• 제목/요약/키워드: Juvenile rat

검색결과 11건 처리시간 0.024초

발생중인 흰쥐 망막의 분화 및 Acetylcholinesterase 활성에 관한 연구 (A Study on the Differentiation and Acetylcholinesterase Activity of the Developing Rat Retina)

  • 김완종;최준섭
    • Applied Microscopy
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    • 제27권2호
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    • pp.131-144
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    • 1997
  • The present study was carried out to investigate the processes of the ultrastructural differentiation and the acetylcholinesterase (AChE) activities of the developing rat retina. The results are as follows. The retina of fetal rat on the 13th day of gestation showed the early stage of differentiation. Briefly, there appeared dividing chromosomes, the plentiful free ribosomes, and the high ratio of nucleus to cytoplasm. The reaction products by AChE were localized at the membrane of endoplasmic reticulum and on the outer membrane of nucleus. Ultrastructures and AChE activities in the retina of the fetal rats on the 18th day of gestation were similar to those of the prior stages, except the appearence of rough endoplasmic reticulum and Golgi apparatus. According to the ultrastructural observations, the rat retina was still in immature state at birth, but the pigment epithelial cells were fully differentiated, e. g. the increase of melanin granules, the development of mitochondria and Golgi apparatus. The AChE activity was weekly detected. The differentiated retinal layers and the outer segment of photoreceptor cells were observed on the 7th postnatal day. And the pigment epithelium appeared to be fully differentiated. On the 14th postnatal day, rat retina were completely differentiated. In other words, the rat retina was characterized by the prominent outer segments, phagocytosed residues in the pigment epithelium, and the localization of reaction products by AChE in the synapses. In conclusion, the differentiation of rat retina is charaterized by the changes of cell shape, the increase of retinal layers, and the alterations of AChE activities. It seems that rat retina is to be functional from 2 weeks of birth onward, coinciding with the eye opening of the juvenile rats.

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폐흡충(Paragonimus westermani) 감염시의 세포 면역학적 장어 기전 (Antibody-dependent rat macrophage-mediated damage Into the excysted metacercariae of Paragonimus westeymani in vitro)

  • 정평림;장재경;소진천
    • Parasites, Hosts and Diseases
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    • 제29권1호
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    • pp.43-54
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    • 1991
  • 폐홉충(Paragonimus westermani) 초기 감염시의 숙주 면역 기전을 알아보기 위하여 폐흡충 피낭유충을 백서에 감염시켜 주별(주별)로 항혈청을 분리하고 등일 백서에서 복강 대식세포(homologous rat peritoneal macrophage)를 얻은 다음, 이들과 폐흡충 탈낭유충 및 숙주 조직 이행중인 유약충으로 effector system을 조작하여 폐흡충 유충에 대한 항체 의존성 대식세포 공격기전을 관찰하였다. 백서 복강 대식세포는 항혈청 출현 시에만 폐흡충 탈낭유충에 대한 세포부착 반응(cell adherence reaction)을 보였고 이 반응에는 보체가 관여하지 않았다. 폐흡충 감염 1주에서 8주까지의 백서 항혈청 중 2주째에 분리한 항쳔청 실험군에서 100%의 세포부착 반응을 나타내었고 사멸된 충체를 관찰할 수 있었으며, 세포부착 반응은 탈낭 유충기에서만 나타나는 반면 조직이행 유약충에서는 전혀 그 반응을 인정할 수 얼어 폐흡충 감염에 따른 항체의존성 숙주 세포 매개독성(antibodydependent cell·mediated cytotoxicity)은 발육단계 별 특이성을 보였다. 한편, 대식세포의 공격에 의하여 사멸된 폐흡충 탈낭유충의 형태학적 특징은 대식세포와 유충 사이에 형성되는 fuzzy material, tegumental syncytium 내의 미세구조의 변성 및 syncytium과 근육층을 연결하는 tubular tunnel의 형성 등이었다.

