빅데이터 기반 폭염 영향 지역의 공간적 탐색

이상혁(Sang-hyeok Lee),강정은(Jung Eun Kang),배현주(Hyun-joo Bae) 한국방재학회 2022 한국방재학회논문집 Vol.22 No.3

지속적인 기후변화와 도시공간의 변화로 인해 빈도와 강도가 강해지고 있는 폭염의 부정적 영향 저감을 위해서는 영향에 대한 진단과 관련 연구의 수행이 필요하다. 국내에서는 2018년 이례적인 극한기상의 발생 이후 폭염에 대한 관심의 증가로 많은 연구가 수행되었으나, 폭염이 도시민의 생활과 활동에 미치는 영향에 관한 연구는 매우 부족한 실정이다. 이에 본 연구는 폭염의 발생이 도시민의 활동에 미치는 영향을 실증하고, 공간적으로 탐색하고자 하였다. 여름철 인구 빅데이터를 활용하여 폭염 발생일과 대조일 간 활동인구 변화를 대응표본 검정을 통해 통계적으로 검증하였으며, 이들 변화의 지역적 차이를 GIS와 공간군집분석을 활용해 지역 간 차이를 시각화하여 분석하였다. 통계분석 결과 시기에 따라 차이는 있으나 폭염의 발생은 도시민의 활동을 감소시키는 경향을 보였다. 지역 간 활동인구의 변화는 차이를 보였으며, 군집분석 결과 폭염의 발생에도 활동인구가 증가하는 핫스팟은 평일 마포구와 송파구, 강남구 일대, 주말 관악구, 강서구, 은평구 일대에서 나타났다. 반대로 콜드스팟은 평일 서대문구, 강북구, 성북구, 종로구, 중구 일대에서 뚜렷하게 나타났으며, 주말 종로구와 중구, 서초구와 강남구 일대에서 넓게 도출되었다. 이러한 분석 결과는 지역의 특성을 반영한 폭염 대응정책 마련을 위한 기초자료로 활용될 수 있을 것이다. With the increase in frequency and intensity of heatwaves due to continued climate change and changes in urban spaces, research is needed to reduce their negative impacts. In Korea, several studies have been conducted on the subject since the unusual occurrence of extreme weather in 2018; however, as few have focused on the effects of heatwaves on the lives and activities of urban residents, this study investigates these effects and explores their spatial aspects. Using population big data, the changes in the active population on days when heatwaves occurred were statistically verified through a paired-samples test. Additionally, regional variations in changes were analyzed using GIS and spatial cluster analysis. Despite a slight temporal variation, the statistical analysis showed that the occurrence of heatwave is associated with decreased activity among urban residents. There was a difference in the active population between regions, and cluster analysis revealed that some hot spots saw increased activity in the population despite the occurrence of heatwaves, including Mapo-gu, Songpa-gu, and Gangnam-gu on weekdays and Gwanak-gu, Gangseo-gu, and Eunpyeong-gu on weekends. Conversely, the cold spots found included Seodaemun-gu, Gangbuk-gu, Seongbuk-gu, and Jongno-gu on weekdays and Jongno-gu, Jung-gu, Seocho-gu, and Gangnam-gu on weekends. These results can serve as basic data to prepare a heatwave response policy that reflects the characteristics of the region.

A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea

Yong Sung Choi,정성훈,김은선,Eun Sun Kim,Eunhee Lee,Euiseok Jung,So-Yeon Lee,이우령,Hye Sun Yoon,Yong Joo Kim,Ji Kyoung Park,Son Moon Shin,Ellen Ai-Rhan Kim 대한신생아학회 2022 Neonatal medicine Vol.29 No.1

