SEARCH · PubMed Health

Results for “PINEAL GLAND”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources

PubMed1979

[Neurohumoral control of the pineal gland. A model for the study of neuroendocrine integrative processes].

This article discusses the experimental evidence which suggests that the pineal gland and its innervating neurons are useful paradigms for the study of neuroendocrine integrative processes. The obtained results can be summarized as follows: 1) existence of putative receptors for various hormones (estradiol, testosterone, 5 alpha-dihydrotestosterone, progesterone, prolactin) in the mammalian pineal gland; (2) steroid metabolic pattern in the pineal gland resembling other brain areas involved in gonadotrophic regulation; (3) control of pineal estrophilic and androphilic receptors by adrenergic transmitter through beta-adrenergic receptors and at a translational level; (4) denervation supersensitivity of hormone receptors to neurotransmitter; (5) modification of neuronal activity by hormone treatment at ganglionic and preganglionic sites of action; (6) estrophilic binding sites in ganglia; (7) correlation of pineal responsiveness to hormones with activity of sympathetic nerves; (8) modification by hormones of pineal beta-adrenergic mechanisms; (9) dissociation of hormone effects on the pineal gland in those mediated or modulated by changes in afferent neuronal activity and those relatively unaffected by denervation. Collectively these data indicate that neuroendocrine, endocrine-neural and endocrine-endocrine transducing processes occur in the pinealocytes and superior cervical ganglia.

Animals↗

PubMed1996

The presence of histamine and tele-methylhistamine in the pineal gland of chick.

The levels of histamine (HA) and tele-methylhistamine (t-MeHA) in chick pineal gland were measured by RIA at two time points, i.e. at the end of the light (L) phase and in the middle of the dark (D) phase of 12 h: 12 h L:D cycle. The chick pineal gland showed high HA levels (12.19 and 13.09 ng/pineal at L and D, respectively). The t-MeHA content of chick pineal gland was about 20-times lower than HA level (650.2 and 536.4 pg/pineal at L and D, respectively). An aminoacid precursor of HA, L-histidine (1 g/kg, ip), given to chicks during L or D significantly increased both HA and t-MeHA content of the pineal gland. The L-histidine-evoked elevations in HA level were 2-4-times higher than changes in t-MeHA content. Enzymatic study showed the presence in chick pineal of a moderate activity of L-histidine decarboxylase (HDC), and well expressed activity of HA-methyltransferase (HMT), HA synthesizing and inactivating enzyme, respectively, which suggests that both HA and t-MeHA may be produced within the gland. It is suggested that the metabolic dynamics of the pineal HA may be higher during lighthours than darkhours of the daily light:dark illumination cycle.

Animals↗

PubMed1996

Prenatal development of the sheep pineal gland: an ultrastructural study.

The ultrastructure of the pineal gland of 32 sheep embryos was studied from day 54 of development through birth. Embryos were arranged in four age-groups, defined in terms of the most relevant histological features: group 1 (54 to 67 days of prenatal development), group 2 (71 to 92 days), group 3 (98 to 113 days), and group 4 (118 to 150 days). A primary cell type, designated the pinealoblast, was observed from 54 days until birth; ultrastructurally, this cell was found to contain all the organelles required for hormone synthesis. A second cell population, classified as interstitial cells by virtue of their location among pinealoblasts, appeared at 78 days gestation and persisted until birth. Interstitial cells were scarce and exhibited tropism for the perivascular space. From 118 days gestation until birth, a third cell type, termed the pigmented cell, was visible. Pigmented cells, whose ultrastructural characteristics differed from those of pinealoblasts, contained a large number of pigment granules of varying size and shape. The pineal gland of developing sheep embryos showed considerable innervation and abundant vascularization; this, together with certain ultrastructural characteristics, suggests that the gland has a secretory function in uterine life.

Animals↗

PubMed1992

Histamine-immunoreactive nerve fibers in the rat pineal gland: evidence for a histaminergic central innervation.

