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Pinealocyte
About: Pinealocyte is a research topic. Over the lifetime, 1605 publications have been published within this topic receiving 55609 citations.
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TL;DR: Melatonin rhythmicity in the turkey pineal gland and retina is regulated both by light and the endogenous circadian clock, and the rapid dampening of the rhythms under DD suggests that of these two regulatory factors, environmental light may be the primary stimulus in the maintenance of the high amplitude melatonin rhythms in the Turkey.
37 citations
TL;DR: The similarity in emission spectra obtained from the pineal gland and a 5-hydroxytryptamine (5-HT)-containing protein model and the results of pharmacologic specificity tests indicated that pineal FIF is derived from 5-HT.
Abstract: The formaldehyde-induced fluorescence (FIF) of pineal sections of the rat was measured quantitatively under instrumental conditions causing minimal photodecomposition. Fluorescence measurements on different sections of one pineal gland showed only little variation. Also the difference between animal variation was small, which enabled us to use groups of five to six animals for appropriate determinations. The similarity in emission spectra obtained from the pineal gland and a 5-hydroxytryptamine (5-HT)-containing protein model and the results of pharmacologic specificity tests indicated that pineal FIF is derived from 5-HT. Pineal 5-HT seemed to be stored in two compartments: the pinealocytes and the sympathetic nerve fibers. Reserpine, a drug depleting the neuronal 5-HT pool selectively, induced about 30% decrease in chemically detectable 5-HT content, indicating that 30% of total pineal 5-HT content was stored in the nerve fibers, and 70% was stored in the pinealocytes. FIF was not affected by reserpine,...
37 citations
TL;DR: The results obtained point to the secretion of androgens and the insufficiency of the antiandrogenic function of the pineal gland both in auditory stress and ulcer disease.
Abstract: A short survey of the results of our previous research into the protective role of the pineal gland against stress is given. The neuroendocrine aspect of a chronic auditory stress and the neuroendocrine aspect of ulcer disease in man were studied. Auditory stress: hypertrophy and hyperplasia of pinealocytes, hyperplasia of the STH, FSH, LTH and TSH cells, hypertrophy of the nuclei and nucleoli of the neuroglandular cells of the supraoptic and paraventricular nuclei, pronounced hyperplasia of the cells of the reticular zone of the adrenal gland, involution of the seminal epithelium, hyperplasia of the Leydig cells. Ulcer disease: numerous glial plates, cavities and acervuli in the pineal gland, numerous granules and vacuoles in the FSH cells, large and eccentrical nuclei in the LH cells, hyperplasia of the cells of the reticular zone of the adrenal gland, presence of the seminal tubules marked by signs of involution, hyperplasia of the Leydig cells. The results obtained point to the secretion of androgens and the insufficiency of the antiandrogenic function of the pineal gland both in auditory stress and ulcer disease. The anticancerogenic effect of the pineal gland would be based on its antiandrogenic function.
37 citations
TL;DR: It is proposed that circadian pineal 5-LO expression might play a role in circadian regulation of pineal functioning.
Abstract: In lymphocytes, the pineal hormone, melatonin, suppresses 5-lipoxygenase (5-LO) gene expression. Because circadian fluctuations in melatonin content are prominent in the pineal, we hypothesized that 5-LO mRNA level in this gland is greater when melatonin is low (day) than at night. Using the reverse transcription/polymerase chain reaction we assayed the levels of mRNAs coding for 5-LO, serotonin N-acetyltransferase (NAT), and for a constitutive gene, cyclophilin, in rat pineals obtained at 10:30-11:00 h (day) or 24:30-01:00 (night). Cyclophilin mRNA was not affected by circadian rhythm, whereas 5-LO and NAT were affected in an opposite manner: 5-LO mRNA was high during the day, NAT mRNA at night. We propose that circadian pineal 5-LO expression might play a role in circadian regulation of pineal functioning.
37 citations
TL;DR: It is raised the possibility that suprachiasmatic nucleus vasopressin output mediates some of the effects of melatonin on seasonal or circadian responses, as well as investigating the role of MEL1a receptor mRNA in seasonal responses.
Abstract: Durational melatonin signals, cued by the photoperiod and generated by the pineal gland, are processed in the brain to induce seasonally appropriate physiological and behavioural adaptations. The melatonin receptor subtype MEL1a (also known as mt1) appears to regulate seasonal responses. Single label in situ hybridization for MEL1a receptor mRNA revealed labelled cells in several brain regions of Siberian hamsters, including the suprachiasmatic nucleus, the paraventricular nucleus of the thalamus, and the reuniens nucleus of the thalamus. To characterize suprachiasmatic nucleus cells containing MEL1a receptor mRNA, we used 35S-labelled cRNA probes for MEL1a receptor mRNA in combination with digoxigenin-labelled cRNA probes for vasopressin, somatostatin, or orphan retinoid Z receptor beta (RZRbeta; a putative nuclear melatonin receptor). Cells in the suprachiasmatic nucleus that contained MEL1a receptor mRNA also contained mRNAs for vasopressin and RZRbeta, but not for somatostatin. These data suggest that suprachiasmatic nucleus vasopressin cells may respond to melatonin signals, raising the possibility that suprachiasmatic nucleus vasopressin output mediates some of the effects of melatonin on seasonal or circadian responses.
37 citations