeutic effects. Therefore, this dose-receptor affinity relationship with both antidepressant and antimanic effects according to treatment duration can explain a continuum of antidepressant effect, antimanic effect, behavioral stimulation, and manic/hypomanic induction/exacerbation. It was the recognition of a useful psychiatric side effects by a thoughtful observer with fertile minds that led to their ultimate utilization as psychotropic drugs, i.e., phenothiazine, MAOI, TCA, and lithium. And, in vivo pharmacological challenge by novel psychotropics, as a neurochemical probe, with more specific actions is a useful tool to select pharmacologically homogeneous subgroup of the same phenotypical(clinical) condition, to further study the unknown underlying pathogenesis of various mental illnesses. Finally, RIS may be a useful alternative or adjunctive drug for patients with mood disorders without psychotic features or refractory to treatment with standard antipsychotic drugs. The more conservative doses(tirated slowly from 1-3 mg/d) of RIS, and maintenance of mood stabilizer in the cases with risk factors of RIM are recommended in mood disorder.

  • PDF

Effect of Kinetic Degrees of Freedom of the Fingers on the Task Performance during Force Production and Release: Archery Shooting-like Action

  • Kim, Kitae;Xu, Dayuan;Park, Jaebum
    • Korean Journal of Applied Biomechanics
    • /
    • v.27 no.2
    • /
    • pp.117-124
    • /
    • 2017
  • Objective: The purpose of this study was to examine the effect of changes in degrees of freedom of the fingers (i.e., the number of the fingers involved in tasks) on the task performance during force production and releasing task. Method: Eight right-handed young men (age: $29.63{\pm}3.02yr$, height: $1.73{\pm}0.04m$, weight: $70.25{\pm}9.05kg$) participated in this study. The subjects were required to press the transducers with three combinations of fingers, including the index-middle (IM), index-middle-ring (IMR), and index-middle-ring-little (IMRL). During the trials, they were instructed to maintain a steady-state level of both normal and tangential forces within the first 5 sec. After the first 5 sec, the subjects were instructed to release the fingers on the transducers as quickly as possible at a self-selected manner within the next 5 sec, resulting in zero force at the end. Customized MATLAB codes (MathWorks Inc., Natick, MA, USA) were written for data analysis. The following variables were quantified: 1) finger force sharing pattern, 2) root mean square error (RMSE) of force to the target force in three axes at the aiming phase, 3) the time duration of the release phase (release time), and 4) the accuracy and precision indexes of the virtual firing position. Results: The RMSE was decreased with the number of fingers increased in both normal and tangential forces at the steady-state phase. The precision index was smaller (more precise) in the IMR condition than in the IM condition, while no significant difference in the accuracy index was observed between the conditions. In addition, no significant difference in release time was found between the conditions. Conclusion: The study provides evidence that the increased number of fingers resulted in better error compensation at the aiming phase and performed a more constant shooting (i.e., smaller precision index). However, the increased number of fingers did not affect the release time, which may influence the consistency of terminal performance. Thus, the number of fingers led to positive results for the current task.

Association between Scrub Typhus Outbreaks and Meteorological Factors in Jeollabuk-do Province (전북지역 쯔쯔가무시증 발생과 기후요소의 상호 관련성)