An immunohistochemical method that utilizes carbodiimide as a fixative and antisera directed against histamine was applied to investigate the location of histamine in the rat pineal complex. Numerous histamine-immunoreactive cell bodies were observed in different subdivisions of the tuberomammillary nucleus of the posterior hypothalamus, and a few cell bodies were present in the posterior and dorsal part of the periventricular hypothalamic nucleus. Histamine-immunoreactive fibers were observed to leave the posterior hypothalamus in various directions of which one dorsally projecting tract was followed in the periventricular area of the caudal diencephalon to the epithalamus. Several histamine-immunoreactive nerve fibers of this tract continued through the posterior commissure directly into the deep pineal gland. A few immunoreactive fibers were also observed in the habenular commissure. In midsagittal sections, histamine-immunoreactive nerve fibers were observed to enter the pineal stalk from the deep pineal gland. Most of histamine-immunoreactive fibers in the stalk continued towards the superficial pineal gland, but their number decreased in more distal locations of the stalk, indicating that some fibers terminate in the stalk as well. A few fibers were found to terminate in the most rostral part of the superficial pineal gland. The immunoreactive nerve fibers in the epithalamus and pineal complex were endowed with prominent varicosities. Taken together, these results indicate that histaminergic nerve fibers, originating from the posterior hypothalamus, project to the pineal complex of the rat. Histamine must therefore be considered a putative neurotransmitter contained in the central innervation of the pineal gland, but its function in pineal physiology has so far not been elucidated.

Animals↗

PubMedDate not supplied

Fluoride deposition in the aged human pineal gland.

The purpose was to discover whether fluoride (F) accumulates in the aged human pineal gland. The aims were to determine (a) F-concentrations of the pineal gland (wet), corresponding muscle (wet) and bone (ash); (b) calcium-concentration of the pineal. Pineal, muscle and bone were dissected from 11 aged cadavers and assayed for F using the HMDS-facilitated diffusion, F-ion-specific electrode method. Pineal calcium was determined using atomic absorption spectroscopy. Pineal and muscle contained 297+/-257 and 0.5+/-0.4 mg F/kg wet weight, respectively; bone contained 2,037+/-1,095 mg F/kg ash weight. The pineal contained 16,000+/-11,070 mg Ca/kg wet weight. There was a positive correlation between pineal F and pineal Ca (r = 0.73, p<0.02) but no correlation between pineal F and bone F. By old age, the pineal gland has readily accumulated F and its F/Ca ratio is higher than bone.

Aged↗

PubMed2001

SPACRCAN in the developing retina and pineal gland of the rat: spatial and temporal pattern of gene expression and protein synthesis.

SPACRCAN is a hyaluronan-binding proteoglycan that is present in the pineal gland and interphotoreceptor matrix of the retina. Here, we evaluate the pattern of SPACRCAN gene expression and protein appearance during retinal and pineal gland development in the rat. In situ hybridization histochemistry with SPACRCAN riboprobes indicates that hybridization signals are first evident in the retina over developing photoreceptor cells at embryonic day 16 (E16) and in the pineal gland at E21. Immunocytochemistry using a SPACRCAN antibody shows localization of SPACRCAN protein in the developing interphotoreceptor matrix by Postnatal day 5 (P5) and in the pineal gland by P6. These studies suggest that SPACRCAN mRNA expression may occur substantially earlier than the time when SPACRCAN protein is detectable in both the retina and the pineal gland. The period of retinal histogenesis when SPACRCAN is detected first is coincident with the time photoreceptors begin to extend from the outer retinal surface, suggesting that SPACRCAN may participate in the maturation and maintenance of the light-sensitive photoreceptor outer segment.

Age Factors↗

PubMed1996

Orphan nuclear receptor RZRbeta: cyclic AMP regulates expression in the pineal gland.

The nuclear orphan receptor RZRbeta is highly expressed in the rat pineal gland. Recent studies proposed that melatonin, the pineal hormone which regulates a wide variety of circadian-linked phenomena, may be the natural ligand of this receptor. These provocative reports prompted us to learn more about RZRbeta and how it might function in circadian physiology. Here we confirm high expression of this receptor in the pineal gland, and report that pineal RZRbeta expression exhibits a strong daily rhythm. Expression is under photoneural regulation and involves an adrenergic --> cAMP mechanism.