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Bile duct changes in rats reinfected with Clonorchis sinensis

  • Choi, Dong-Il;Hong, Sung-Tae;Li, Shun-Yu;Chung, Byung-Suk;Lim, Jae-Hoon;Lee, Soon-Hyung
    • Parasites, Hosts and Diseases
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    • 제42권1호
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    • pp.7-17
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    • 2004
  • This study describes an evaluation of the sonographic, cholangiographic, pathological, and immunological findings, and the protective effect shown by rats reinfected with Clonorchis sinensis. Eight experimental rat groups were, namely, a normal control, a primary infection control, a reinfection I (reinfection 7 week after treatment following 3-week infection), a reinfection II (reinfection 2 week after treatment following 8-week infection), a reinfection III (exploration of the intrahepatic bile ducts 1 week after reinfection 4 week after treatment following 4-week infection), a superinfection, a secondary infection control, and an infection following immunization group. Sonographic and cholangiographic findings showed moderate or marked dilatation of the bile duct confluence in the primary infection control, reinfection II, and secondary infection control groups. Juvenile worms survived in the intrahepatic bile ducts 1 week after reinfection following treatment in the reinfection III group. It was concluded that reinfecting juvenile worms found during the first week following reinfection failed to survive or grow further. Anatomical, pathophysiological, or immunological changes may induce protection from reinfection in rats.

Effects of Controlled Photoperiod on Body Development in Growing Juvenile Rats

  • Lee, Seung-Hoon;Lee, Han-Ki;Shin, Jin-Hee;Hong, Yun-Kyung;Lee, Sang-Kil;Lee, Sang-Un;Suzuki, Takao;Kang, Tae-Young;Hong, Yong-Geun
    • Reproductive and Developmental Biology
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    • 제34권2호
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    • pp.89-94
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    • 2010
  • Melatonin is induced by light information through the retina and leads to growth factor activation. Thus, we investigated the effects of melatonin by controlling the photoperiod of growing young rats. Male Sprague-Dawley rats (n=6; 4 weeks old) were divided into two experimental groups: the L/D group (normal photoperiod; light/dark: 12/12 h; lights on at 9:00 a.m.) and the L/L group (light/light: 24 h). Rat body weight and food consumption were measured daily for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of ketamine (50 mg/kg) and xylazine (10 mg/kg) and sacrificed. Tissue was then collected for RNA isolation (from brain, heart, liver, kidney, adrenal gland, testis, tibia, hind limb muscles). Also, serum was isolated from blood using a centrifugal separation. The L/L group had significantly lower body weight than the L/D group from 4 to 6 weeks (p<0.05). The L/D group had increased tissue mass, compared with the L/L group, but the difference was not statistically significant. The L/D group had a significantly higher melatonin concentration than the L/L group between the hours of midnight and 2:00 a.m (p<0.01). These results indicate that photoperiod length may affect the secretion of melatonin from the pineal gland. Also, the reduction of nocturnal melatonin secretion may retard the development of growing young rats. In future studies, we plan to compare exogenous melatonin administration with endogenous melatonin concentration induced by photoperiod control. Moreover, we will confirm whether the effects seen in pathological animal models can be reversed by controlling the photoperiod.

일 지역 중·고등학생의 흡연실태 (A Study on the Actual Conditions of Smoking in Middle and High School Students in One Region)

