• 제목/요약/키워드: Internal membrane

검색결과 547건 처리시간 0.031초

Influence of Fimasartan (a Novel $AT_1$ Receptor Blocker) on Catecholamine Release in the Adrenal Medulla of Spontaneously Hypertensive Rats

  • Lim, Hyo-Jeong;Lee, Seog-Ki;Lim, Dong-Yoon
    • The Korean Journal of Physiology and Pharmacology
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    • 제17권1호
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    • pp.99-109
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    • 2013
  • The aim of this study was to determine whether fimasartan, a newly developed $AT_1$ receptor blocker, can affect the CA release in the isolated perfused model of the adrenal medulla of spontaneously hypertensive rats (SHRs). Fimasartan (5~50 ${\mu}M$) perfused into an adrenal vein for 90 min produced dose- and time-dependently inhibited the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM, a direct membrane depolarizer), DMPP (100 ${\mu}M$) and McN-A-343 (100 ${\mu}M$). Fimasartan failed to affect basal CA output. Furthermore, in adrenal glands loaded with fimasartan (15 ${\mu}M$), the CA secretory responses evoked by Bay-K-8644 (10 ${\mu}M$, an activator of L-type $Ca^{2+}$ channels), cyclopiazonic acid (10 ${\mu}M$, an inhibitor of cytoplasmic $Ca^{2+}$-ATPase), and veratridine (100 ${\mu}M$, an activator of $Na^+$ channels) as well as by angiotensin II (Ang II, 100 nM), were markedly inhibited. In simultaneous presence of fimasartan (15 ${\mu}M$) and L-NAME (30 ${\mu}M$, an inhibitor of NO synthase), the CA secretory responses evoked by ACh, high $K^+$, DMPP, Ang II, Bay-K-8644, and veratridine was not affected in comparison of data obtained from treatment with fimasartan (15 ${\mu}M$) alone. Also there was no difference in NO release between before and after treatment with fimasartan (15 ${\mu}M$). Collectively, these experimental results suggest that fimasartan inhibits the CA secretion evoked by Ang II, and cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization from the rat adrenal medulla. It seems that this inhibitory effect of fimasartan may be mediated by blocking the influx of both $Na^+$ and $Ca^{2+}$ through their ion channels into the rat adrenomedullary chromaffin cells as well as by inhibiting the $Ca^{2+}$ release from the cytoplasmic calcium store, which is relevant to $AT_1$ receptor blockade without NO release.

MCF-7 유방암 세포주에 있어서 spermine에 의해 유도된 세포사멸 기작 (Mechanism of Apoptosis Induced by Spermine in MCF-7 Breast Cancer Cells)

  • 장은성;김병기
    • 생명과학회지
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    • 제18권9호
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    • pp.1177-1185
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    • 2008
  • 폴리아민은 미생물에서부터 동.식물에 이르기 까지 모든 세포들에서 발견되는 극성을 띈 분자이다. 세포의 성장과 분화에 폴리아민이 중요한 역할을 한다는 것은 이미 오래 전부터 알려져 온 사실이나 정확한 작용 기작은 잘 밝혀져 있지 않다. 최근에 와서는 폴리아민이 다양한 방법으로 세포 독성을 유발한다는 결과가 보고되고 있다. 본 연구에서는 spm의 세포독성 효과가 세포 내 칼슘이온 농도 증가에 따른 미토콘드리아-의존 기작에 의하여 일어난다는 것을 보여준다. Spm에 의해 유도된 세포 내 칼슘이온 농도 증가는 주로 외부로부터의 칼슘 유입에 의한 것으로 생각되며, 세포 내 칼슘 증가는 미토콘드리아로부터의 cytochrome c 방출과 미토콘드리아막의 탈분극에 의한 membrane potential 변화를 초래하였다. 세포사멸에 주도적인 역할을 하는 caspase의 확인에 있어서는, MCF-7 세포는 caspase-3이 결핍되어서 caspase-7이 중심적인 역할을 하는 것으로 이미 알려져 있다. 본 연구에서 확인 한 결과 spm 처리 시 caspase-7과 -12가 활성화되었다. 또한 세포사멸 조절 단백질인 Bcl-2 종류 단백질들의 발현을 조사 한 결과 세포사멸 억제 단백질인 Bcl-2의 발현은 크게 억제되었으며, 촉진단백질인 Bax는 spm 처리시 단백질 양이 거의 2배로 증가되었다. 이상의 결과에 의하면, spm에 의해 유도되는 세포사멸과정은 세포질 내 칼슘이온 농도 증가에 의한 미토콘드리아의 변화가 주도적인 역할을 하는 것으로 생각된다.