Purpose: Pediatricians have a significant responsibility to educate mothers about the importance of breastfeeding. However, there have been minimal efforts in the courses of resident training in Korea. The purpose of this study is to evaluate the change in knowledge and attitude before and after a 4-week breastfeeding educational intervention among multicenter residents. Methods: Prospective interventional educational research was designed for residents at eight training hospitals in Korea. Institutional reviews were obtained in each hospital. The education curriculum consisted of 14 courses regarding breastfeeding theory and practice. These materials were used to teach pediatric residents for 4 weeks. Knowledge-based tests were administered before the course, and re-tests were administered after the course using different test items of similar levels. Test scores and survey responses were compared before and after the intervention. Results: A total of 73 residents (1st year 20, 2nd year 23, 3rd year 16, and 4th year residents 14) from eight training hospitals completed the intervention. Their average age was 30.3±2.9 years, 17 (23.3%) were male, 22 (30.1%) were married, and eight had more than one child of their own. The mean pre-test score was 61.8±13.4 and the mean post-test score was 78.3±7.5 (P<0.001). The inter-grade difference in the score was significant in the pre-test (P=0.005), but not significant in the post-test (P=0.155). There were more responses of obtaining confidence after the intervention (P<0.001). Conclusion: In our study, pediatric residents showed improvement in their knowledge and confidence level after 4 weeks of the breastfeeding curriculum. This will provide a basis for future policymaking in the training of pediatric residents regarding breastfeedReceived: 6 January 2022 Revised: 15 February 2022 Accepted: 15 February 2022 Correspondence to: Ellen Ai-Rhan Kim, MD Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Tel: +82-2-3010-3390 Fax: +82-2-3010-6978 E-mail: arkim@amc.seoul.kr A Multi-Center Educational Research Regarding Breastfeeding for Pediatrics Residents in Korea Yong-Sung Choi, MD,PhD1, Sung-Hoon Chung, MD, PhD2, Eun Sun Kim, MD, PhD3, Eun Hee Lee, MD4, Euiseok Jung, MD5, So Yeon Lee, MD, PhD5, Wooryoung Lee, MD6, Hye Sun Yoon, MD, PhD7, Yong Joo Kim, MD, PhD8, Ji Kyoung Park, MD, PhD9, Son Moon Shin, MD, PhD9, and Ellen Ai-Rhan Kim, MD, PhD5 1Department of Pediatrics, Kyung Hee University Hospital, Seoul, Korea 2Department of Pediatrics, Kyung Hee University Hospital at Gangdong, Seoul, Korea 3Department of Pediatrics, Kangwon National University Hospital, Chuncheon, Korea 4Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea 5Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 6Department of Pediatrics, Soonchunhyang University Seoul Hospital, Seoul, Korea 7Department of Pediatrics, Nowon Eulji Medical Center, Eulji University, Seoul, Korea 8Department of Pediatrics, Hanyang University Seoul Hospital, Seoul, Korea 9Department of Pediatrics, Inje University Busan Paik Hospital, Busan, Korea Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 pISSN 2287-9412 . eISSN 2287-9803 Copyright(c) 2022 By Korean Society of Neonatology This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Original Article 29 Neonatal Med 2022 February;29(1):28-35 https://doi.org/10.5385/nm.2022.29.1.28 ing in Korea.

기관지폐 이형성증의 임상 양상: 다기관 연구

성기혜 ( Ki Hye Sung ),김민희 ( Min Hee Kim ),김은령 ( Eun Ryoung Kim ),심재원 ( Jae Won Shim ),이정주 ( Jung Ju Lee ),임재우 ( Jae Woo Im ),진현승 ( Hyun Seung Jin ) 대한주산의학회 2009 Perinatology Vol.20 No.3

