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 217 records · Page 12Linked to original sources

PubMed2026

Preserving the Pineal Gland in Perinatal Mouse Brain Preparations.

The pineal gland, a neuroendocrine structure that secretes melatonin, forms from an anlage at the dorsal midline in the embryonic forebrain. At embryonic day (E) 14.5 in the mouse, a pineal diverticulum is seen out-pouching from the roof of the diencephalon between the paired telencephalic vesicles. This diverticulum is in close contact with overlying cartilage, meningeal, and vascular tissue. It is easily lost when the cranial vault is opened to extract the brain at late embryonic/ early postnatal stages. Despite its important neuroendocrine role, the early development of the pineal gland and the signaling mechanisms that regulate this process remain poorly understood, partly due to the difficulty of preserving this structure intact during embryonic stages of mouse brain development. This article presents an innovative dissection procedure that preserves the pineal gland while maintaining its structural integrity and its attachment to the roof of the diencephalon during brain isolation from embryonic stages through postnatal day (P) 7. The procedure is demonstrated using an E18.5 mouse brain and is therefore suitable for downstream applications requiring preservation of tissue architecture, including in situ hybridization, immunohistochemistry, and spatial transcriptomics. The protocol may also be used to isolate the developing pineal gland, thereby improving pineal-specific representation in transcriptomic and proteomic analyses, which is otherwise challenging because of its small size.

Animals↗

PubMed1982

Ultrastructure of the pineal gland of the mink (Mustela vison).

The pineal gland of the mink (Mustela vison) was examined, using light and electron microscopy. Its cellular structure was compared with that of the pineal gland in other mammalian species, including that of a close taxonomic relative, the ferret. The pineal gland of the mink was composed to pinealocytes and neuroglial cells, as well as numerous neuron cell processes and nerve endings, which provide extensive neural input to the pineal gland. A high degree of vascularity, extent of neural innervation, pinealocyte organelles, and presence of extensive pinealocyte processes with secretory granules indicate an active secretory function. This secretory function is postulated to be associated with the onset of the yearly reproductive cycle in the mink.

Animals↗

PubMed1994

Growth factors and extracellular signal-regulated kinases (mitogen-activated protein kinase) in the rat pineal gland.

The present study revealed that the pineal gland expressed basic fibroblast growth factor (bFGF) and FGF-receptor 1 (FGFR1/flg), suggesting that bFGF in the pineal gland acts in an autocrine or paracrine manner, which is mediated by FGFR1/flg. The present study also examined gene expression of the extracellular signal-regulated kinase (ERK) family (ERK1-3) which may be intracellular signal mediators of growth factors. ERK1 [mitogen-activated protein kinase (MAP-kinase)] was strongly expressed throughout the pineal gland, while expression of ERK2 and ERK3 was not found. These findings suggest the presence of a signal pathway from bFGF to ERK1 via FGFR1/flg in the pineal gland.

Animals↗

PubMed2003

Morphology of pineal glands in human foetuses and infants with brain lesions.

The pineal gland is an organ involved in regulation of homeostasis and body rhythms. It plays an important role in the growth foetuses and adaptation of newborns to new environmental conditions. The requirements of foetuses and newborns progressively change during development. The purpose of the study was to evaluate morphological changes of pineal glands in foetuses and infants with brain lesions. The results of our study showed that parenchyma of developing pineal glands was susceptible to injury in most autopsied foetal and infantile cases. Morphological changes in pineal glands were found in 90% of autopsied brains but 100% of the cases had infections. The lesions in the pineal included mainly haemorrhagic, necrotic and cystic changes. In our autopsied foetuses and children, morphological changes in pineal glands were concomitant with various lesions of brain parenchyma. All results of our study lead to the conclusion that the pineal gland during its development is very susceptible to injury. The failure of normal pineal gland development and subsequent impaired production of melatonin decrease resistance of newborns and children to various environmental harmful agents.