우백혈병의 임상 및 세포형태학적 연구 (Clinical and Cytomorphological Studios on Bovine Leukosis)

  • 김덕환
    • 한국임상수의학회지
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    • 제2권1호
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    • pp.79-104
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    • 1985
  • Clinical and cytomorphological studies were carried out in 32 leukotic cattle from Tokachi and Kushiro districts in Hokkaido during the 12 year period from 1969 to 1980. The leukotic cattle were examined :and divided into four types(15 cases of the adult, 11 cases of the thymic, 4 casas of the calf and 2 cases of the skin types). The results obtained were as follows : 1. As for the frequency of the main clinical signs in each type, In the adult type, the main clinical signs (of decreasing order) are as follows: swelling of the superficial lymph nodes>depression and loss of weight>tachycardia>anorekia, anemia of the visible mucous membrane and tachypnea. Those of the thymic type were swelling of the thymus>swelling of the medial iliac lymph nodes> swelling of the superficial lymph nodes>tachypnea. Those of the calf type were swelling of the auperficial lymph nodes>depression and emaciation>tachypnea>anorexia, tachycardia, anemia of the visible mucous membrane and recumbency. Those of the skin type were generalized urticaria-like lesions in skin and swelling of superficial lymph nodes>and depression and loss of weight in the decreasing order of frequency. In addition, large tumor mass in the pelvic cavity and swelling of the medial iliac lymph nodes were detected through rectal palpation in 33.3% and 100% in the adult type cases, respectively. 2. As for the hematological findings, The frequency of occurrence of decreased erythrocyte counts in the decreasing order were as follows : adult>calf>thymic>and skin types. The increase in the total leukocyte count in the order of decreasing frequency were as follows: calf>thymic>adult>and skin types. The increase in the absolute lymphocyte counts was found to be at a low rate, 62.5% of all the cases examined. By contrast, the increase of 5% or more of abnormal lymphocyte rates was observed at a high rate, 96.9% of the total cases. 3. Abnormal lymphocytes were found in all cases examined for lymph nodes biopsied. 4. From the cytomorphological point of view, leukotic cells were divided into 3 types: reticulum cell, lymphoid cell and monocytic cell types. The adult type leukotic cattle were divided with reticulum cell type (66.7%), the lymphoid cell type(22.6%) and monocytic cell type(6.7%). The thymic type was lymphoip cell type(72.7%) and reticulum cell type(27.3%). In the calf type, all were lymphoid cell type while all of the skin type were reticulum cell type only. 5. The leukotic cattle had higher NP frequency in the blood and lymphoid tissue than non-1 eukotic cattle. Especially the adult type had the highest NP frequency. However, it was not recognized that NP were characteristic of leukotic cattle alone. 6. The above findings lead to the conclusion that the most effective diagnostic methods for bovine leukosis are the confirmation of swelling of the superficial and internal lymph nodes and thymus in addition to appearance of abnormal neoplastic cell in the peripheral blood and lymph nodes biopsied.

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한국근해 병어류의 자원생물학적 연구 1. 병어류의 형태에 관한 연구 (Studies on the Fishery Biology of Pomfrets, Pampus spp. in the Korean Waters 1. Morphology of the Two Species of the Genus Pampus)