목적: 최근 극소 저출생 체중아의 생존율의 개선으로 기관지폐 이형성증(bronchopulmonary dysplasia, BPD)이 늘고 있다. 다기관 연구에 의해 전국적인 BPD의 역학, 임상 양상과 각 병원 간의 차이를 조사하여 향후 우리나라의 BPD 감소와 중증도를 줄이는 것을 목적으로 본 연구를 시행하였다. 방법: 2005년 6월부터 2007년 5월까지 건국대학교병원, 영등포 성애병원, 강북삼성병원, 중앙대학교병원, 건양대학교병원, 강릉아산병원의 신생아 집중 치료실에 입원하였던 신생아 4,476명을 대상으로 하였다. BPD의 진단 기준은 비전형적인 BPD를 포함하여 병인적인 분류를 하고 있는 Ogawa 등의 분류법을 이용하여 신생아 호흡 곤란 증후군(respiratory distress syndrome, RDS)과 전형적 또는 미만성 혼탁의 방사선 소견, 산전 감염의 유무에 따라 6가지 type으로 분류하였다. 또한 전체 신생아의 출생체중 분포와 생존율, 각 출생체중 군별 BPD의 발생률, 병태 비율, 사망률 등을 조사하고, 이 후 재택 산소요법 시행 여부와 미숙아 망막증, 괴사성 장염 등의 합병증 여부를 조사하였다. 결과: 생후 28일째 산소 치료가 필요한 신생아는 89명이었고, 이 중 Ogawa 분류법에 의한 BPD 환아는 70명(1.6%)이었으며, 특히 1,500 g 미만의 환아 237명 중 60명(25.3%)이었다. 생후 28일 이상 생존율은 98.7%이고, 사망 예는 없었으며 평균 재원 기간은 97.8±51.2일(43~405일)이었다. BPD는 900~999 g, 1,000~1,249 g의 체중 군에서 발생률이 각각 15명(21.4%)으로 가장 높았으며, 교정 36주 이후에도 산소투여가 필요한 중증 BPD의 경우 900~999 g의 체중 군에서 7명(23.3%)로 가장 높았다. Ogawa 분류법으로 BPD의 각 병태 비율로는 RDS 이후에 나타나는 I, II형이 각각 전체의 17예(24.3%), 44예(62.9%)로 대다수를 차지하였다. 이외에도 III`형은 2예(2.9%), IV형은 2예(2.9%), V형은 5예(7.1%)이었고, III형, VI형은 없었다. 재택 산소요법은 8예에서 시행되어 전체의 11.4%였으며, 이 중 BPD I형이 7예로 87.5%를 차지하였다. 미숙아 망막증은 35명(50.0%)에서 발생하였으며, 700 g 이하 신생아에서 9예(26.5%)로 가장 많았다. 또한 괴사성 장염은 3명(4.3%)이었다. 결론: 본 연구는 국내에서 처음으로 진행된 BPD의 전국적인 다기관 역학 조사로, 대상 신생아의 Ogawa 분류에 의한 BPD 유병률은 1.6% 이었고 1,500 g 미만 신생아의 25.3%이었으며, 전체 신생아의 BPD 70명 중 Ogawa 분류의 I, II형이 각각 24.3%, 62.9%로 대다수를 차지하였다. Purpose: As the neonatal intensive care advanced, the incidence of neonatal bronchopulmonary dysplasia (BPD) has increased. We conducted a multi-center investigation of the prevalence of BPD in six hospitals to investigate the epidemiology of BPD in Korea. Methods: Retrospective reviews ware performed for survival rate, prevalence of BPD of total 4,476 newborn infants who were admitted to neonatal intensive care unit in Konkuk university hospital, Sung-Ae General hospital, Kangbuk Samsung hospital, Chung-Ang university hospital, Konyang university hospital, and Gangneung Asan hospital between June, 2005 and May, 2007. By Ogawa, BPD was defined as oxygen dependency at 28 days after birth, with respiratory distress symptoms and the change of chest x-ray finding, and classified as 6 subtypes. Classic BPD was defined as oxygen dependency at 36 weeks of postmenstrual age. Results: Survival rate at 28 day after birth was 98.7%. BPD infants by Ogawa classification were 70 (1.6% of overall newborn infants), classic BPD infants were 30 (0.7%). Especially, among 237 preterm infants with birth weight less than 1,500 gram who survived to 28 days of life, 60 (25.3%) had BPD by Ogawa classification and 23 (9.7%) had classic BPD. In Ogawa classification, infants with RDS as type I and II, were 17 infants (24.3%) and 44 infants (62.9%). Home oxygen therapy was performed 8 infants (11.4%). Prevalence of retinopathy of prematurity was 35 infants (50.0%), necrotizing enterocolitis was 3 infants (4.3%), and intraventricular hemorrhage was 6 infants (8.6%). Conclusion: Prevalence of BPD infants was 1.6% of overall newborn, 25.3% of preterm infants with birth weight less than 1,500 gram. Among 70 BPD infants, BPD by Ogawa classification with history of RDS as type I and II were 24.3%, 62.9% as the majority of BPD. This study would be the first report of epidemiology of Korean BPD infants by multi-center study.