Animals↗

PubMed2005

Embryonic development of the bovine pineal gland (Bos taurus) during prenatal life (30 to 135 days of gestation).

The ontogenesis of the pineal gland of 30 bovine embryos (Bos taurus) has been analysed from 30 until 135 days of gestation by means of optical microscopy and immunohistochemical techniques. For this study, the specimens were grouped into three stages in accordance with the most relevant histological characteristics: Stage 1 (30 to 64 days of prenatal development); Stage 2 (70 to 90 days) and Stage 3 (106 to 135 days). In the cow, it is from 30 days of gestation that the first glandular outline becomes differentiated from the diencephalic ependyma of the third ventricle. This differentiation includes the phenomena of proliferation and multiplication of the ependymal cells that form the epithelium of the pineal outline in development. At 82 days of intrauterine life, in the interior of the pineal parenchyma, we witnessed some incipient pseudoglandular structures that at 135 days were well differentiated. The pineal parenchyma displays a cytology made up of two cellular types of structurally distinct characteristics: pinealoblasts and interstitial cells. Both cellular types begin differentiation at 70 days of embryonic development, the pinealoblasts being greater in number than the interstitial cells. The glandular stroma is formed from the capsular, trabecular and the perivascular connective tissue, filling the interparenchymal space. A dense network of capillaries, which drive across the trabecular connective tissue towards the central glandular zone where their density increases and their calibre is reduced, complete the glandular structure. GFAP positive cells were observed in the embryonic pineal parenchyma in stage 3. At 135 days of gestation, NPY positive fibers entered the pineal gland through the pineal capsule occupying a perivascular localization. Morphological studies of this nature are vital for future use as parameters, indicative of the functional activity of the bovine pineal gland during embryonic development.

Animals↗

PubMed1999

Exo-rhodopsin: a novel rhodopsin expressed in the zebrafish pineal gland.

The zebrafish, a useful animal model for genetic studies, has a photosensitive pineal gland, which has an endogenous circadian pacemaker entrained to environmental light-dark cycles [G.M. Cahill, Brain Res. 708 (1996) 177-181]. Although pinopsin has been found in the pineal glands of birds and reptiles, the molecular identity responsible for fish pineal photosensitivity remains unclear. This study reports identification of a novel opsin gene expressed in the zebrafish pineal gland. The deduced amino acid sequence is similar to, but not identical (74% identity) with that of canonical rhodopsin in the zebrafish retina. This novel rhodopsin is expressed in the majority of pineal cells but not in retinal cells, and hence named exo-rhodopsin after extra-ocular rhodopsin. This study first shows that two different rhodopsin genes are expressed in an individual animal each within a unique location. A phylogenetic analysis indicated that the exo-rhodopsin gene was produced by a duplication of the rhodopsin gene at an early stage in the ray-finned fish lineage. As expected, the exo-rhodopsin gene was found in the medakafish and European eel genomes, suggesting strongly that exo-rhodopsin is a pineal opsin common to teleosts. Identification of exo-rhodopsin in the zebrafish provides an opportunity for studying the role of pineal photoreceptive molecules by using genetic approaches.

Amino Acid Sequence↗

PubMed1995

Complementary DNAs for two arylamine N-acetyltransferases with identical 5' non-coding regions from rat pineal gland.

A cDNA library was constructed from the pineal gland of rats injected with isoproterenol and screened with 32P-labeled cDNAs encoding arylamine N-acetyltransferases from rabbit and human liver. Two types of cDNAs for arylamine N-acetyltransferases (A-type and B-type) were isolated. Expression of the cDNAs in Chinese hamster ovary cells indicated that A-type N-acetyltransferase acetylates both arylamines and arylalkylamines, while the B-type enzyme acetylates only arylamines. Therefore, neither the A-type nor the B-type of enzyme seems to be the arylalkylamine N-acetyltransferase involved in melatonin synthesis in the pineal gland. Nucleotide sequence analysis revealed that both A-type and B-type cDNAs code for 290 amino acids, and that they showed 82.8% similarity in the coding region. However, the nucleotide sequence in the 5' non-coding region was identical in the A-type and B-type cDNAs. In addition, the 5' non-coding region contained another possible open reading frame for 79 amino acids. Data base research revealed that the complementary sequence of the 5' non-coding region has high similarity with the coding regions of cDNAs for high-mobility-group proteins (HMG) 1 and 2, which are thought to regulate mRNA transcription.