Brain↗

PubMed1987

Action spectra of the lateral eyes recorded from mammalian pineal glands.

Single neuronal units from the pineal stalk and the pineal body of hamsters, guinea pigs and rats were recorded during photic stimulation of the lateral eyes in order to identify the retinal photoreceptor that mediates the environmental control of the mammalian pineal. Two cell types could be distinguished: one type was characterized by spontaneous spike discharges that were irresponsive to light stimulation of the eyes and the pineal body; the other, also spontaneously active, responded to flash stimulation of the lateral eye with On- and Off-discharges. With increasing light intensity, the spike frequency of the second response type followed a sigmoidal function up to a saturation level. Spectral sensitivity curves of all dark-adapted animals peaked at 500 nm. During light adaptation (18 microW/cm2) action spectra exhibited an additional maximum in the red (560 nm, rats and hamsters) and in the blue (450 nm, guinea pigs) light, respectively. Chromatic adaptation to orange light diminished the sensitivity at longer wavelengths, whereas adaptation to blue-green light enhanced the sensitivities at longer wavelengths. Thus, the spectral sensitivity recorded from pineal units of hamsters, guinea pigs and rats corresponds to those described for retinal ganglion cells, which indicates that both rods and cones contribute to the light-sensitivity of the mammalian pineal gland. Direct illumination of the pineal gland did not influence the activity of pineal units.

Animals↗

PubMed1982

The influence of the frequency and pattern of sympathetic nerve activity on serotonin N-acetyltransferase in the rat pineal gland.

The activity of the pineal enzyme arylamine: N-acetyltransferase (NAT) was determined following direct stimulation of the preganglionic or post-ganglionic nerves of the superior cervical ganglia. 1. Stimulation of the preganglionic trunks at 10 c/sec during the day or night was sufficient to increase NAT activity approximately 50-fold, to levels comparable to those observed at night in the intact animal. The time course of this effect of nerve stimulation differed between day and night. 2. The responses of pineal NAT to certain frequencies of stimulation were similar for preganglionic and post-ganglionic stimulation. In both cases the responses to stimulation at 5 c/sec appeared to be maximal, 10 c/sec causing no further increase. However, at 10 c/sec, stimulation was more effective post-ganglionically than preganglionically. 3. Various patterns of preganglionic stimulation, having the same average frequency, differed in their ability to increase the activity of NAT. Some, though not all, of these differences between patterns were observed during post-ganglionic stimulation. 4. Unilateral stimulation of the preganglionic nerves produced an increase in NAT activity that was less than half the increase produced by bilateral stimulation, suggesting that the innervation from the two ganglia interact within the pineal gland. 5. These data indicate that changes in the firing rates of sympathetic nerves innervating the pineal gland, within the range of frequencies typically observed for sympathetic neurones, would be sufficient to account for the circadian rhythm in NAT activity observed in the intact rat. Changes in the over-all pattern of sympathetic activity, in addition to changes in the total number of stimuli, could play a significant role in the pineal response.

Acetyltransferases↗

PubMed1994

Morphological assessment in pinealectomy and foetal pineal gland transplantation in rats: Part I.

The effects of pineal gland, an endocrine organ known to affect the physiology of various organs and systems including the hypothalamo-hypophyseal axis, on the morphological characteristics of target organs were investigated in rats after pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region. It was demonstrated that weight gain was significantly slower in pinealectomized male rats (p < 0.01); pituitary gland weight was lower in the pinealectomized group (p < 0.01) and transplantation had no effect on the weight of this organ; weight of adrenal gland and testis were lower after pinealectomy (p < 0.01) but restored back to control levels after transplantation; the mitotic activity in seminiferous tubules increased with pinealectomy and returned back to control indexes after transplantation. Research on hypothalamic catecholaminergic content revealed a diminished histofluorescence in pinealectomized rats which showed a potentiated restoration after transplantation. The innervation of the pineal gland was studied by anterograde and retrograde injections of Wheat Germ Agglutinin Horse Radish Peroxidase from superior cervical ganglion and pineal gland, respectively. It was demonstrated that cell bodies were traced both at the transplanted tissue and hypothalamus. In view of these data, the multifunctional and a probable high level homeostatic harmony regulator essence of pineal gland is discussed.