  • 김현옥
    • 한국학교보건학회지
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    • 제12권1호
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    • pp.149-167
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    • 1999
  • To investigate the actual conditions of smoking in middle and high school students in Chinan County, I used a sturctured questionnaire for 1,579 students attending twelve middle-high schools from December 1, 1998 to December 20, 1998. I collected and data correlated the using an $SPSS-PC^+$ 1. The smoking rate of middle-high schoo1 students in Chinan County was 17.9%, relatively high. This smoking rate was different according to the gender, grade, religion, and economic situation. In mals, high school students, non-religious, students low income family students, the smoking rate was higher. The smoking rate of high school students was almost the same as the smoking rate of adults, generally higher than that of foreign teenagers. Because the smoking rat of studinets in the third grade of middle school and in the first grade of high School was six times higher, increased education should be conducted during this time in an attempt to curb the sudden increase of the smoking rate. The smoking rate of girl students was 5.0%; this has increased mor than three times from ten years ago. Consequently, counter measures should be taken against the smoking of female students as well as juvenile smoking in general. In addition, the smoking rate of middle-high school students showed interesting differences when correnated with enviornmental factors. Students with low grades, who are not satisfied with school life, who don't have both parents, who have uncaring parents who nare too strict or too arbitary, who have smoking parents, or who have experienced smoking commonly smoked. Therefore, to lower the smoking rate we should improve the school environment, improve a student's interest in school life. And parents or siblings should lead by example and quit smoking at home. Schools should educate students more effectively concerning the harmful effects of smoking and create an accurate understanding of its dancers. From the beginning, we should teach students never ever to touch cigaretts. 2. The surve discovered that most students started out of curiosity, or solicitantion from friends or elders at middle school, and had been smoking one to five cigarettes for more than a year. They obtained cigarettes at stores and most of them have friends who smoke. As a result anti-smoking education should be conducted at elementary schools prior to middle school. More than 95% of the teenagers who smoke had friends who smote and smoked out of curiosity or the recommendation of elders. Thus, we must focus on teenagers who smoke in group, rather than individually. Fuyrthermore, the strict application of the regulation of tobacco sales as well as tobacco cooperation from retailers are needed. While students did not show any mood or academic achievement difference after beginning smoking, 58.1% of the students a health situdation that was worse. Juvenile smoking is more harmful to the juvenile than adult smoking is to the adult. This should be focused on in an anti-smoking campaign. 3. Students who smoke hada more positive attitude toward smoking than students who don't smoke. Students who smoke had a tendency to have a nuetral position and are not concerned about smoking compared to non-smoking students. The survey showed that the great number of students had a nuetral position. Because this nuetrality may increase Juvenile smoking, education that provides an exact understanding of smoking should be performed to build the correct attidude toward smoking. 4. Middle school students smoke when angry, gloomy, anxious, a lone and when they have some problems to solve, on when they feel inconveniened in other wores, they smoke to reliver stress. They also smok due to addiction. Because smoking is not a praetical method to relieve stress, a program which helps to acquire positive relief stress should be provided to help reduce smoking. 5. About 65% of students who smoke want to quit smoking because of health problem, 78% of them have tried mor than once to quit but failed due to weak will power and peer pressure from friends who smoke. Juvenile smoking is group, oriented. Thus, the program that advances less smoking will be the one that focuseds on groups. 6. As for advice to students who want to quit smoking, "persuasion" was used most commonly, followed by a "presentation on how to quit smoking". Another method were severe punishment. About 70% of the students wanted the anti-smoking guide at school. 7. Most students (73.5%) had a position that more anti-smoking education at school is needed. Obriously, then, anti-smoking education at middle-high schools should be reinfoced. Although the education which explains the harmful influence of tobacco is known as an efficient way prevent smoking; it does not influence students who already smoke. Therefore, for students who smoke, multi-dimensional approaches must be attempted that include physical training, phychokogical approache, consultation and discussion, medical chek-ups, audio-visual education technigues, and professonal instructors, in addition, because smoking students have more negative on lukewarm attitude to anti-smoking education anti-smoking education should be conducted through a communicative style by dedicated teachers who care about students. In order to increase the effectiveness of this program.

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MSG의 반복투여가 어린랫드의 인지능력과 기억력에 미치는 영향 (Effect of Repeated MSG Administration on Cognitive Ability and Anxiety of Juvenile Rats)