Amino Acid Sequence↗

PubMed2002

Successful treatment of extracranially metastasized pineal gland germinoma with high-dose methotrexate.

Germinoma of the pineal gland is a rare disease usually confined to the brain which responds well to radiotherapy. Spinal seeding occurs in approximately 4% of cases and distant metastases are extremely rare. We report on a 27-year-old female with an intracranially metastasized pineal gland germinoma, meningeal carcinomatosis and distant bone metastases. Treatment was initiated with intrathecal methotrexate (MTX) and continued with high-dose intravenous MTX. The therapy was very well tolerated apart from reversible hepatic toxicity requiring a dose reduction. The patient was in complete remission after three courses followed by two consolidation cycles; the patient has now been in continuous complete remission for more than 22 months. This is the first report to show that MTX is a potent drug in treating pineal gland germinoma. Long-term side effects of radiotherapy such as reduced mental function or hypopituitarism can probably be avoided. Single-agent high-dose MTX may provide high efficacy with limited adverse effects, especially at a more advanced tumor stage with spinal seeding and extracranial disease.

Adult↗

PubMed1990

Analysis of the human, bovine and rat 33-kDa proteins and cDNA in retina and pineal gland.

A monoclonal antibody (mAb) was produced against a bovine retinal 33-kDa protein. Several clones of 33-kDa protein were isolated from each library of cDNA from human, bovine and rat retinas and rat pineal gland by mAb screening and by hybridization with cDNA probes. Each of the four cDNA sequences was determined and amino acid (aa) sequences were deduced from the nucleotide sequences. The latter were nearly identical in rat retina and rat pineal gland (99.6%) and were similar in human, bovine and rat retina (more than 87%). Each of these cDNAs had one long ORF and encoded 245 or 246 aa. The deduced aa sequences in rat retina and rat pineal gland were virtually identical and the sequences in human, bovine and rat retina were highly homologous (more than 88%). The predicted Mr for each of these proteins was 28,246 in the human, 28,176 in bovine, 28,143 in rat retina, and 28,129 in rat pineal gland. Each of the sequences has a putative site for phosphorylation by A kinase; we have confirmed that the putative site is Ser73. These results show that the 33-kDa proteins in the retina and pineal gland have the same sequences and the same phosphorylation site and suggest that the functional role of this protein is the same in the retina and pineal gland.

Amino Acid Sequence↗

PubMed1980

The role of the pineal gland in stress.

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.

Acoustic Stimulation↗

PubMed1982

Effect of treatment of rats with antidepressants on melatonin concentrations in the pineal gland and serum.

The effect of administration of antidepressant drugs to rats on catecholamine-induced rises in the concentration of melatonin in the pineal gland and serum was studied. Increases in melatonin levels were produced by either the exogenous administration of different doses of L-isoproterenol or by exposure of rats to darkness. Repeated administration of either desmethylimipramine or nialamide reduced significantly the elevation in melatonin concentrations in the pineal gland produced by either L-isoproterenol or darkness. The rise in serum melatonin seen at night was also blunted significantly in rats treated repeatedly with these drugs. By contrast, the concentration of melatonin in either the pineal gland or serum was not reduced in rats given desmethylimipramine or nialamide acutely. In fact, daytime concentrations of melatonin both in the gland and in serum were significantly increased after either acute or repeated treatment with nialamide. The nialamide-induced increase in daytime concentrations of melatonin in the pineal gland was prevented if the rats were treated with propranolol. The diminished hormonal responsiveness produced by the repeated administration of antidepressants occurred at a time when the binding of [3H]dihydroalprenolol to pineal gland homogenates was reduced. Thus, a hormonal response to catecholamines regulated via beta adrenergic receptor activation is reduced by repeated antidepressant treatments in conjunction with the development of beta adrenergic receptor subsensitivity.