  • 김용억;한경호
    • 한국수산과학회지
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    • 제22권5호
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    • pp.241-265
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    • 1989
  • 본 연구는 1986년 6월부터 1988년 8월에 걸쳐 충남대천, 인천소래, 경남흥도, 부산공동어시장 및 충남보령군 녹도 등에서 낭장망으로 채집한 병어와 덕대의 표본을 대상으로 난, 자어의 성장에 따른 외부형태, 내부형태 및 미성어와 성어에 대한 형태를 조사한 결과를 요약하면 다음과 같다. 병어와 덕대의 미수정난은 난경이 각각 $0.83\~1.27mm,\;1.05\~1.41mm$로 거의 구형이며 분리부성난이다. 병어 체장 185.0 mm 이상 개체와 덕대 체장 95.5 mm 개체에서 난이 최초로 성숙한다. 자어의 근절은 병어 13+22=35개, 덕대 $14\~15+23=37\~38$개로 성어의 척추골수와 일치한다. 자치어 외부형태 중 두드러진 특징은 가슴지느러미가 덕대에 비해 병어가 크고 덕대의 상악은 하악보다 돌출되어 있다. 덕대의 자어는 체장 $5.60\~7.25mm$에서 흑색소포가 몸의 중앙부 측면, 양택 선단 측면 및 두부에 산재되어 있고, 체장 16.50 mm의 전후의 개체에서 모든 지느러미 유조가 정수에 달하여 치어기로 이행한다. 덕대는 일반적으로 체장 $8.55\~10.00mm$의 개체에서 턱을 구성하는 악골이 최초로 골화하며 척추골의 골화는 두개골 및 내철골보다 빠르며 대체로 두부쪽에서 꼬리방향으로 골화가 진행된다. 병어와 덕대의 외부형태 식별은 턱의 생김새, 지느러미, 극조와 연조수, 협부의 형태 및 두부 후방에 보이는 미세한 파상무늬 등으로 할 수 있으며, 내부형질로는 척추골수, 새파수, 유문수, 식도낭의 형태, 장의 길이 및 상조골수등에 의한다. 병어와 덕대의 요대골은 전단부분이 견대골 쇄골하단에 접착되어 있으며, 미부의 상미축골은 2개이다.

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Influence of Ketamine on Catecholamine Secretion in the Perfused Rat Adrenal Medulla

  • Ko, Young-Yeob;Jeong, Yong-Hoon;Lim, Dong-Yoon
    • The Korean Journal of Physiology and Pharmacology
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    • 제12권3호
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    • pp.101-109
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    • 2008
  • The aim of the present study was to examine the effects of ketamine, a dissociative anesthetics, on secretion of catecholamines (CA) secretion evoked by cholinergic stimulation from the perfused model of the isolated rat adrenal gland, and to establish its mechanism of action, and to compare ketamine effect with that of thiopental sodium, which is one of intravenous barbiturate anesthetics. Ketamine ($30{\sim}300{\mu}M$), perfused into an adrenal vein for 60 min, dose- and time-dependently inhibited the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (a direct membrane-depolarizer, 56 mM), DMPP (a selective neuronal nicotinic NN receptor agonist, $100{\mu}M$) and McN-A-343 (a selective muscarinic M1 receptor agonist, $100{\mu}M$). Also, in the presence of ketamine ($100{\mu}M$), the CA secretory responses evoked by veratridine (a voltage-dependent $Na^+$ channel activator, $100{\mu}M$), Bay-K-8644 (an L-type dihydropyridine $Ca^{2+}$ channel activator, $10{\mu}M$), and cyclopiazonic acid (a cytoplasmic $Ca^{2+}$-ATPase inhibitor, $10{\mu}M$) were significantly reduced, respectively. Interestingly, thiopental sodium ($100{\mu}M$) also caused the inhibitory effects on the CA secretory responses evoked by ACh, high $K^+$, DMPP, McN-A-343, veratridine, Bay-K-8644, and cyclopiazonic acid. Collectively, these experimental results demonstrate that ketamine inhibits the CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors and the membrane depolarization from the isolated perfused rat adrenal gland. It seems likely that the inhibitory effect of ketamine is mediated by blocking the influx of both $Ca^{2+}$ and $Na^+$ through voltage-dependent $Ca^{2+}$ and $Na^+$ channels into the rat adrenal medullary chromaffin cells as well as by inhibiting $Ca^{2+}$ release from the cytoplasmic calcium store, which are relevant to the blockade of cholinergic receptors. It is also thought that, on the basis of concentrations, ketamine causes similar inhibitory effect with thiopental in the CA secretion from the perfused rat adrenal medulla.

