Showing papers on "Pinealectomy published in 2016"

Prospective Study on Salivary Evening Melatonin and Sleep before and after Pinealectomy in Humans

Abstract: Melatonin is secreted systemically from the pineal gland maximally at night but is also produced locally in many tissues. Its chronobiological function is mainly exerted by pineal melatonin. It is a feedback regulator of the main circadian pacemaker in the hypothalamic suprachiasmatic nuclei and of many peripheral oscillators. Although exogenous melatonin is approved for circadian rhythm sleep disorders and old-age insomnia, research on endogenous melatonin in humans is hindered by the great interindividual variability of its amount and circadian rhythm. Single case studies on pinealectomized patients report on disrupted but also hypersomnic sleep. This is the first systematic prospective report on sleep with respect to pinealectomy due to pinealocytoma World Health Organization grade I without chemo- or radiotherapy. Before and after pinealectomy, 8 patients completed questionnaires on sleep quality and circadian rhythm (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Morningness-Eveningness Questionnaire), 2 nights of polysomnography, salivary evening melatonin profiles, and qualitative assessment of 2 weeks of actigraphy and sleep logs. Six patients were assessed retrospectively up to 4 years after pinealectomy. Before pinealectomy, all but 1 patient showed an evening melatonin rise typical for indifferent chronotypes. After pinealectomy, evening saliva melatonin was markedly diminished, mostly below the detection limit of the assay (0.09 pg/mL). No systematic change in subjective sleep quality or standard measures of polysomnography was found. Mean pre- and postoperative sleep efficiency was 94% and 95%, and mean sleep-onset latency was 21 and 17 min, respectively. Sleep-wake rhythm during normal daily life did not change. Retrospective patients had a reduced sleep efficiency (90%) and more stage changes, although this was not significantly different from prospective patients. In conclusion, melatonin does seem to have a modulatory, not a regulatory, effect on standard measures of sleep. Study output is limited by small sample size and because only evening melatonin profiles were assessed.

Effect of melatonin on monochromatic light-induced T-lymphocyte proliferation in the thymus of chickens.

Abstract: A total of 360 post-hatching day 0 (P0) Arbor Acre male broilers, including intact, sham operation and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) from a light-emitting diode (LED) system until for P14. We studied the effects of melatonin and its receptors on monochromatic light-induced T-lymphocyte proliferation in the thymus of broilers. The density of proliferating cell nuclear antigen (PCNA) cells and the proliferation of T-lymphocytes in response to Concanavalin A (ConA) in GL significantly increased both in vivo and in vitro (from 9.57% to 32.03% and from 34.30% to 50.53%, respectively) compared with other lights (p<0.005) and was strongly correlated with melatonin levels in plasma (p<0.005). Pinealectomy reduced the levels of circulatory melatonin and the proliferation of T-lymphocytes and eliminated the differences between GL and other lights (p<0.005). However, exogenous melatonin (10(-9)M) significantly increased the proliferative activity of T-lymphocyte by 9.64% (p=0.002). In addition, GL significantly increased mRNA expression levels of Mel1a, Mel1b and Mel1c receptors from 21.09% to 32.57%, and protein expression levels from 24.43% to 42.92% compared with RL (p<0.05). However, these effects were blocked after pinealectomy. Furthermore, 4P-PDOT (a selective Mel1b antagonist) and prazosin (a selective Mel1c antagonist) attenuated GL-induced T-lymphocyte proliferation in response to ConA (p=0.000). Luzindole (a nonselective Mel1a/Mel1b antagonist), however, did not induce these effects (p=0.334). These results suggest that melatonin may mediate GL-induced T-lymphocyte proliferation via the Mel1b and Mel1c receptors but not via the Mel1a receptor.

Melatonin Mediates Monochromatic Light-induced Insulin-like Growth Factor 1 Secretion of Chick Liver: Involvement of Membrane Receptors.

Abstract: Monochromatic lights influenced the proliferation and differentiation of skeletal satellite cells in broilers by the enhancement of insulin-like growth factor 1 (IGF-1) secretion. However, whether melatonin (MEL)-mediated monochromatic lights influenced the IGF-1 secretion remains unclear. Newly hatched broilers, including intact, sham operation and pinealectomy groups, were exposed to blue (BL), green (GL), red (RL) and white light (WL) from a light-emitting diode system for 14 days. The results showed that GL effectively promoted the secretion of MEL and IGF-1, the expression of proliferating cell nuclear antigen and MEL receptor subtypes Mel1a, Mel1b and Mel1c in the liver compared to BL and RL in vivo. Moreover, those was a positive correlation between MEL and IGF-1 (r = 0.834). After pinealectomy, however, these parameters declined, and there were no differences between GL and other monochromatic light treatments. In vitro, exogenous MEL increased hepatocyte proliferation and IGF-1 secretion. Meanwhile, the MEL enhancements were suppressed by prazosin (selective Mel1c antagonist), followed by luzindole (nonselective Mel1a/Mel1b antagonist), but not suppressed by 4-phenyl-2-propionamideotetralin (selective Mel1b antagonist). These findings demonstrated that MEL mediated the monochromatic light-induced secretion of IGF-1 in chicks' livers by Mel1c and that Mel1a may be involved in this process.

Specific features of chronorhyth- mologic changes of the ion-regu- lating function of the kidneys un- der the hypofunction of the pineal gland.