Animals↗

PubMed1984

Pineal gland size and serum melatonin levels in male rats are not correlated.

As both the size of the pineal gland and the serum levels of melatonin are known to be variable it was decided to assess whether the two parameters are interrelated. For this purpose male Sprague-Dawley rats were killed at 12.00 and 24.00 h, respectively. Trunk blood was collected for melatonin radioimmunoassay. The pineal glands were prepared for histological examination, serially sectioned, and from planimetric tracings the volume of the gland was computed. Neither at day nor at nighttime was there a correlation between the volume of the pineal gland and the levels of serum melatonin. There was also no correlation between body weight and the volume of the pineal gland or the levels of serum melatonin.

Animals↗

PubMed1998

Tachykinins in the pineal gland: effect of castration and ganglionectomy.

In this investigation, the presence of NKA-immunoreactive substances was determined in pineal glands from intact, castrated and castrated, testosterone-treated male rats. The effect of environmental light, melatonin treatment and superior cervical ganglionectomy on pineal NKA-immunoreactive substances was also investigated. The results obtained show that NKA is present in measurable amounts in the rat pineal, and NPK is probably also present, Orchidectomy was followed by an increase in the content of NKA-immunoreactive substances in the pineal gland. The replacement treatment with testosterone propionate in castrated rats blocked this effect. NKA-immunoreactive substances were not significantly different quantitatively in pineals from rats killed under light or under darkness. The removal of the superior cervical ganglia was followed by a significant increase in the NKA-immunoreactive substance content in the pineal gland of male rats. These results indicate that NKA and other tachykinins are present in the pineal gland of the male rat, and they seem to be regulated by gonadal hormones and the innervation originated from the superior cervical ganglia.

Animals↗

PubMed1984

Morphodynamic response of the pineal gland to initial stress attack.

The influence of an initial stress attack (a subcutaneous saline injection plus rough handling) on the morphofunctional behaviour of the pineal gland was studied. Both light and electron microscopy pointed to an enhanced endocrine activity on the gland parenchyma. The occurrence of the clusters of highly activated light pinealocytes, as well as the appearance of two functionally different types of these cells, revealed that the introduction of the pineal gland to a new stress-induced steady state was based on the gradual promotion of a number of pinealocytes to the level of a high activity. Dark pinealocytes were less numerous and rather engaged in the synthesis than in the secretion. The ultrastructural characteristics of both pinealocyte populations show that the pineal gland meets the secretory demands upon an initial stress attack by a striking discharge of its active compounds and a successive activation of a new elaborative cycle. The morphodynamic conclusion about an enhanced pineal gland secretory activity is fully evaluated in the change of the rate of prolactin surge. A possible impact of the morphodynamic reactivity of the endocrine parenchyma of the pineal gland upon the functional interpretation of the morphological properties of pinealocytes in case of some manipulative procedures with animals was discussed.

Animals↗

PubMed2004

Scanning electron microscopy of the superficial pineal gland of the 15-day-old rat (Rattus norvegicus).

The presence of a cortex and medulla in the superficial pineal gland has been a controversial point in the morphology of this structure in mammals. The published reports indicate contradictory data especially in rodents. In this study the pineal gland of 15-day-old male rats (Rattus norvegicus) were studied, using scanning electron microscopy, in an attempt to determine whether or not a cortex and medulla are apparent in the pineal gland of young rats. The superficial pineal gland of the 15-day-old rat exhibited both a cortex and a medulla; these areas exhibited different structural organizations. The cortex had a thickness of 40-80 microm and the cells did not show a particular arrangement. The center of the gland was composed of a medulla, which had a width of 1000-1200 microm, and consisted of cells arranged in cords; its morphology was distinctly different from that of the cortex.

Animals↗