  • Kang, Gong-Unn;Ma, Chang-Jin;Oh, Gyung-Jae
    • Journal of Environmental Health Sciences
    • /
    • v.42 no.1
    • /
    • pp.41-52
    • /
    • 2016
  • Objectives: Scrub typhus is one of the most prevalent vector-borne diseases. It is caused by Orientia tsutsugamushi, which is transmitted when people are bitten by infected chigger mites. This study aims at quantifying the association between the incidence of scrub typhus and meteorological factors in Jeollabuk-do Province over the period 2001-2015. Methods: Reported cases of scrub typhus were collected from the website of the Disease Web Statistical System supported by the Korea Centers for Disease Control and Prevention (KCDC). Simultaneous meteorological data, including temperature, rainfall, relative humidity, and sunshine duration were collected from the website of the National Climate Data Service System by the Korea Meteorological Administration. Correlation and regression analyses were applied to identify the association between the incidence of scrub typhus and meteorological factors. Results: The general epidemiological characteristics of scrub typhus in Jeollabuk-do Province were similar to those nationwide for sex, age, and geographical distribution. However, the annual incidence rate (i.e., cases per 100,000) of scrub typhus in Jeollabuk-do Province was approximately four times higher than all Korea's 0.9. The number of total cases was the highest proportion at 13.3% in Jeonbuk compared to other regions in Korea. The results of correlation analysis showed that there were significant correlations between annual cases of scrub typhus and monthly data for meteorological factors such as temperature and relative humidity in late spring and summer, especially in the case of temperature in May and June. The results of regression analysis showed that determining factors in the regression equation explaining the incidence of scrub typhus reached 46.2% and 43.5% in May and June. Using the regression equation, each 1oC rise in the monthly mean temperature in May or June may lead to an increase of 38 patients with scrub typhus compared to the annual mean of incidence cases in Jeollabuk-do Province. Conclusion: The result of our novel attempts provided rational evidence that meteorological factors are associated with the occurrence of scrub typhus in Jeollabuk-do. It should therefore be necessary to observe the trends and predict patterns of scrub typhus transmission in relation to global-scale climate change. Also, action is urgently needed in all areas, especially critical regions, toward taking steps to come up with preventive measures against scrub typhus transmission.

Studies on the Effects $CCl_4$ on Exorine Pancreas (취외분비선에 미치는 사염화탄소의 영향)

  • Pae, Young-Sook
    • The Korean Journal of Pharmacology
    • /
    • v.11 no.1 s.17
    • /
    • pp.47-53
    • /
    • 1975
  • The metabolism of many drugs and also of steroid hormones is mediated by enzymes located in the microsomal fraction in smooth surfaced endoplasmic reticulum of mammalian liver. The duration and intensity of action of many drugs are largely determined by the speed at which they are metabolized in the body. Repeated administration of phenobarbital results in the induction of enzymes that metabolize a number of drugs. Lee et al. reported that daily administration of phenobarbital in rats significantly increased the activities of amylase in the pancreatobiliary juice, but the concentration of cholate in the bile was significantly lower in the treated group than that in the control group. After animals were treated with $CCl_4$, histological changes were shown in the endoplasmic reticulum, decreased microsomal enzyme activity and decreased hepatic protein synthesis were apparent. The purpose of the present report was to study the interaction between a 'microsomal-stimulating' agent such as phenobarbital and a 'microsomal- depressing' agent such as $CCl_4$ on hepatic and pancreatic functions in rats. The results obtained are summarized as follows: 1. The mortality rate of $CCl_4$ treated group was 34% and was decreased this figure to 15% with phenobarbital pretreatment. 2. In animals treated with phenobarbital the volume of biliary-pancreatic secretion was markedly elevated but the volume was decreased significantly in animals treated with $CCl_4$. 3. Total bilirubin output was elevated markedly in the $CCl_4$ treated group of rats pretreated with phenobarbital. The bilirubin concentration was increased in $CCl_4$ treated group and decreased in the group treated phenobarbital alone. 4. The concentration and total output of cholate in the bile were significantly lower in the all experimental group than control group. 5. In the animals treated with phenobarbital alone and phenobarbital plus $CCl_4$, the activity of lipase in pancreatobiliary juice was elevated, while in the animals treated with $CCl_4$ alone no change was observed. 6. The activity of amylase in the pancreatobiliary juice was decreased in the $CCl_4$ treated group, but elevated markedly in phenobarbital group and also elevated in phenobarbital-$CCl_4$ group. By the above results, it is concluded, when the liver was damaged by $CCl_4$, the exocrine function of pancreas and liver was decreased simultaneously. However, in the animals pretreated with phenobarbital, the toxicity of $CCl_4$ on the liver and pancreas was reduced.

  • PDF

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 Journal of Physiology
    • /
    • v.27 no.2
    • /
    • pp.175-183
    • /
    • 1993
  • 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.

  • PDF