Abstract: The paper investigates the specific features of chronorhythmologic changes of the ion-regulating function of the kidneys under the hypofunction of the pineal gland. For the study of hypofunction of the pineal gland, animals were maintained under constant light stimulation during 7 days. It has been established that the hypofunction epiphysis point out disturbances of the phasic structure of the ion-regulating function in relation to chronograms of the intact group of rats. In terms of physiological pinealectomy observed in- crease in the excretion of sodium ions (6,11±0,81 mmol/h) and the concentration of this cation in the blood plasma remained elevated around the clock. The obtained results indicate significant changes of integral characteristics of the rhythms of electrolyte metabolism and the important role of the pineal gland in ensuring physiological homeostasis.

Peripheral Innervation of Neuroendocrine-Immune System: The Challenges to Change a Physiological Paradigm

Abstract: Based on the idea that the only functionally relevant innervation of the pineal came from the superior cervical ganglion (SCG), at one time (and still today) pinealectomy and the removal of the SCG (called a superior cervical ganglionectomy) were considered interchangeably as acting via the suppression of pineal melatonin synthesis. However, the neuroendocrine outcome of these procedures is not identical. The neuroendocrine relevance of the SCG is underlined by the number of endocrine, neuroendocrine, and immune structures found in its territory, including, in addition to the pineal, the thyroid and parathyroid glands, carotid body, the pituitary gland, median eminence, and choroid plexus. Studies supporting the existence of such a peripheral channel of communication in the hypothalamic–pituitary, thyroid, and parathyroid responses to stress are reviewed. The final part of the chapter deals with the submaxillary lymph nodes as an experimental model to assess the participation of the autonomic nervous system and melatonin in circadian modulation of the immune response. The clinical implications of the biphasic immune effect of melatonin, that is, increasing immune responses in basal or immunodepressed conditions and decreasing them in inflammatory disorders, are discussed.

Melatonin and rheumatoid arthritis: the role of exogenous hormone and pinealectomy

Abstract: ревматоидный артрит (рА) является хроническим заболеванием соединительной ткани, основной мишенью которого являются периферические суставы. лечение таких пациентов, как правило, проводится препаратами базисной терапии и средствами «скорой помощи» – метотрексатом, нестероидными противовоспалительными препаратами и глюкокортикоидами. Однако этих средств не всегда бывает достаточно, что диктует необходимость поиска новых подходов к лечению данной патологии. Эпифизарный гормон мелатонин (МТ) уже не одно десятилетие привлекает внимание ученых и успел зарекомендовать себя как универсальное терапевтическое средство при различных заболеваниях. Среди прочих свойств было обнаружено, что препарат обладает иммунотропной и противовоспалительной активностью [1]. В связи с этим представлялось интересным изучить его влияние на развитие и течение экспериментального артрита. Материал и методы. Опыты были выполнены на беспородных белых крысах-самцах массой 150– 230 г, проведены согласно международным принципам Европейской конвенции о защите позвоночных животных, используемых для экспериментальных и других целей (Страсбург, 1986). В первой серии экспериментов на 15 крысах изучалась роль экзогенного мелатонина на модели адъювантного артрита. Вторая серия была посвящена влиянию эпифизарного дефицита на поведенческие и гуморальные проявления артрита. Для создания адъювантного артрита (АА) крысам субплантарно в заднюю лапку вводился 0,1 мл адъюванта Фрейнда (PierceBiotechnology, США). Микобактерии в его составе при попадании в организм вызывали аутоиммунное воспаление суставов. На этом фоне изучалось действие МТ в дозах 1 и 5 мг/кг (мелаксен фирмы «Unipharm», США) на течение ревматоидного артрита и сопутствующие ему расстройства поведения. Для сравнения использовали животных, у которых применялся физиологический раствор в идентичных объемах. Препараты вводили с 15 по 28 сутки после введения адъюванта. Результаты оценивали в вечернее время на следующий день после окончания инъекций. При моделировании эпифизарного дефицита выполнялась хирургическая эпифизэктомия (ЭЭ). Для этого у 11 животных трепанировали череп и через разрез в твердой мозговой оболочке пинцетом извлекали железу, целостность которой подтверждали макроскопически. Далее костный лоскут укладывали на место, рану ушивали. В качестве контроля служило такое же число крыс, у которых была сделана ложная операция в виде трепанации черепа без удаления эпифиза. Через 5 суток моделировался АА, последствия которого оценивались спустя 14 и 28 дней. Для регистрации поведенческих расстройств использовали стандартные поведенческие тесты: «открытое поле» (ОП), приподнятый крестообразный лабиринт (ПКЛ), темно-светлая камера (ТСК). В ОП регистрировали горизонтальную двигательную активность (число пересеченных сегментов арены) и вертикальную двигательную активность (вертикальные стойки и обнюхивания отверстий). Показателем поисково-исследовательского поведения служили число стоек и свешиваний с края платформы ПКЛ, количество переходов между отсеками ТСК. Для изучения уровня тревожности в этих же тестах учитывали время, проведенное в открытом («опасном») рукаве и светлом отсеке. © К. В. Ломоносова, 2016 УДК 599.323.4:616.831.45 DOI – https://doi.org/10.14300/mnnc.2016.11083 ISSN 2073-8137

The Beginnings of the Pineal Scientific Era: From the Late Nineteenth Century to Melatonin’s Discovery

Abstract: In the late nineteenth century, and based on histological studies, the mammalian pineal gland was classified as a rudimentary vestigial organ, a remnant of the third eye of the lacertids or cold-blooded vertebrates. In the early twentieth century, there was speculation that the pineal gland was a predominantly glial organ. In 1930, Pio del Rio-Hortega, one of the most outstanding figures of the Spanish Histological School, employed silver staining to study the human pineal gland. Rio-Hortega identified secretory pineal cells and interstitial cells of a neuroglial origin. In 1954, Aaron B. Lerner began working on the isolation of a pineal skin lightening factor in amphibians, which led 4 years later to the identification of melatonin, a finding that had an explosive impact on pineal research.