Adrenal Glands↗

PubMedDate not supplied

The pineal gland: its physiological and pharmacological role.

Our perception of pineal gland function has attained new dimensions during the last decade. The gland is active throughout the life of an individual and secretes melatonin, the major pineal hormone, and many indoles and polypeptides. The secretion of pineal gland is regulated not only by sympathetic nerve fibers but by other central pinealopetal projections also. Many neurotransmitter-receptor sites have been identified recently in the pineal gland. The gland plays an established role in controlling reproduction and is involved in the control of sexual maturation. It has a major influence on the circadian organization of vertebrates including human beings. The hormone melatonin has a potential therapeutic valve in treating disorders that are associated with biological rhythm disturbances like sleep disorders, "jet lag" phenomena and affective disorders. The gland is actively involved in the mechanisms controlling sleep-wakefulness cycle and human mood disorders. It actively participates in the neuroendocrine mechanism controlling stress and acts even as an oncostatic gland. The pineal gland may be considered an "equilibrating-tranquilizing gland" contributing to longevity.

Animals↗

PubMed2003

Gonadotropin-releasing hormone increases melatonin release in the pineal gland of the female rat in vitro.

To evaluate the effect of gonadotropin-releasing hormone (GnRH) on melatonin ( N-acetyl-5-methoxytryptamine) release and its synthesizing enzyme activities in pineal glands, pineals from adult female rats during diestrus were organ-cultured in a medium containing 10 -12, 10 -10, or 10 -8 M GnRH for 6 h. Melatonin release increased significantly in pineals cultured with 10 -10 and 10 -8 M GnRH compared to controls. However, in pineal glands that were organ-cultured in a medium containing 10 -12 to 10 -8 M GnRH, the activity of arylalkylamine N-acetyltransferase, which is the key regulatory enzyme in melatonin biosynthesis, showed no significant difference from controls. Likewise, GnRH at these concentrations had no significant effect on the activity of pineal hydroxyindole- O-methyltransferase, which catalyzes the final step of melatonin biosynthesis. These results show that GnRH stimulates pineal melatonin release, but suggest that GnRH does not affect its melatonin synthesis.

Acetylserotonin O-Methyltransferase↗

PubMed1994

Behavioural assessment of pinealectomy and foetal pineal gland transplantation in rats: Part II.

Pineal gland is an endocrine organ which exerts regulatory effects on the activity of various organs and systems. The present study was undertaken to highlight in experimental animals the possible integrative function of this endocrine organ on a behavioural pattern. Pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region was performed. Behaviour was defined through motor activity induced by low (2 mg/kg) and high (10 mg/kg) doses of amphetamine in rats. It was shown that pinealectomy produced significant different patterns of behaviour induced by low and high doses of amphetamine. In sham operated animals low dose amphetamine induced a significant locomotor stimulation but without stereotyped activity. High dose amphetamine induced stereotyped activity. After pinealectomy even low dose amphetamine produced the behavioural pattern of stereotyped activity resembling a high dose amphetamine-induced behaviour. This differential effect of amphetamine, seen in pinealectomized rats, was completely restored after transplantation. On the other hand, melatonin treatment did not generate a significant alteration of behavioural profile either in the control or pinealectomized group of rats. Results are discussed with regard to the general regulatory function of the pineal gland.

Amphetamine↗

PubMed1990

Ontogeny of light-induced decrease of N-acetyltransferase activity in explanted chick pineal glands.

