• 제목/요약/키워드: Newborn animal

검색결과 92건 처리시간 0.031초

Predicting Parturition Time through Ultrasonic Measurement of Posture Changing Rate in Crated Landrace Sows

  • Wang, J.S.;Wu, M.C.;Chang, H.L.;Young, M.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제20권5호
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    • pp.682-692
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    • 2007
  • This study presents an automatic system to predict parturition time in the crated sows. The system relies on ultrasonic transducers mounted from above along the length of the crate. Using a 40 kHz time of flight (TOF) single envelope wave, the momentary distances between the sensors are measured. Therefore, the local momentary height of the sow and the momentary posture, i.e. standing posture (SDP), kneeling posture (KP), sitting posture (STP) and lateral lying posture (LLP) are determined. Crated sows change their postures from standing to lying and vice versa which follows a characteristic pattern. As parturition approaches, sows exhibit uneasiness, restlessness and the stand up sequence (SUS, the posture transition from LLP to SDP) rate increases because of labor pains. In time series, the SUS rate demonstrates a peak and it happens approximately 0-12 h before parturition. In this paper, the basic parturition threshold value method (BPTVM) and the same hour method (SHM) are proposed for predicting parturition, both of which are based on the SUS rate. The BPTVM mainly detects the peak of the SUS rate. As the SUS rate exceeds the threshold value, the parturition becomes predictable. Moreover, the SHM calculates the difference in the SUS rates between a particular time of day and the corresponding time of the preceding day. Compared to the BPTVM, the SHM can eliminate the circadian rhythm of the SUS rate influenced by feeding behavior. Using the SHM the parturition can be approximately predicted within hours. In an attempt to define the threshold parameters of predicting parturition, a data set with 32 sows of the SUS rate are used to estimate assumable predicting probability. The results show the assumable probability of the parturition prediction within 9 h is 96.9% for the SHM and 84.4% for the BPTVM. Moreover, the SHM can even reach a 75% probability of prediction within three hours of parturition. We conclude that the SHM is more accurate and is more useful for parturition time prediction. When parturition is detected, the proposed algorithm generates a warning signal which can inform human personnel to protect the mother and newborn piglets.

The Limiting Sequence and Proper Ratio of Lysine, Methionine and Threonine for Calves Fed Milk Replacers Containing Soy Protein

  • Wang, Jianhong;Diao, Qiyu;Tu, Yan;Zhang, Naifeng;Xu, Xiancha
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권2호
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    • pp.224-233
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    • 2012
  • The limiting sequence and relative ratio of lysine (Lys), methionine (Met), and threonine (Thr) for calves about 2 mo of age fed milk replacers (MR) containing soy protein are not clearly defined. The objective of the study was to investigate the effect of supplementing MR containing 22% CP, half from soy protein concentrate (SPC, 40.56% CP, flour) and half from whey proteins, with Lys, Met, and Thr to estimate amino acid (AA) sequence and their relative ratio for calves about 2 mo of age. A method of partial deduction of AA was adopted. Twenty-four newborn calves (half males and half females, $40.7{\pm}0.9$ kg of BW) were fed 1 of 4 MR diets for 56 d (n = 6/diet). The diets were supplemented with all (positive control) or with 2 of the 3 AAs: Lys, Met and Thr, (i.e., PC (22% CP, 2.34% Lys, 0.72% Met and 1.80% Thr), PC-Lys (22% CP, 1.64% Lys, 0.72% Met and 1.80% Thr), PC-Met (22% CP, 2.34% Lys, 0.50% Met and 1.80% Thr), and PC-Thr (22% CP, 2.34% Lys, 0.72% Met and 1.26% Thr)). Calves were fed thrice daily; starter (20% CP, 1.03% Lys, 0.30% Met and 0.69% Thr), hay (3.23% CP, 0.29% Lys, 0.12% Met and 0.23% Thr) and water were offered free choice. Starter and hay were only offered beginning on d 36 (after 5 wk) and d 43 (after 6 wk), respectively. BW, body size and blood samples measures were taken every two weeks. Three-day total collection of feed refusals, feces, and urine were recorded starting at d 33 and d 54 of age, respectively. From the results, the limiting sequence and relative ratio between the 3 AAs in calves with different diet structures were calculated. The limiting sequence of the 3 AAs were ranked as Lys, Met and Thr; the proper ratio was 100:29:70 for MR-only diet and 100:30:60 for diets consisted of MR, starter and hay. Nitrogen digestion and utilization and nutrient digestibility were negatively affected by AA deletion treatments. From the evidence of this experiment, it did not appear that the AA limiting sequence was selectively altered by differences in diet structures such as would be encountered in practice. The relative ratio between the 3 AAs varied with the offer of starter and hay to calves, and the average ratio was 100:29.5:65 for calves during 2 to 10 wk of age.

