• Journal of Life Science
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• v.23 no.8
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• pp.1064-1072
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• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.337-351
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• 1996

Melatonin Is a multifunctional hormone secreted from the pineal gland in the middle of cerebrum and cerebellum. Its synthesis and release reflect photopedod;Photopedod is a yearly predictable ambient factor that most animals utilize as an environmental cue for maximum survival. Hamsters maintaln reproductive activity in summer during which day length exceeds night time. Upon the advent of autumnal equinox they undergo gonadal regression. The photoperiodic effects are prevented by removal of the pineal gland and restored by the timed repiacument of melatonin. The results suggest that melatonin constitutes part of control mechanism whereby environmental information is transduced to neuroendocrine signal responsIble for the functional integrity of the reproductive system. From the studies for the action site of melatonin following the treatment of photopedod or melatonin in the lesion of a spedflc portion of hypothalamus, suprachiasmatic nuclei and pars tuberalis are shown to be a consensus site for melatonIn. The action of melatonin. In the regulation of reproduction is largely unknown. It is mainly due to the lack of acute effect of melatonin on gonadotropin secretion. However, reduction of the gonadotropln release and augmentation of the hypothalamic gonadotropin-releasing hormone (GnRH) content by long-term treatment of melatonln Indicate that constant presence of melatonln may partidpate in the regulation of sexual activity via the GnRH neuronal system. The action mechanism by which melatonin exerts Its effect on GnRH neuron needs to be eluddated. The inability of opiold analogues to affect the reproductive hormones in sexually regressed animals by inhibftory photopedod and melatonin suggests that the opioldergic neuron may be a prime intervening mediator. Recent cloning of melatonin receptor will contribute to investigate its anatomical Identification and the action mechanism of melatonin on target tissues at the molecular level.

• Journal of Korean Neurosurgical Society
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• v.37 no.3
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• pp.235-237
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• 2005

Meningioma without dural attachment usually occurs in the intraventricular region, the pineal region, and the sylvian fissure. However, subcortical meningioma located far from such locations is extremely rare. The authors report a case of subcortical anaplastic meningioma without any dural attachment in a 41-year-old woman.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.279.2-280
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• 2002

Ascorbic acid is very well known as one of various ntioxidants and is used very popular in man. Melatonin. an endogenous compound secreted by the pineal gland in human brain has been reported to act as an antioxidant nowadays. The present study was performed to obtain the differences of the radioprotective function of ascorbic acid and combination with melatonin according to the administration dose a day on radiation induced DNA damage in mouse spleen and blood. (omitted)

• Journal of Acupuncture Research
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• v.18 no.3
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• pp.69-78
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• 2001

목적 : 본 연구는 최근 임상에서 많이 사용하는 자하차(紫河車) 약침액(藥鍼液)이 과산화수소($H_2O_2$)로 야기된 송과선 세포의 apoptosis에 있어서 세포 보호에 미치는 영향과 그 기전을 분석하였다. 방법 및 결과 : MTT assay를 이용하여 분석한 결과 처리 시간 및 농도에 따른 세포 독성의 효과가 $H_2O_2$ 투여로부터 관찰되었다. 또한 자하거 약침액은 세포 증식 효과를 나타내었고 자하거 약침액을 전처치하고 $H_2O_2$를 처치하였을 때 세포 독성이 크게 감소되었다. DAPI staining에서 자하거 약침액 투여군은 $H_2O_2$ 투여군에 비해 fragmentation이 억제되었다. TUNEL assay를 통하여 자하거 약침액 투여군은 $H_2O_2$ 투여군에 비하여 TUNEL 양성세포의 발현이 감소되었다. Flow cytometry를 통하여 자하거 약침액 투여군은 $H_2O_2$ 투여군에 비하여 세포주기 중 sub G1 분획의 증가가 억제되었다. 결론 : 이상의 결과를 통하여 자하거 약침액이 $H_2O_2$로 유발된 apoptosis에서 세포보호 효과가 있음이 확인되었다.