Cilostazol Inhibits Vascular Smooth Muscle Cell Proliferation and Reactive Oxygen Species Production through Activation of AMP-activated Protein Kinase Induced by Heme Oxygenase-1

Jung Eun Kim,Jin Young Sung,Chang-Hoon Woo,Young Jin Kang,Kwang Youn Lee,Hee Sun Kim,Woo Hyung Kwun,Hyoung Chul Choi 대한생리학회-대한약리학회 2011 The Korean Journal of Physiology & Pharmacology Vol.15 No.5

Cilostazol is a selective inhibitor of phosphodiesterase 3 that increases intracellular cAMP levels and activates protein kinase A, thereby inhibiting vascular smooth muscle cell (VSMC) proliferation. We investigated whether AMP-activated protein kinase (AMPK) activation induced by heme oxygenase-1 (HO-1) is a mediator of the beneficial effects of cilostazol and whether cilostazol may prevent cell proliferation and reactive oxygen species (ROS) production by activating AMPK in VSMC. In the present study, we investigated VSMC with various concentrations of cilostazol. Treatment with cilostazol increased HO-1 expression and phosphorylation of AMPK in a dose- and time-dependent manner. Cilostazol also significantly decreased platelet-derived growth factor (PDGF)-induced VSMC proliferation and ROS production by activating AMPK induced by HO-1. Pharmacological and genetic inhibition of HO-1 and AMPK blocked the cilostazol-induced inhibition of cell proliferation and ROS production.These data suggest that cilostazol-induced HO-1 expression and AMPK activation might attenuate PDGF-induced VSMC proliferation and ROS production.

Increase in Insulin Secretion Induced by Panax ginseng Berry Extracts Contributes to the Amelioration of Hyperglycemia in Streptozotocininduced Diabetic Mice

Eun-Young Park,Ha-Jung Kim,Yong-Kyoung Kim,Sang-Un Park,Jae-Eul Choi,Ji-Young Cha,Hee-Sook Jun 고려인삼학회 2012 Journal of Ginseng Research Vol.36 No.2

Panax ginseng has long been used as a traditional herbal medicine. More recently, it has received attention for its anti-diabetic and anti-obesity effects in humans and in animal models of type 2 diabetes. In the present study, we tested the hypoglycemic effects of ginseng berry extract in beta-cell-defi cient mice and investigated the mechanisms involved. Red (ripe) and green (unripe) berry extracts were prepared and administered orally (100 or 200 ㎎/㎏ body weight) to streptozotocin-induced diabetic mice daily for 10 wk. The body weight was measured daily, and the nonfasting blood glucose levels were measured after 5 and 10 wk after administration. Glucose tolerance tests were performed, and the serum insulin levels were measured. The proliferation of betacells was measured in vitro. The administration of red or green ginseng berry extract signifi cantly reduced the blood glucose levels and improved the glucose tolerance in beta-cell defi cient mice, with the higher doses resulting in better effects. Glucose-stimulated insulin secretion was signifi cantly increased in berry extract-treated mice compared with streptozotocin-induced diabetic control mice. Treatment with ginseng berry extract increased beta-cell proliferation in vitro. Both red berry and green berry extracts improved glycemic control in streptozotocin-induced diabetic mice and increased insulin secretion, possibly due to increased betacell proliferation. These results suggest that ginseng berry extracts might have benefi cial effects on beta-cell regeneration.

Prevalence And Risk Factors For Atrial Fibrillation in the Elderly Korean Population

( Jung Nam Eun ),( Jeong Gwan Cho ),( Sung Soo Kim ),( Hyung Wook Park ),( Ki Hong Lee ),( Nam Sik Yoon ),( Yong Woon Yun ),( Min Ho Shin ),( Jun Ho Shin ) 대한내과학회 2015 대한내과학회 추계학술대회 Vol.2015 No.1