  • 이해님;추강식;신성아;박정준;이세근;김세운;김현선;이송희;임정민;김형진;박영석;김상기;박병권;김병수;정지윤
    • 한국식품위생안전성학회지
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    • 제30권1호
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    • pp.120-125
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    • 2015
  • 본 연구는 Sprague-Dawley 계통의 4주령 랫드에서 MSG의 반복경구투여 독성평가와 행동실험을 통해 어린랫드의 인지능력과 불안감에 미치는 영향을 평가하기 위해서 시행하였다. 시험군은 MSG 대신 distilled water를 투여한 대조군(Control, n = 4), MSG를 3 g/kg을 투여한 군(Low, n = 4), MSG를 5 g/kg을 투여한 군(High, n = 4)으로 나누어 4주 동안 주5회 경구투여를 하였다. MSG의 안정성을 확인하기 위해 다음과 같은 관찰 및 검사를 하였다. 검사항목으로는 체중의 변화, 임상증상, 행동실험인 T-maze, Elevated-plus-maze와 혈액학적 검사, 혈청생화학적 검사, 병리조직학적 검사를 관찰한 결과 모든 투여군 및 대조군에서 특이할 만한 임상증상과 체중변화는 관찰되지 않았으며, 폐사 및 빈사 동물은 시험 전 기간을 통하여 발견되지 않았다. 행동실험인 T-maze 결과 MSG 고용량 투여군에서 움직이는 횟수가 감소하다 증가하는 양상을 보였고, Elevated-plus-maze 실험에서는 MSG 고용량 투여군의 Open arm의 출입빈도가 증가하는 등 유의적인 변화가 나타났다. 혈액학적 검사 및 혈청생화학적 검사에서는 대조군과 비교 시 유의적인 변화가 관찰되었지만 그 수치가 정상범위 안에 포함되기 때문에 이상을 나타내지 않았다. 병리조직검사 또한 약간의 염증발생 소견이 나왔지만 정상범위 안에 포함되기 때문에 이상을 나타내지 않았다고 판단했다. 따라서, 어린랫드를 이용한 MSG의 반복투여 독성시험 결과 특이할만한 신체적인 변화는 나타나지 않았으나 고용량의 MSG 투여는 어린랫드에서 인지능력의 저하 및 행동의 불안을 유발할 가능성이 있다고 사료된다.

이전고환극구흡충 유약충 및 성충의 표피 미세구조 (Tegumental ultrastructure of juvenile and adult Echinostoma cinetorchis)