개의 아토피성 피부염에서 분리한 Staphylococcus intermedius 균의 세균단백질의 면역반응 (Immune Response of Bacterial Proteins of Staphylococcus intermedius from Canine Atopic Dermatitis)

  • Park, Hee-myung
    • 한국임상수의학회지
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    • 제21권1호
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    • pp.20-22
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    • 2004
  • 개의 아토피성 피부염의 주된 세균성 감염은 Staphylococcus intermedius에 의해 발생한다. 본 연구의 목적은 아토피성 피부염을 가지고 있는 환견의 혈청과 정상견의 혈청을 이용하여 체액성 면역반응을 유발하는 주된 세균단백질을 규명하는데 있다. 건국대학교 수의과대학 부속동물병원에 내원한 아토피성 피부염 및 표재성 세균성 농피증을 앓고 있는 환견의 혈청 및 정상견의 혈청을 분리하여 본 실험에 사용하였으며 아토피성 피부염을 가지고 있는 환견에서 S. intermedius 균을 분리하였다. Brain heart infusion 액체배지 조건 및 $37^{\circ}C$ 배양조건에서 호기상태로 증균시켰으며 증균후 포도상구균을 PBS완충액에 부유시킨후 원심분리하고 최종적으로 lysostaphin을 이용하여 세균단백질을 분리하였다. 수거한 세균단백질은 SDS-PAGE을 이용하여 단백질을 전기영동하였으며 영동후 nitrocellulose membrane을 이용하여 단백질을 이동시켰다. Western blot은 anti-dog-IgG, 아토피성 피부염의 혈청 및 정상혈청을 이용하였다. 결론적으로 아토피성 피부염의 혈청을 이용해 확인한 S. intermedius의 주요 세균단백질은 18, 31, 75, 및 110 kDa이였다. 현재의 연구결과로 볼 때 아토피성 피부염에 감염된 대부분의 환견은 S. intermedius의 세균단백질에 대한 체액성 면역반응이 유발된다고 생각된다.

축소된 개구리밥 식물체 내 색소체 특성 (Features of Plastids within Reduced Spirodela polyrhiza)

  • 김인선
    • Applied Microscopy
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    • 제41권1호
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    • pp.55-60
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    • 2011
  • 부엽성 개구리밥은 엽상체, 연결사, 뿌리로 이루어진 축소된 수생식물로 엽상체는 특정한 시기에 물속에 가라앉는 휴면구조인 잠아를 형성한다. 식물세포의 분화발달에서 중요한 기능을 수행하는 색소체는 개구리밥의 거의 모든 기관에 분포하며, 특히 잠아 형성 및 수중 침강에 있어서 이들 색소체와의 연계성이 보고되어 있다. 본 연구에서는 개구리밥 식물체 내 모든 조직을 구성하는 각각의 세포들을 대상으로 색소체 특성에 초점을 두어 전자현미경으로 연구하였다. 생장 중의 엽상체는 활발한 분열로 개체를 계속 증식시키고, 특정 시기에 잠아원기를 형성하여 엽상체-잠아원기-잠아-엽상체원기-엽상체의 분화과정을 반복한다. 개구리밥 조직에 발달하는 색소체는 전색소체, 엽록체, 전분체로 크게 대별되며, 특히 색소체의 크기, 틸라코이드막계, 녹말입자 형성 등은 엽상체와 잠아 조직 간에 뚜렷한 차이를 보인다. 엽상체 및 잠아원기 엽육세포에는 비교적 작은 전색소체가 세포질에 분산되어 다수 분포하고, 기질 내에는 틸라코이드막계 및 녹말입자가 거의 형성되지 않는다. 반면, 생장 중의 엽상체에는 엽록체들이 중앙의 큰 액포를 따라 위치하고, 기질에는 그라나를 형성하는 틸라코이드막계가 발달한다. 유사한 형태의 엽록체가 근관에 발달하나 뿌리의 피층 및 연결사 색소체에는 녹말입자는 거의 나타나지 않는다. 잠아원기와는 대조적으로 잠아조직에는 매우 큰 전분체들이 축적된다. 이들 전분체는 기질에 내부 막의 분화 없이 당 축적에 의한 거대 녹말입자를 형성하여 무거운 구조가 된다. 이와 같이 엽상체, 연결사, 뿌리조직에 형성된 엽록체로 광합성을 수행하여 생장발달에 필요한 에너지를 생성 활용하는 반면, 잠아는 에너지 생성이나 활용이 아닌 휴면상태 유지에 필요한 독특한 구조로 각각 발달한다. 축소된 개구리밥 식물체 내 색소체 및 각각의 세포와 조직들은 최소한의 구조로 분화되나 기능은 고도로 분업화된 독특한 수생식물이라 할 수 있다.