Background: Atrial fibrillation (AF) is the most common arrhythmia in elderly persons and associated with increased risk for thromboembolism and stroke. However, prevalence and risk factors for AF have not been known well in Korean population. Also, electrocardiographic (ECG) screening for AF in general population showed inconsistent results for reducing thromboembolism. We aimed to evaluate prevalence, risk factors for AF and benefit for ECG screening the elderly single cohort study. Methods: Consecutive 1,483 participants over 60 yr-old underwent ECG screening at the Bitgoel senior health town from March 2014.This cohort study include questionnaire for quality of life, physical examination, and further laboratory and echocardiographic findings in patients with AF. Multivariate analysis was performed to evaluate independent risk factors for AF. Benefit for ECG screening will be evaluated after 5-year completion of participants enrollment. Results: Prevalence of AF was 3.1% and increased with stepwise manner according to age group (1.0% vs. 3.3% vs. 7.2%, p<0.001). Patients with AF was elder, and more likely to be male, smoker and obese. Also, they had higher prevalence of diabetes mellitus and heart failure compared with patients without AF. Nearly half patients with AF (43.4 %) were newly detected via ECG screening. CHA2DS2-VASc and HAS-BLED score were not different between the patients with newly detected AF and already diagnosed AF. Anticoagulation was done 12 (26%) patients with CHA2DS2-VASc ≥2. Multivariable analysis demonstrated that AF was associated with increasing age (adjusted odds ratio [OR] 1.10, 95% confidence interval [CI] 1.04-1.16, p<0.001), male gender (adjusted OR 4.92, 95% CI 1.75-13.82, >p=0.002), obesity (BMI >25, adjusted OR 2.25, 95% CI 1.19-4.24, p=0.012) and heart failure (adjusted OR 7.28, 95% CI 1.17-45.24, p=0.033). Conclusions: The prevalence of AF was 3.1% in the elderly, which was much lower than western countries. Most of them were under-detected and under-treated in terms of anticoagulation. Further studies will determine that routine ECG screening might reduce the risk for thromboembolism in patients with AF.

Evaluation of a novel tyrosinase inhibitor, (Z)-3-(3-bromo-4-hydroxybenzylidene) thiochroman-4-one (MHY1498) in vitro and in silico

( Eun Jin Bang ),( Sang Gyun Noh ),( Su Gyeong Ha ),( Hee Jin Jung ),( Dae Hyun Kim ),( Dongwan Kang ),( Sanggwon Lee ),( Chaeun Park ),( Hyung Ryong Moon ),( Hae Young Chung ) 한국장기요양학회 2018 한국장기요양학회 추계학술대회자료집 Vol.2018 No.-

Tyrosinase is a key enzyme that catalyzes the initial rate-limiting steps of melanin synthesis. Excessive melanogenesis and hyperpigmentation is the major cause of serious skin disorders that include melasma, senile lentigines, age spots, freckles and more. In order to find effective and safe tyrosinase inhibitors, we rationally designed and synthesized a novel compound (Z)-3-(3-bromo - 4 - h y d r o x y b e n z y l i d e n e) t h i o c h r o m a n - 4 - one (MHY1498) and investigated its tyrosinase inhibitory activity by in silico molecular docking simulation and in vitro experiments. The novel chemical structure of MHY1498 was synthesized as a hybrid structure of previously reported potent tyrosinase inhibitors, (Z)-5-(substituted benzylidene) thiazolidine-2,4-diones and 2-(substituted phenyl) benzo[d]thiazoles as was confirmed in vitro and in vivo. MHY1498 showed potent inhibitory effects on mushroom tyrosinase with significantly less IC50 value of 4.1±0.6 μM, whereas positive control compound Kojic acid was of 22.0±4.7 μM. In silico multi-docking simulation indicated that MHY1498 had greater affinity (-6.6 kcal/mol) to the active enzymatic site of mushroom tyrosinase and mechanistic kinetic study showed that it inhibited competitively. Furthermore, in B16F10 melanoma cells stimulated with α-melanocyte stimulating hormone, MHY1498 inhibited melanin contents and tyrosinase activity. In conclusion, our data demonstrate that MHY1498, a synthesized novel compound, effectively inhibits tyrosinase activity and may be used as a modulating compound for anti-melanogenic agent.

Frequent Occurrence of SARS-CoV-2 Transmission among Non-close Contacts Exposed to COVID-19 Patients

Jung Jiwon,Lee Jungmin,Kim Eunju,Namgung Songhee,Kim Younjin,Yun Mina,Lim Young-Ju,Kim Eun Ok,Bae Seongman,Kim Mi-Na,Lee Sun-Mi,Park Man-Seong,Kim Sung-Han 대한의학회 2021 Journal of Korean medical science Vol.36 No.33

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission among non-close contacts is not infrequent. We evaluated the proportion and circumstances of individuals to whom SARS-CoV-2 was transmitted without close contact with the index patient in a nosocomial outbreak in a tertiary care hospital in Korea. From March 2020 to March 2021, there were 36 secondary cases from 14 SARS-CoV-2 infected individuals. Of the 36 secondary cases, 26 (72%) had been classified as close contact and the remaining 10 (28%) were classified as non-close contact. Of the 10 non-close contact, 4 had short conversations with both individuals masked, 4 shared a space without any conversation with both masked, and the remaining 2 entered the space after the index had left. At least one quarter of SARSCoV-2 transmissions occurred among non-close contacts. The definition of close contact for SARS-CoV-2 exposure based on the mode of droplet transmission should be revised to reflect the airborne nature of SARS-CoV-2 transmission.