The ontogeny of chick pineal serotonin N-acetyltransferase (NAT) activity was investigated in explanted chick pineal glands at 4, 10 and 21 d of age. Nocturnal levels of the enzyme and the response of the enzyme to light exposure were determined in pineal glands maintained in short-term culture at each age. The results indicate that nocturnal NAT activity was increased in the glands from older birds. Nocturnal levels of NAT activity at the time of the initiation of the experiment were threefold greater in glands from 21-d-old birds as compared to that in glands from 4-day-old chicks. The response to light was similar in all three ages examined; light induced a significant decrease in NAT activity within 60 min in explanted glands from 4-d-old chicks and within 180 min in the glands from the 10- and 21-d-old chicks. A paradoxical transient increase in enzyme activity occurred immediately (within 5 min) following light exposure which was significant in the glands from the youngest chicks, and present, but more variable, in the older chicks. These data indicate that the nocturnal enzyme activity is greater in glands from older birds, but that light exposure of explanted glands initiates a transient rise followed by a decrease in NAT activity at all three ages.

Acetyltransferases↗

PubMed1999

Increased plasma ACTH in rats exposed to the elevated plus-maze is independent of the pineal gland.

The involvement of the pineal gland in activation of the hypothalamic-pituitary-adrenocortical (HPA) axis evoked by a stressful stimulus (exposure to the elevated plus-maze) was investigated. Plasma ACTH levels were measured in pinealectomized and pineal-intact rats (sham-operated and non-operated) immediately after a 5 min placement into a plus-maze. A statistically significant elevation in plasma ACTH was measured within all groups; however, no statistical differences between pinealectomized and pineal-intact rats were observed. Similarly, comparison of the plasma ACTH basal values obtained from animals only kept in their home cages did not reveal any statistical differences between pinealectomized and pineal-intact rats. From these results it can be concluded that the pineal gland is not involved in anxiety-related behavior and ACTH response.

Adrenocorticotropic Hormone↗

PubMed1990

GABA as a presumptive paracrine signal in the pineal gland. Evidence on an intrapineal GABAergic system.

GABA is present in the pineal gland of several mammals, where it is synthesized in situ as well as taken up from the circulation. This article reviews available information suggesting a local, physiological role of pineal GABA. Both the pinealocytes and the glial pineal cells have the capacity to take up GABA from the extracellular space. The GABA synthesizing enzyme glutamic decarboxylase (GAD) is detectable in the pineal gland; in the bovine pineal GAD exhibits "neuronal-like" properties. By employing a specific antibody against GABA, about 15% of pinealocytes gave a positive reaction in bovine pineal glands. After a depolarizing stimulus, GABA was released from bovine and rat pineal glands by both Ca2(+)-dependent and Ca2(+)-independent processes. By employing neuronal and glial GABA uptake inhibitors, most 3H-GABA release in bovine pineal gland could be attributed to a "neuronal" (presumably pinealocyte) compartment. Several components of the GABA type A receptor supramolecular complex (i.e., GABA binding sites, central-type benzodiazepine binding sites, Cl- ionophore), as well as a minor population of GABA type B receptor sites, were detected in bovine and human pineal glands. In the rat pineals, GABA is released by norepinephrine (NE) acting through alpha 1-adrenoceptors. Physiological concentrations of GABA, by its effect on type A receptor sites, impaired NE-induced melatonin release; by acting on GABA type B receptors, it decreased NE release. Another presumable presynaptic effect of GABA (i.e., to augment maximal velocity and to decrease affinity of NE uptake) was mediated by type A receptor sites. It is proposed that pre- and postsynaptic activity of GABA in the pineal does not differ from that found for GABA interneurons in local circuits of the brain.

Animals↗

PubMed1990

The effect of progesterone and progesterone + estradiol on the morphology of the pineal gland in immature female pigs.

Pineal gland of the immature female pigs treated with progesterone and progesterone and estradiol simultaneously were investigated with light and electron microscopy. Both of the applied hormones influenced the structure of the pineal glands. Inhibitory effect of progesterone on the relative volume of mitochondria, granular vesicles and dense bodies of type one was observed. Administration of progesterone and estradiol simultaneously caused more complicated influence statistically significant increase of pinealocyte nuclei volume and at the same time significant decrease of mitochondria and granular vesicles.