Plasma Protein Profile of Neonatal Buffalo Calves in Relation to the Protein Profile of Colostrum/Milk during First Week Following Parturition

  • Lone, Abdul Gani;Singh, Charanbir;Singha, S.P.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권3호
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    • pp.348-352
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    • 2003
  • An investigation was made into the protein profile of colostrum/milk of ten Murrah buffaloes and of their ten buffalo calves during their first week of neonatal life to study the materno-neonatal transfer of immunoglobulins (Ig). Calves were pail fed 3.5 liter of colostrum and/or milk per calf/day exclusively from their dam. First blood sample from newborn calves was collected before colostrum feeding on the day of birth (day zero) and the sampling continued daily for seven days after colostrum/milk feeding. Colostrum/milk Ig and IgG values were $4.82{\pm}2.60$, $2.19{\pm}1.90$, $1.12{\pm}0.82$, $0.69{\pm}0.44$, $0.59{\pm}0.31$, $0.47{\pm}0.20$, $0.40{\pm}0.22$, $0.40{\pm}0.25$ and $3.58{\pm}1.90$, $1.08{\pm}0.92$, $0.52{\pm}0.40$, $0.31{\pm}0.20$, $0.27{\pm}0.14$, $0.22{\pm}0.08$, $0.18{\pm}0.09$, $0.14{\pm}0.08$ respectively during 0-7 days post partum. The concentration of total colostrum/milk proteins, Ig, IgG and albumin were highest within 12 h post-partum. Thereafter, the concentrations followed a declining trend which may be attributed to the reduced transfer of proteins from the maternal blood, declining synthesis by the mammary glands and/or depletion of stored proteins. The concentrations of plasma Ig and IgG before colostrum feeding on day zero were $0.42{\pm}0.09$ and $0.08{\pm}0.03$ respectively. The levels of plasma Ig were $1.90{\pm}0.37$, $1.80{\pm}0.31$, $1.80{\pm}0.26$, $1.81{\pm}0.28$, $1.78{\pm}0.31$, $1.79{\pm}0.21$, $1.80{\pm}0.32$ and of IgG were $1.57{\pm}0.41$, $1.30{\pm}0.29$, $1.31{\pm}0.21$, $1.27{\pm}0.18$, $1.23{\pm}0.21$, $1.23{\pm}0.16$, $1.26{\pm}0.21$ on days 1-7 after birth after colostrum/milk feeding. The concentrations of total plasma proteins, Ig, IgG were lowest before colostrum feeding and increased significantly (p<0.05) after colostrum feeding in buffalo neonates. The results suggest that the highest amounts of colostral Ig and IgG were available on the day of parturition and thus the calves should receive colostrum as early after birth as possible. Colostrum Ig and IgG concentrations were not correlated to plasma Ig and IgG concentrations in the post-suckle buffalo calves and therefore, colostrum Ig and IgG concentrations were probably not the principle determinants of calf post-suckle plasma Ig and IgG concentrations.

H-Y 항원의 Boosting 방법이 H-Y 항혈청 생산율과 역가에 미치는 효과와 H-Y 항혈청에 의한 토끼 수정란의 성판별에 관한 연구 (Effects of Boosting Methods of H-Y Antigen on Production Rate and Titer of H-Y Antiserum and Studies on Sexing of Rabbit Embryos by H-Y Antiserum)