Clinical Factors Associated with Brachial-Ankle Pulse Wave Velocity in Patients on Maintenance Hemodialysis

( Eun Young Kim ),( Joo Hark Yi ),( Sang Woong Han ),( Jin Ho Shin ),( Jae Ung Lee ),( Soon Gil Kim ),( Ho Jung Kim ) 대한전해질학회 2008 Electrolytes & Blood Pressure Vol.6 No.2

Pulse wave velocity (PWV) is a main parameter for arterial stiffness. In patients with end-stage renal disease (ESRD), PWV is known to be associated with increased mortality. But factors related to the increased PWV in ESRD patients are not well defined. In addition, the carotid-femoral PWV (cfPWV) measurement, which traditionally has been used to evaluate arterial stiffness, has low reproducibility. Recently, brachial-ankle PWV (baPWV) measurement, which can be performed more easily than cfPWV measurement, has become available as a means of measuring PWV. The aim of this study is to investigate the clinical factors associated with increased baPWV in ESRD patients. BaPWV was examined for 65 ESRD patients on maintenance hemodialysis during the period between the 7th to the 11th of February in 2005 using VP-1000. The clinical factors included age, sex, smoking history, blood pressure, diabetes, body mass index, interdialytic weight gain, duration of dialysis, lipid profile, uric acid, albumin, creatinine, C-reactive protein, calcium, phosphate, intact parathyroid hormone, and hematocrit were analyzed regarding associations (or to determine associations) with baPWV. The median age was 53.8±12.0, 31 males and 34 females. BaPWV was 18.9±5.2 m/s and there was no significant difference between gender (18.1±4.4 m/s vs 19.4±5.9 m/s, p=NS). In multiple regression models, age, predialysis systolic blood pressure, and diabetes were independent variables. In conclusion, age, systolic blood pressure, and diabetes were correlated with baPWV in ESRD patients. Thus baPWV measured by simple, noninvasive methods may become available for screening high risk groups in ESRD patients, although further longitudinal studies are necessary.

Sustained K<SUP>+</SUP> Outward Currents are Sensitive to Intracellular Heteropodatoxin2 in CA1 Neurons of Organotypic Cultured Hippocampi of Rats

Sung-Cherl Jung,Su-Yong Eun 대한생리학회-대한약리학회 2012 The Korean Journal of Physiology & Pharmacology Vol.15 No.5

Blocking or regulating K⁺ channels is important for investigating neuronal functions in mammalian brains, because voltage-dependent K⁺ channels (Kv channels) play roles to regulate membrane excitabilities for synaptic and somatic processings in neurons. Although a number of toxins and chemicals are useful to change gating properties of Kv channels, specific effects of each toxin on a particular Kv subunit have not been sufficiently demonstrated in neurons yet. In this study, we tested electrophysiologically if heteropodatoxin2 (HpTX₂), known as one of Kv4-specific toxins, might be effective on various K⁺ outward currents in CA1 neurons of organotypic hippocampal slices of rats. Using a nucleated-patch technique and a pre-pulse protocol in voltage-clamp mode, total K⁺ outward currents recorded in the soma of CA1 neurons were separated into two components, transient and sustained currents. The extracellular application of HpTX₂ weakly but significantly reduced transient currents. However, when HpTX₂ was added to internal solution, the significant reduction of amplitudes were observed in sustained currents but not in transient currents. This indicates the non-specificity of HpTX₂ effects on Kv4 family. Compared with the effect of cytosolic 4-AP to block transient currents, it is possible that cytosolic HpTX₂ is pharmacologically specific to sustained currents in CA1 neurons. These results suggest that distinctive actions of HpTX₂ inside and outside of neurons are very efficient to selectively reduce specific K⁺ outward currents.