Inhibitory Effects of Total Ginseng Saponin on Catecholamine Secretion from the Perfused Adrenal Medulla of SHRs

  • Jang, Seok-Jeong;Lim, Hyo-Jeong;Lim, Dong-Yoon
    • Journal of Ginseng Research
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    • 제35권2호
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    • pp.176-190
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    • 2011
  • There seems to be some controversy about the effect of total ginseng saponin (TGS) on the secretion of catecholamines (CA) from the adrenal gland. Therefore, the present study aimed to determine whether TGS can affect the CA release in the perfused model of the adrenal medulla isolated from spontaneously hypertensive rats (SHRs). TGS (15-150 ${\mu}g/mL$), perfused into an adrenal vein for 90 min, inhibited the CA secretory responses evoked by acetylcholine (ACh, 5.32 mM) and high $K^+$ (56 mM, a direct membrane depolarizer) in a dose- and time-dependent fashion. TGS (50 ${\mu}g/mL$) also time-dependently inhibited the CA secretion evoked by 1.1-dimethyl-4 -phenyl piperazinium iodide (DMPP; 100 ${\mu}M$, a selective neuronal nicotinic receptor agonist) and McN-A-343 (100 ${\mu}M$, a selective muscarinic M1 receptor agonist). TGS itself did not affect basal CA secretion (data not shown). Also, in the presence of TGS (50 ${\mu}g/mL$), the secretory responses of CA evoked by veratridine (a selective $Na^+$ channel activator (50 ${\mu}M$), Bay-K-8644 (an L-type dihydropyridine $Ca^{2+}$ channel activator, 10 ${\mu}M$), and cyclopiazonic acid (a cytoplasmic $Ca^{2+}$-ATPase inhibitor, 10 ${\mu}M$) were significantly reduced, respectively. Interestingly, in the simultaneous presence of TGS (50 ${\mu}g/mL$) and N${\omega}$-nitro-L-arginine methyl ester hydrochloride [an inhibitor of nitric oxide (NO) synthase, 30 ${\mu}M$], the inhibitory responses of TGS on the CA secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644, cyclopiazonic acid, and veratridine were considerably recovered to the extent of the corresponding control secretion compared with the inhibitory effect of TGS-treatment alone. Practically, the level of NO released from adrenal medulla after the treatment of TGS (150 ${\mu}g/mL$) was greatly elevated compared to the corresponding basal released level. Taken together, these results demonstrate that TGS inhibits the CA secretory responses evoked by stimulation of cholinergic (both muscarinic and nicotinic) receptors as well as by direct membrane-depolarization from the isolated perfused adrenal medulla of the SHRs. It seems that this inhibitory effect of TGS is mediated by inhibiting both the influx of $Ca^{2+}$ and Na+ into the adrenomedullary chromaffin cells and also by suppressing the release of $Ca^{2+}$ from the cytoplasmic calcium store, at least partly through the increased NO production due to the activation of nitric oxide synthase, which is relevant to neuronal nicotinic receptor blockade, without the enhancement effect on the CA release. Based on these effects, it is also thought that there are some species differences in the adrenomedullary CA secretion between the rabbit and SHR.

R-(-)-TNPA, a Dopaminergic $D_2$ Receptor Agonist, Inhibits Catecholamine Release from the Rat Adrenal Medulla