  • 이순형;전호승
    • Parasites, Hosts and Diseases
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    • 제30권2호
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    • pp.65-74
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    • 1992
  • 이전고환극구흡충(Echinostomn cinetorchis) 유약충 및 성충의 표피 미세구조를 주사전자현미경으로 관찰하였다. 실험적으로 미라시디움을 감염시킨 또아리물달팽이 (Hippeutis cantari)에서 피낭유충을 얻어 횐쥐에 경구 감염시킨 다음 3일(유약충) 및 16일(성충)에 각각 충체를 회수하였다. 회수한 충체를 2.5% glutaraldehyde 용액에 고정하고 탈수, 댕동 건조 및 순금 표면처리 후 주사전자현미경으로 관찰하였다 감염 3일의 유약충은 충체가 길쭉하며 복측으로 만곡되어 있었고 복흡반이 충체 전방 215 지점에 위치하였다 두관에는 모두 37∼38개의 두극이 중단없이 지그재그형으로 배열되어 있었다. 구흡반 및 복흡반의 구순에는 각각 8개 및 5개의 제 R형 감각유두가 일정한 간격으로 배열되어 있었고, 피극들 사이에 제 해형 감각유두가 드물게 관찰되었다. 복홉반 전방의 피극들은 혀 또는 삽 모양, 후방의 피극들은 송곳 모양이었고, 후방으로 갈수록 밀도가 낮았다. 충체 배면의 피극들은 복면의 것들과 비슷하였으나, 후방 113 지점부터는 피극이 분포하지 않았다. 감염 16일의 성충은 나뭇잎 모양이며, 구흡반과 복홉반이 매우 근접하여 있었다. 두관, 구흡반 및 복흡반 등 피극이 분포하지 않는 곳에는 제 E형 및 제 여형 감각유두가 분포하였고, 피극이 분포하는 표피에는 제 I형 감각유두가 1∼4개씩 군(group)을 형성하고 있었다. 복흡반 전방에는 비늘 모양의 피극들이 밀생해 있었고, 후방으로 갈수록 감소하였다. 배면 전방에는 피극이 드물게 분포 하나 후방에서는 피극이 관찰되지 않았다. 이상의 결과로 볼 때, 이전고환극구흡충은 두극의 수, 배열, 피극의 형태, 분포, 감각유두의 종류, 분포 등에 있어서 다른 극구흡충류와 다른 점이 많으며, 유약충에서 성충으로 발육함에 따라 피극과 원형질 돌기의 분화는 물론 감각유두의 종류, 분 포 등이 달라짐을 알 수 있었다. 항체는 43 kDa, N( 137 항체는 29 kDa에 해당되는 분획에서 항원항체반응을 나타내었다. 이상의 성적을 종합하면 N. fowleri에 대한 7종류의 IgG., IgG3 및 IgA 단세포군 항체를 생산하였다. 그중 Nf 256 항체를 제외한 6 종류는 N. fowleri이 세포막 성분중 28 kDa-43 kDa의 항원과 반응하는 특이한 항체임을 관찰할 수 있었다. 또한 이 단세포를 항체들은 영양형을 응집시키며, 시험관 내에서의 증식을 억제시키고 CHO 세포에 대한 N. fowleri의 세포 독성을 저하시키는 성질을 가지고 있음을 알 수 있었다.들 중에서 최적의 기종점 통행표를 발견하는 것이다. 따라서 교통망에서 통행자의 여행 경로 배정을 가장 잘 반영할 수 있는 현실적인(Realistic) 교통망 통행 배정 모형(Net-work Traffic Assignment Model)의 선택은 중요한 요소가 되며 특히 교통망에 교통체증(Traffic Conges-tion)이 심할 경우 교통망 통행자 평형조건(Network Traffic Equilibrium Condition)을 고려하기 위한 특별한 처리가 요구되어진다. 본 연구는 Whllumsen(Hall, Van Vliet and Willumsen, 1980)에 의하여 개발된 ME2(Maximum Entropy Matrix Estimation)기법에서 반복식 추정방법(Sequential Estimation Method)을 사용할 경우 Wardrop의 평형조건을 만족하는 기종점 통행표를 구할 수 없다는 단점을 극복하기 위한 방안으로서 엔트로피 극대화문제와 교통망 평형 조건(Entropy Maximisation and Network Equilibrium Condition)의 두 문제를 동시에 해결할 수 있는 새로운 수식모형과 이를 풀기 위한 알고리즘(Simultaneous Solution Algorithm)을 제의하였다. 제의된 수식모형과

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Effect of Anionic Alkali Mineral Complex Barodon$^{(R)}$ on Body Growth and Testicular Development in Rats

  • Chung, Y.C;Kim, C.K.;Kim, I.;Kim, K.S.;J.W. Ryu;S.E. Yeon;Lee, E.S.;Park, S.I.;K.S. Jeon
    • 한국동물번식학회:학술대회논문집
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    • 한국동물번식학회 2001년도 춘계학술발표대회
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    • pp.39-39
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    • 2001
  • Effects of Barodon$^{(R)}$ on body growth, histological changes in seminiferous tubules of testes and serum level of testosterone and FSH were examined in juvenile rats from 5 to 38 wks of age. All rats supplied feed and Barodon-added water(0, 0.1, 0.15, 0.3 and 1.0%) available ad libitum. DNA distribution of testicular cells from control rats obtained by flow cytometry was characterized by 4 peaks representing I : elongated, II round spermatids(1N), III: a variety of 2N cells and IV: 4N cells. Frequencies of 4 testicular cell types were calculated using cumulative DNA frequency distributions. Body growth from 18wk of age was significantly accelerated in rats supplied water with 0.15% Barodon compared to other groups. Testes weights tended to be greater in 0.15% Barodon-treated rats than in control, without significant difference. Diameter of seminiferous tubules advanced in 0.15-0.3% Barodon till 26 wk of age, but there was not significant different. Proportion of spermatids in seminiferous tubules was 48.4% at 6wk of age(round: 81.2% and elongated: 18.8% as proportion of total spermatids) and frequency of spermatids was higher in 0.3% Barodon group(57.1%) than in control(44.0%), but there was no significant difference. Serum testosterone of all groups significantly elevated at 18wk of age and level in 0.15% Barodon group was greatly higher than in others. Serum FSH at 10wks was greatly higher in 0.1-0.3% Barodon groups compared to control, but there were no significant differences. It is concluded that 0.15-0.3% Barodon treatment tended to induce precocious puberty in rats.