  • 이명섭
    • 한국가축번식학회지
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    • 제20권3호
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    • pp.271-278
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    • 1996
  • The present study was carried out to sex effectively mouse and rabbit embryos using rat H-Y antiserum and to improve the rate of rat producing H-Y antiserum with H-Y antibody. The H-Y antiserum was prepared from inbred SD strain female rat immunized by intrasplenic injection and subsequent intraperitioneal booster of testis cell of syngenic male newborn rat. the titer of antiserum was identified by in vitro cytotoxicity test of mouse embryos. The rabbit embryos exposed to the H-Y antiserum was classified to the developed (H-Y negative) or delayed (H-Y positive) group. The H-Y negative rabbit embryos were transferred to recipients and sex of offspring was examined. 1. When mouse embryos were exposed to the rat H-Y antisera, the ratio of embryos developed vs delayed was various. The H-Y antisera where the ratio of embryos developed vs delayed showed the range of 40~60% were recognized as having titer of H-Y antibody. 2. When the subsequent intraperitioneal boosters were followed after priming of intrasplenic injection of H-Y antigen, the rate of rat producting the H-Y antiserum with H-U antibody was 13, 27, 70 and 73% in control, 1st B, 2nd B and 3rd B, respectively. The rate in 2nd B and 3rd B was significantly(P<0.05) higher than that in control and 1st B. 3. When the rabbit morulae were exposed to the rat H-Y antiserum with H-Y antibody, the ratio of morulae developed versus delayed was 42:58% and it was close to the natural sex ratio 50:50%. It was confirmed that the rat H-Y antiserum was cross reactive to the rabbit morulae. 4. When the H-Y negative rabbit embryos were transferred to the recipients, the pregnancy rate was 50% and 83% of the newborns were females. In conclusion, the rat H-Y antiserum with high titer of H-Y antibody was able to be obtained from the female rat immunized by the intrasplenic injection followed by the second intrapent oneal booster of testis cells at a week interval. When the rabbit embryos negative to the rat H-Y antiserum were transferred, 83% of the newborns were females.

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Stillbirth rates and their association with swine leucocyte antigen class II haplotypes in Microminipigs

  • Imaeda, Noriaki;Ando, Asako;Matsubara, Tatsuya;Takasu, Masaki;Nishii, Naohito;Miyamoto, Asuka;Ohshima, Shino;Kametani, Yoshie;Suzuki, Shingo;Shiina, Takashi;Ono, Tetsushi;Kulski, Jerzy K.;Kitagawa, Hitoshi
    • Animal Bioscience
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    • 제34권11호
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    • pp.1749-1756
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    • 2021
  • Objective: Microminipig (MMP) is a miniature pig with an extra small body size for experimental use. In the present study, the occurrence of stillbirths and their genetic association with swine leukocyte antigen (SLA) class II haplotypes were evaluated in a population of MMPs. Methods: The occurrences of stillbirth and genetic association with SLA class II haplotypes using 483 stillborn and 2,246 live piglets, and their parents were compared among the three groups of newborn piglet litters; an all stillborn (AS) group consisting of only stillborn piglet litters, a partial stillborn (PS) group consisting of stillborn and live piglet litters, and an all alive (AA) group consisting of only live piglet litters. Results: The incidence of stillborn piglets was 483/2,729 (17.7%). Distributions of litter sizes, numbers of stillborn piglets in a litter, parities, and gestation periods were distinct among the three groups. The frequencies of low resolution haplotype (Lr)-0.7 or Lr-0.23 were higher in the AS group than in the PS or AA groups. In sires, the frequency of Lr-0.7 associated with the AS group was significantly higher in the AS group than with the AA group. In dams, the frequency of Lr-0.23 was significantly higher in the AS group than in the PS or AA groups, whereas the frequency of Lr-0.7 was not significantly different. Conclusion: The incidence of stillborn piglets in MMPs appears to be higher than those in other pig breeds. Several traits related with stillbirths such as the number of stillborn piglets and parities of the AS group were different from those of the PS and AA groups. Specific SLA class II haplotypes were associated significantly with a high incidence of stillbirths and could be used as genetic markers to adopt breeding strategies to lower the rate of stillbirth in MMPs.

복합운동훈련이 신생 흰쥐의 알코올성 소뇌손상 후 운동기능 및 신경연접가소성에 미치는 영향 (The Effects of Complex Motor Training on Motor Function and Synaptic Plasticity After Neonatal Binge-like Alcohol Exposure in Rats)