• Applied Microscopy
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• v.22 no.1
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• pp.1-14
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• 1992

Parenchyma of the cat pineal body consisted of pinealocytes and glial cells. The pinealocyte, predominant cell type, was characterized by having large mitochondria with pale matrix, abundant polyribosomes, moderately-developed Golgi apparatus, centrioles and occasional cilia. The pinealocyte had one thick and long cytoplasmic process at the one pole of the cell, and slender and shorter processes at the other pole, and in addition occasional short processes from the cell body. These processes contained longitudinally arranged microtubules, and a few mitochondria. Thick processes teminated as bulgings either in the intercellular process-rich area, or in the perivascular border which was formed by glial cell processes. These endings of pinealocyte processes had many small vesicles, mitochondria, and occasional dense bodies. Glial cells with abundant filaments of intermediate type and clear cytoplasmic matrix were fibrous astrocyte. Perikarya of the astrocytes had small and dense mitochondria, moderately developed Golgi apparatus, dense bodies and variable amount of intermediate filaments. Glial cell processes run through the intercellular spaces among the pinealocyte processes. Glial cell of protoplasmic type had no or a few filaments, but it had well-organized rough endoplasmic reticulum, dense mitochondria, well developed Golgi apparatus and many dense granules. Intercellular canaliculi formed by adjacent pinealocytes and glial cell processes were often noted. Within the parenchyma, sympathetic and parasympathetic axons and their endings were noted. These endings were present mostly in the intercellular spaces without having membrane specialization, however, in rare instances, ending with small clear and dense cored vesicles, and large dense cored vesicles formed specialized synapse with a pinealocyte process. Within the perivascular spaces nerve fibers and endings, Schwann cells and pericyte were noted. In rare case pinealocyte process penetrated into the perivascular space through the interuptions of glial border. These results suggest that pinealocyte of the cat has less significance in secretory function and is rather neural type of cell.

• Development and Reproduction
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• v.17 no.2
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• pp.111-119
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• 2013

Golden hamsters reproduce in a limited time of a year. Their sexual activities are active in summer but inactive in winter during which day length does not exceed night time and environmental conditions are severe to them. The reproductive activities are determined by the length of light in a day (photoperiod). Melatonin is synthesized and secreted only at night time from the pineal gland. Duration of elevated melatonin is longer in winter than summer, resulting in gonadal regression. The present study aimed at the influences of continuous melatonin treatments impinging on the gonadal function in male golden hamsters. Animals received empty or melatonin-filled capsules for 10 weeks. They were divided into long photoperiod (LP) and short photoperiod (SP). All the animals maintained in LP (either empty or melatonin-filled capsules) showed large testes, implying that melatonin had no effects on testicular functions. Animals housed in SP displayed completely regressed testes. But animals kept in SP and implanted with melatonin capsules exhibited blockage of full regression by SP. These results suggest that constant release of melatonin prohibits the regressing influence of SP.

• Development and Reproduction
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• v.17 no.3
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• pp.149-177
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• 2013

Living beings are surrounded by various changes exhibiting periodical rhythms in environment. The environmental changes are imprinted in organisms in various pattern. The phenomena are believed to match the external signal with organisms in order to increase their survival rate. The signals are categorized into circadian, seasonal, and annual cycles. Among the cycles, the circadian rhythm is regarded as the most important factor because its periodicity is in harmony with the levels of melatonin secreted from pineal gland. Melatonin is produced by the absence of light and its presence displays darkness. Melatonin plays various roles in creatures. Therefore, this review is to introduce the diverse potential ability of melatonin in manifold aspects in living organism.

• Proceedings of the KSCN Conference
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• 2004.05a
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• pp.439.2-439
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• 2004

Melatonin in mammals, produced by the pineal gland and elsewhere, has shown antioxidant and neuroprotective properties in neuronal cells. We investigated whether melatonin would increase newly-born cells (cell proliferation) in the dentate gyrus of maternally-separated rats. To examine the effect of melatonin on cell proliferation of the dentate gyrus in maternally-separated rats, 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry was performed.(omitted)

• Journal of Yeungnam Medical Science
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• v.1 no.1
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• pp.153-160
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• 1984

The management of pineal region tumors remains controversial. This paper reports a case of pineocytoma which was attempted to improve treatment planning by the use of clinical features, computerized tomography, and markers for germ-cell tumors. A presumptive diagnosis could be made and this tumor less likely to respond to radiotherapy was subjected to primary surgery.