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가령에 따른 백서 악관절 원판의 형태 및 미세구조적 변화 (CHANGES IN THE SHAPE AND ULTRASTRUCTURE OF THE ARTICULAR DISC OF THE RAT MANDIBULAR JOINT WITH AGING)

  • 서혜경;경희문;성재현;배용철
    • 대한치과교정학회지
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    • 제24권2호
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    • pp.331-348
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    • 1994
  • The purpose of this study was to investigate changes in the shape and ultrastructure of the articular disc of the rat mandibular joint with aging. Mechanical stress applied to the articular disc changes during neonatal, suckling, juvenile, adult and senile stages. Mandibular joints of 6 groups of rats(1-, 7-, 17-, 27-, 55-day and over-1-year groups) were removed en bloc and processed for light and electro microscopic study. The changes in the shape of articular disc were examined by light microscope in each group. Structural and ultrastructural changes in the articular disc were examined by light and electron microscope in each group. The results were as follows : In the 1-day and 7-day groups, the articular disc was long and slender in shape and the articular disc was not fitted with the shape of the mandibular fossa and condyle. However' after that time, the anterior and posterior portions of the articular disc were more bulged and the middle portion was shorter and biconcave. Thus the articular disc was well fitted with the shape of the mandibular fossa and condyle. The cell density decreased with aging. In the l -day and 7-day groups, the Golgi apparatus, rough endoplasmic reticulum and free ribosome, which are involved in the synthesis of intracellular and extracellular matrix, were developed. In the 17-day, 27-day and 55-day groups, not only the cell organelles involved in the synthesis of the intracellular and extracellular matrix but also the cell organelles involved in the remodeling of the extracellular matrix(i.e., finger-like cell process, lysosome and mitochondria)were well developed. With advancing age, intracytoplasmic microfilaments were more accumulated and condroid cells increased. In the over-1-year group, the majority of cells of the articular disc were chondroid cells. The majority of cytoplasmic compartment were filled with intracytoplasmic microfilaments and cell organelles were not developed. Therefore, metabolic activities of the cell was markedly reduced and cells contained structures enduring mechanical stress, and cells which were in the process of degeneration were observed occasionally.

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Effects of Saccharin Intake on Hippocampal and Cortical Plasticity in Juvenile and Adolescent Rats

  • Park, Jong-Sil;Yoo, Sang-Bae;Kim, Jin-Young;Lee, Sung-Joong;Oh, Seog-Bae;Kim, Joong-Soo;Lee, Jong-Ho;Park, Kyung-Pyo;Jahng, Jeong-Won;Choi, Se-Young
    • The Korean Journal of Physiology and Pharmacology
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    • 제14권2호
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    • pp.113-118
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    • 2010
  • The sensory system is developed and optimized by experiences given in the early phase of life in association with other regions of the nervous system. To date, many studies have revealed that deprivation of specific sensory experiences can modify the structure and function of the central nervous system; however, the effects of sensory overload remains unclear. Here we studied the effect of overloading the taste sense in the early period of life on the synaptic plasticity of rat hippocampus and somatosensory cortex. We prepared male and female Sprague Dawley rats with ad libitum access to a 0.1% saccharin solution for 2 hrs per day for three weeks after weaning on postnatal day 22. Saccharin consumption was slightly increased in males compared with females; however, saccharin intake did not affect chow intake or weight gain either in male or in female rats. We examined the effect of saccharin-intake on long term potentiation (LTP) formation in hippocampal Schaffer collateral pathway and somatosensory cortex layer IV - II/III pathways in the 6-week old saccharin-fed rats. There was no significant difference in LTP formation in the hippocampus between the control group and saccharin-treated group in both male and female rats. Also in the somatosensory cortex, we did not see a significant difference in LTP among the groups. Therefore, we conclude that saccharin-intake during 3~6 weeks may not affect the development of physiological function of the cortical and hippocampal synapses in rats.