  • 이선민;구현모;권혁철
    • 한국전문물리치료학회지
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    • 제12권3호
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    • pp.56-66
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    • 2005
  • The purposes of this study were to test that complex motor training enhance motor function significantly, to test change in cerebellum, and to test the synaptic plasticity into the immunohistochemistry response of synaptophysin. Using an animal model of fetal alcohol syndrome - which equates peak blood alcohol concentrations across developmental period - the effects of alcohol on body weight during periods were examined. The effect of complex motor training on motor function and synaptic plasticity of rat exposed alcohol on postnatal days 4 through 10 were studied. Newborn rats were assigned to one of two groups: (1) normal group (NG), via artificial rearing to milk formula and (2) alcohol groups (AG), via 4.5 g/kg/day of ethanol in a milk solution. After completion of the treatments, the pups were fostered back to lactating dams, where they were raised in standard cages (two-and three animals per cage) until they were postnatal 48 days. Rats from alcohol group of postnatal treatment then spent 10 days in one of two groups: Alcohol-experimental group was had got complex motor training (learning traverse a set of 6 elevated obstacles) for 4 weeks. The alcohol-control group was not trained. Before consider replacing with "the experiment/study", (avoid using "got" in writing) the rats were examined during four behavioral tests and their body weights were measured, then their coronal sections were processed in rabbit polyclonal antibody synaptophysin. The synaptophysin expression in the cerebellar cortex was investigated using a light microscope. The results of this study were as follows: 1. The alcohol groups contained significantly higher alcohol concentrations than the normal group. 2. The alcohol groups had significantly lower body weights than the normal group. 3. In alcohol groups performed significantly lower than the normal group on the motor behavioral test. 4. In alcohol-control group showed significantly decreased immunohistochemistric response of the synaptophysin in the cerebellar cortex compared to the nomal group. These results suggest that improved motor function induced by complex motor training after postnatal exposure is associated with dynamically altered expression of synaptophysin in cerebellar cortex and that is related with synaptic plasticity. Also, these data can potentially serve as a model for therapeutic intervention.

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국내 미기록 곤충기생성 응애, Pyemotes moseri Yu et Liang (Acarina: Pyemotidae)의 생식 및 기생 능력 (Reproduction and Parasitization Capacity of an Insect Parasitic Mite, Pyemotes moseri Yu et Liang (Acarina: Pyemotidae) New to Korea)

  • 김세진;이종호;양창열;강택준;조명래;홍기정
    • 한국응용곤충학회지
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    • 제54권4호
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    • pp.393-400
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    • 2015
  • 국내 미기록종 Pyemotes moseri Yu et Liang (Acarina: Pyemotidae)는 곤충기생성 응애로 매실 씨앗 속 유충에서 처음 발견되었다. 발견당시 응애가 기생하고 있었던 기주의 미토콘드리아 유전자를 증폭하여 염기서열을 분석한 결과 복숭아씨살이좀벌의 유충으로 밝혀졌다. 본 연구는 실험실 조건하에서 P. moseri의 번식과 기생 능력을 조사하였다. 복숭아씨살이좀벌의 유충을 기주로 이용하여 P. moseri의 교미한 암컷 성충을 사육하면서 주기적으로 관찰하여 새로 태어나는 자손의 수와 성별을 조사한 후 제거하였다. 기생 능력 조사는 원예용 상토가 깔린 스테인레스 바트에 대량 사육한 응애가 들어 있는 튜브와 복숭아씨살이좀벌 유충이 가해한 매실 씨앗을 함께 담은 후 지퍼백에 넣어 인큐베이터에 보관하였다. 복숭아씨살이좀벌 유충 또는 번데기에 응애의 기생 여부를 확인하고자 한달 후 매실 씨앗을 조사하였으며 본 실험은 5반복씩 3회 실시하였다. 교미한 암컷이 기생하기 시작한 이후부터 생식이 끝날 때까지의 기간은 평균 24.4일(n=8)이었으며 교미한 암컷 한 마리당 평균 104.0마리(n=8)의 암컷을 낳았디. 복숭아씨살이좀벌의 유충 또는 번데기가 들어 있는 매실 씨앗은 바트당 평균 7개 이상이었고 이중 단 2개의 씨앗에서만 기생에 성공한 응애를 관찰하였다.