  • Hong, Soon-Pyo;Seo, Hong-Joo;Lim, Dong-Yoon
    • The Korean Journal of Physiology and Pharmacology
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    • 제10권5호
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    • pp.273-282
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    • 2006
  • The aim of the present study was to investigate the effects of R-(-)-2,10,11-trihydroxy-N-propylnoraporphine [R-(-)-TNPA], a selective agonist of dopaminergic $D_2$ receptor and S(-)-raclopride, a selective antagonist of dopaminergic $D_2$ receptor, on the secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane-depolarization in the isolated perfused model of the rat adrenal gland, and also to establish its mechanism of action. R-(-)-TNPA $(10{\sim}100\;{\mu}M)$ perfused into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM), DMPP $(100\;{\mu}M)$ and McN-A-343 $(100\;{\mu}M)$. R-(-)-TNPA itself did also fail to affect basal CA output. Also, in adrenal glands loaded with R-(-)-TNPA $(30\;{\mu}M)$, the CA secretory responses evoked by Bay-K-8644 $(10\;{\mu}M)$, an activator of L-type $Ca^2+$ channels and cyclopiazonic acid $(10\;{\mu}M)$, an inhibitor of cytoplasmic $Ca^{2+}-ATPase$ were also inhibited. However, S(-)-raclopride $(1{\sim}10\;{\mu}M)$, given into an adrenal vein for 60 min, enhanced the CA secretory responses evoked by ACh, high $K^+$, DMPP and McN-A-343 only for the first period (4 min), although it alone has weak effect on CA secretion. Moreover, S(-)-raclopride $(3.0\;{\mu}M)$ in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644 and cyclopiazonic acid only for the first period (4 min). However, after simultaneous perfusion of R-(-)-TNP A $(30\;{\mu}M)$ and S(-)-raclopride $(3.0\;{\mu}M)$, the inhibitory responses of R(-)-TNPA $(30\;{\mu}M)$ on the CA secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644, and cyclopiazonic acid were significantly reduced. Taken together, these experimental results suggest that R-(-)-TNPA greatly inhibits the CA secretion from the perfused rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) and membrane depolarization, but S(-)-raclopride rather enhances the CA release by them. It seems that this inhibitory of R-(-)-TNPA may be mediated by stimulation of inhibitory dopaminergic $D_2$ receptors located on the rat adrenomedullary chromaffin cells, while the facilitatory effect of S(-)-raclopride is due to the blockade of dopaminergic $D_2$ receptors, which are relevant to extra- and intracellular calcium mobilization. Therefore, it is thought that dopaminergic $D_2$ receptors may be involved in regulation of CA release in the rat adrenal medulla.

동결 생쥐 난자에서의 calcium 전류 (Calcium current on cryopreservation in mouse oocytes)

  • 강다원;김은심;최창용;박재용;한재희;홍성근
    • 대한수의학회지
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    • 제42권1호
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    • pp.35-43
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    • 2002
  • Cryopreservation is commonly used for an efficient utilization of semen, oocytes and embryos but has disadvantage in the survival, development of the post-thawed eggs. The high risk in the survival, development of eggs after thawing is thought to be caused by inappropriate internal regulation of $Ca^{2+}$ and/or formation of intracellular ice crystals. In this experiment, we tested whether the $Ca^{2+}$ current (iCa), a decisive factor to $Ca^{2+}$ entry, was altered in post-thawed oocytes by using whole cell voltage clamp technique. The quality and survival rates of the oocytes derived from both fresh and frozen groups were examined by morphology and FDA-test. Vitrified oocytes (VOs) were incubated for 4 hr after thawing and then donated to this experiment. Ethyleneglycol-ficoll-galactose (EFG) was used as a cryoprotectant for vitrification. The membrane potential was held at -80 mV and step depolarizations of 250 ms were applied from -50 mV to 50 mV in 10 mV increments. The survival rates showed a higher in VOs vitrified with EFG containing $Ca^{2+}$ than in VOs vitrified with EFG under the $Ca^{2+}$-free condition (82.0% vs 14%). In group with/without $Ca^{2+}$, the survival rates were significantly (P<0.01) difference. In the fresh metaphase II oocytes (FOs), current-voltage (I-V) relationship showed that iCa began to activate at -40 mV and reached its maximum at -10 mV. With same voltage pulses, inward currents were elicited in VOs. I-V relationships observed in VOs were similar to those in FOs. Time constants of activation and inactivation of the inward current shown in VOs were not different to those in FOs. This accordance in I-V relations and time constants in FOs with those in VOs indicates that the inward currents in FOs are unaltered by vitrification and thawing. Therefore, vitrification with EFG does not play as a factor to deteriorate $Ca^{2+}$ entry across the membrane of the oocytes.