Animals↗

PubMed1980

Pineal gland in rats suffering from malignancy.

Studies of the pineal gland in rats suffering from fibrosarcomas induced by 9, 10-dimethyl-1, 2-benzanthracene have been carried out. The weight of the pineal gland in these animals did not differ from that in control animals. However, the cells and their nuclei in the pineal glands of tumour bearing animals were larger and contained more lipid than those in the pineal glands of control animals. The results indicate that there is increased metabolic activity in the pineal glands of tumour bearing animals.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1979

Characterization of a cytosol progesterone receptor in bovine pineal gland.

The possible existence of pineal progesterone (P) receptors was assessed in 105,000 g supernatants of bovine pineal glands incubated with 3H-P in the presence of 10 microM cortisol. By charcoal adsorption analysis specific binding (defined as the difference between 3H-P binding in the absence and presence of 1,000-fold excess of unlabeled P) attained its maximum after 60 min at 37 degrees C. Binding was abolished by heating the cytosol or by preincubating it with trypsin. A single population of binding sites with a Kd = 1.64 nM and binding site concentration = 34 fmol/mg of cytosol protein was detectable by Scatchard analysis. In competition experiments the B50 progesterone values (nM) were: P (2), 20 alpha-dihydroprogesterone (12), 20 beta-dihydroprogesterone (25), estradiol (158), testosterone (675) and corticosterone (greater than 1,000). After sucrose gradient centrifugation of pineal cytosol incubated with 3H-P a discrete peak of radioactivity in the 7-8 S region of the gradient was observed, and disappeared following incubation with excess unlabeled P. These results indicate that P receptors are present in the bovine pineal gland.

Animals↗

PubMed1990

Development of an organ culture technique capable of monitoring most pineal gland indole metabolites.

An intact pineal gland organ culture technique was developed which utilised radiolabelled tryptophan as the indolic precursor and two-dimensional thin-layer chromatography to separate the various indole metabolites produced. The method was capable of reproducibly separating and quantitating all tryptophan metabolites except 5-methoxytryptophan which co-chromatographed with tryptophan in all the solvent systems evaluated. Noradrenergic stimulation of cultured pineals led to a predictable increase in N-acetyl-serotonin and melatonin production, suggesting that the method was useful for biochemical and pharmacological studies on the pineal gland. Similarly evaluation of the results revealed that a strong linearity existed between N-acetylserotonin and melatonin production and between actual and theoretical methylation as previously reported, again verifying the usefulness of the method developed.

Acetylserotonin O-Methyltransferase↗

PubMed1994

Distribution of cholinergic and dopaminergic receptors in rainbow trout pineal gland.

The involvement of multiple receptors in modulating the function of the pineal gland was investigated by searching for dopaminergic and cholinergic receptors in trout pineal gland. Dopamine D1 and D2 receptors were measured using [3H]SCH23390 and [3H]spiperone, respectively. Muscarinic and nicotinic cholinergic receptors were measured using quinuclidinyl benzilate ([3H]QNB) and [3H]methylcarbamyl choline, respectively. High-affinity choline uptake sites were measured using [3H]hemicholinium-3. The distribution of dopaminergic receptors varied throughout the pineal gland in that the density of D2 receptors, which was higher than that of D1 receptors, was most abundant in the distal region, exhibiting a value of 112 +/- 17 fmol/mg tissue. The distribution of both muscarinic and nicotinic receptors was uniform throughout the pineal gland. However, the highest value for the high-affinity choline transporter (106 +/- 17 fmol/mg tissue) occurred in the proximal portion of the trout pineal gland. The results of these studies indicate that the pineal gland should not be viewed as a homogeneous tissue possessing identical density of various receptors. Furthermore, these results, along with previous data, are interpreted to suggest that different regions of pineal gland may indeed possess unique functions.

Animals↗