신생 백서의 저 산소 허혈 뇌손상에서 항세포사멸사를 통한 resveratrol의 신경보호 효과 (Neuroprotective effects of resveratrol via anti-apoptosis on hypoxic-ischemic brain injury in neonatal rats)

  • 신진영;서민애;최은진;김진경;서억수;이준화;정혜리;김우택
    • Clinical and Experimental Pediatrics
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    • 제51권10호
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    • pp.1102-1111
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    • 2008
  • 목 적: Resveratrol은 주로 포도나무의 과실이나 잎 부위에서 추출되는 성분으로, 주로 심질환에서 암 예방 효과, 항염증 효과, 항산화 효과의 기능이 밝혀지고 있다. 최근 성인에 대한 신경보호 효과가 있는 것으로 알려졌지만. 신생아에서 연구는 아직까지 없다. 그래서 본 연구에서는 resveratrol이 신생 백서의 저 산소 허혈 뇌손상에서 신경보호 효과가 있는지를 알아보고자 실험하였다. 방 법: 재태기간 18일된 태아 백서의 대뇌피질 세포를 배양하여 1% $O_2$ 배양기에서 저 산소 상태로 뇌세포손상을 유도하여 저 산소군, 저 산소 30분 전 resveratrol 투여군 (1, 10, $30{\mu}g/mL$)으로 나누어 정상 산소군과 비교하였다. 또한, 동물 모델에서는 생후 7일된 백서의 좌측 총 경동맥을 결찰한 후 저 산소 (8% $O_2$) 상태로 2.5시간 노출시켜서 저 산소 허혈 뇌 손상을 유발하였고, 뇌손상 전후 30분에 resveratrol을 체중 kg당 30 mg을 복막내로 투여하였다. 세포사멸사의 관련을 알아보기 위해 Bcl-2, Bax, caspase-3 primer를 이용한 실시간 중합효소연쇄반응과 동일 항체를 이용한 Western blotting을 시행하였다. 결 과: 태아 백서 뇌세포 배양 실험에서 저 산소군의 경우 Bcl-2의 발현이 정상 산소군에 비해 감소하였고, Bax의 발현과 caspase-3의 발현, 그리고 Bax/Bcl-2의 비율은 증가하였다. Reaveratrol을 투여한 실험군의 경우에서는 Bcl-2 발현은 증가하였고, Bax의 발현과 caspase-3의 발현, Bax/Bcl-2의 비율은 저 산소군에 비하여 감소하는 결과를 보였다. 또한 이는 저 산소 허혈 뇌손상 동물 모델에서도 같은 결과를 보였다. 결론: 본 연구에서 resveratrol은 주산기 저 산소 허혈 뇌손상에서 세포사멸사 작용의 억제를 통하여 신경보호 역할을 하는 것을 알 수 있었다.

태아 백서에서 임신 백서의 자궁 내 대동맥 결찰로 유발한 뇌실주위 백질연화증 (Periventricular leukomalacia induced by in utero clamping of pregnant rat aorta in fetal rats)

  • 장윤실;성동경;강샘;박수경;정유진;서현주;최서희;박원순
    • Clinical and Experimental Pediatrics
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    • 제51권8호
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    • pp.874-878
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    • 2008
  • 목 적 : 본연구의 목적은 자궁 내 태아 백서에서 임신 백서의 대동맥 결찰로 허혈증을 유발하여 뇌실주위 PV) 유발 동물실험 모델을 개발하고자 하는 데 있다. 방 법 : 임신일령 21일 분만 직전 상태의 Sprague-Dawley rat를 진정 및 마취시킨 후 소동물용 하바드 인공호흡기를 사용하여 인공호흡을 시행하였고 이후 개복술을 실시하여 수술 겸자로 대동맥을 40분 동안 가역적으로 결찰 하였고, 이후 제왕절개술로 태아백서를 분만하고 인공호흡 등의 심폐소생술을 시행하여 안정화된 후 대리모에서 자라도록 하여 생후 21일에 뇌조직의 검체를 얻었다. 뇌조직의 검체는 관류한 후 고정하여 $10{\mu}m$ 두께의 연속 절편을 만들어서 병리학적 소견과 뇌실확장(ventriculomegaly) 여부를 관찰하였다. 뇌실확장의 정도는 각 연속 절편에서 측정한 전체 뇌 용량에 대한 뇌실용량의 비율로 판단하였다. 결 과 : 임신 백서에서 대동맥 결찰로 자궁 내 허혈증 유발 후 11마리의 태아 백서 중 8마리(73%)의 태아백서가 심폐소생술 시행 후 생존 하였고 정상 대조군은 10마리 모두 생존하였으며 생후 21일에 측정한 체중과 뇌의 중량 모두 허혈군에서 정상 대조군 보다 더 유의하게 감소되었다. 병리학적 소견 상 뇌조직의 연속 절편에서 측정한 뇌실용적의 비율은 허혈군에서 대조군보다 유의하게 증가하여($3.67{\pm}1.21%$ vs. $0.23{\pm}0.06%$) 뇌실 확장이 관찰되었으며 뇌조직의 낭성 병변은 관찰되지 않았으나 뇌조직의 희박화(rarefaction)는 6례에서는 경도로, 2례에서는 중등도로 관찰되었다. 결 론 : 자궁 내 태아백서에서 임신백서의 대동맥 결찰로 허혈증을 유발하여 PVL 유발 동물실험 모델을 개발할 수 있었다.

