Topic
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: Results indicate that pinealocytes have a single beta-adrenoceptor, of the beta 1-subtype, which mediates adrenergic stimulation of not only cyclic AMP but also cyclic GMP.
11 citations
17 Jul 2020
TL;DR: The studies on the use of melatonin implants in mares to obtain reproductive activity out of the breeding season are now in progress and have verified certain stages in the process by which equine species perceive light.
Abstract: Mares and stallions have their reproductive period during the season where the days are long. This annual reproductive rhythm is controlled by the length of the daylight. Treatment of mares during winter when their ovaries are normally inactive, with an artificial light during 14.5 h per day, beginning around the winter solstice, causes the first ovulation of the year to occur at an earlier date.
Studies have verified certain stages in the process by which equine species perceive light. The light message is transformed into nerve impulse by specialized retinal cells. These impulses are transmitted through the supra-chiasmatic nucleus and the cervical superior nucleus to the pineal gland. The pinealocytes respond to noradrenergic stimulation by secreting melatonin. The administration of exogenous melatonin by subcutaneous implants or by oral route suppresses the photostimulation effect. The studies on the use of melatonin implants in mares to obtain reproductive activity out of the breeding season are now in progress.
The GnRH secretion is regulated by such neuromediators as dopamine, noradrenalin, serotonin and opioids. Naloxone, an opioid antagonist, induces a GnRH secretion that is followed by LH and FSH release, in mares during the winter period of inactivity. The thyroid hormones also seem to act on the annual rhythm of GnRH secretion.
An alternation of one month of short days and one month of long days which suppresses the seasonal cycle of variation in small ruminant males has not yet been shown to have a similar effect on mares or on stallions.
11 citations
TL;DR: It is suggested that norepinephrine releases PGE2 in rat pineals via alpha-adrenoceptors, acting at a post-synaptic site, and that superior cervical ganglionectomy induces alpha- adrenergic supersensitivity in the pinealocytes.
11 citations
TL;DR: In the animals exposed to the magnetic field, a dual morphodynamic response was observed: the peptidergic activity of light pinealocytes was obviously reduced versus the unimpaired stress-stimulated functional engagement of dark Pinealocytes.
11 citations
Journal Article•
TL;DR: It was found that primary mineralization occurs in an organic matrix formed by pinealocytes and that hydroxyapatite also takes place in mineral deposition.
Abstract: Acervuli and fragments of pineal gland obtained from 33 subjects of both sexes and age ranging from 1 to 87 years, (30 autopsy and 3 biopsy specimens) were analyzed by light microscopy, transmission and scanning electron microscopy, X-ray diffraction and X-ray energy dispersive microanalysis. It was found that primary mineralization occurs in an organic matrix formed by pinealocytes and that hydroxyapatite also takes place in mineral deposition. From our analysis, the formation of acervuli appears to be age and sex independent and can be possibly related to the secretory activity of the gland.
11 citations