Catecholamines에 관(關)하여 -제삼편(第三編) 심장(心臟) Catecholamines에 관(關)한 실험적(實驗的) 연구(硏究)- (Experimental Studies on Cardiac Catecholamine Content)

  • 이우주
    • 대한약리학회지
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    • 제9권1호
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    • pp.1-21
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    • 1973
  • During the last decade extensive studios on catecholamines have evolved new knowledge in the physiology and biochemistry of adrenergic mechanism. Cardiac muscle, receiving adrenergic fibres from the stellate, cervical and thoracic ganglia, has been repeatedly shown to have a specific capacity to uptake and to store catecholamines. The catecholamine stores in cardiac muscle have also been shown to be important sites for the action of numerous drugs. Under normal condition, a certain level of catecholamines is maintained in the stores and serves as the basis for studying the changes in the catecholamine content of the heart. Because myocardial catecholamines play such important role in the patho-physiology of the heart, it would be interesting to compare the normal level of myocardial catecholamines among various species of animals. An occasional study has dealt with myocardial catecholamines of several species add ages of animals but these have been insufficiently comprehensive to afford a basis for an understanding of the importance of these amines as related to species and ages. The present investigation was undertaken to determine whether or not there is any significance of myocardial catecholamines in the course of the evolution and development of animals. Seasonal changes, sex difference and regional and subcellular distribution of myocardial catecholamines were also examined. The concentration of cardiac catecholamines was determined by the spectrophotofluorometric procedure described by Shore and Olin. The results obtained were summarized as follows: 1. As animals phylogenetically progressed larger amounts of catecholamines were resent in their hearts. A negligibly small amount of catecholamine was present in the hearts of the clam, a non-vertebrate. Among the vertebrates, cold-blooded animals (snake, turtle, frog, eel and fish) had less myocardial catecholamines than warm-blooded animals, of which aves (fowl and duck) had less than mammalia (cat, dog, rabbit, rat, cow and pig). The ratio of norepinephrine to epinephrine also was greater as the animals progress phylogenetically. 2. Examination of the regional distribution of cardiac catecholamines in warm-blooded animals showed that the content of the auricle was generally higher than that of the septum and considerably than that of the ventricle, but the differences of contents among these regions were not so marked. 3. In the embryonic chick, cardiac catecholamines were firstly detected on the 4th day of incubation, the time before the cardiac innervation of sympathetic nerves. The concentrations of these catecholamines increased but not markedly on the 6th day of incubation, soon after the innervation of sympathetic nerves to the heart. The level of the cardiac catecholamines fluctuated throughout the remainder of embryonic development. 4. In newborn rat hearts, a considerable amount of catecholamines was present. With the development of the rats, the concentrations of myocardial catecholamines increased. The ratio of epinephrine and norepinephrine fluctuated within the range of 40 to 60 pervent. However, as development progressed, the percentage of norepinephrine continued to rise, attaining the adult value of $80{\sim}90%$ after $45{\sim}60$ days. In contrast, the total amount of epinephrine remained fairly constant throughout the animal's development. 5. No significant sexual differences were observed in the concentration of myocardial catecholamines in the developing rat. 6. The catecholamines in the rabbit hearts increased during the summer season (from May to August) and maintained a fairly constant level in the other seasons of the year. 7. The subcellular distribution of cardiac catecholamines was examined by differential centrifugation of homogenates of cardiac muscles in rabbits, cats and rats. The catecholamines were found to be present approximately 20% in particles of mitochondrial fraction, 45% in particles of microsomal fraction and 35% in soluble supernatant fraction. The particle containing catecholamines in cardiac muscle appears to be two different sizes.

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