The role of the pineal gland is to translate the rhythmic cycles of night and day encoded by the retina into hormonal signals that are transmitted to the rest of the neuronal system in the form of serotonin and melatonin synthesis and release. Here we describe that the production of both melatonin and serotonin by the pineal gland is regulated by a circadian-related heteromerization of adrenerg...

Evidence for a role of the pineal gland and its major hormonal product, melatonin, in mammalian reproduction has accumulated for over three decades. In sorting through the masses of data pertaining to this issue, certain facts are becoming established. For example, the pineal gland is clearly involved in seasonal reproductive cycles via transduction of daylength (more properly nightlength) info...

Serotonin (5-hydroxytryptamine, 5-HT), a precursor for melatonin production, is produced abundantly in the pineal gland of all vertebrate animals. The synthesis of 5-HT in the pineal gland is rate limited by tryptophan hydroxylase 1 (TPH1) whose activity displays a twofold increase at night. Earlier studies from our laboratory demonstrate that pineal 5-HT secretion exhibits dynamic circadian rh...

The ultrastructure of the dog pineal gland from the first postnatal day to the seventh month is described. In the first postnatal stages, pineal parenchyma only shows immature proliferative cells with abundant cytoplasmic glycogen. Nerve fibers are seen in the pineal connective tissue spaces. The differentiation of the dog pineal cell types begins in the first postnatal week. Both pinealocytes ...

There is evidence that the trigeminal (Gasserian) ganglia innervate the mammalian pineal gland and serve in its regulation in addition to the sympathetic and cholinergic as well as further influences. By means of immunohistochemical methods, previous studies demonstrated fibers containing calcitonin gene-related peptide (CGRP-LI) or substance P (SP) in the superficial pineal of various mammalia...

The indolic hormone melatonin is produced by the pineal gland according to a daily rhythm. The terminal step of melatonin synthesis is catalysed by hydroxyindole O-methyltransferase (HIOMT, EC 2.1.1.4). Adaptation to constant light or darkness modifies HIOMT activity and concentration. Using a cDNA probe encoding HIOMT, we investigated the effect of environmental lighting on HIOMT gene expressi...

1. The action of N-2'-chloroethyl-N-ethyl-2-methyl benzylamine (xylamine) on rat pineal gland sympathetic innervation was examined. 2. This alkylating agent caused a concentration-dependent increase in pineal gland N-acetyltransferase (NAT) activity in neurologically intact pineal glands that was suppressed in glands previously subjected to bilateral superior cervical ganglionectomy. 3. Xylamin...

Pituitary growth hormone (GH) release in the rat is stimulated via serotoninergic pathways and can be inhibited by treatment with compounds that act as serotonin antagonists, such as cyproheptadine or the pineal gland hormone, melatonin. To investigate a possible role for serotonin in the control of human GH release, the effects of cyproheptadine and melatonin administration on the GH responses...

There is no direct verification of pineal gland involvement in human uveitis. Specimens of pineal tissue are not available during active uveitis in human patients. Naturally occurring uveitis in horses gives us an opportunity to examine tissues during active ocular inflammation. We examined the pineal gland of a horse that was killed because it had become blind during an episode of uveitis. The...

multiple sclerosis is an autoimmune disease of the central nervous system which is accompanied by demyelinating the neurons. the imbalance between the t cell effectors and t cell regulators is thought to have a role in the pathogenesis of the disease. melatonin is a hormone that is secreted by pineal gland which has an important role in circadian rhythm and immune-modulatory effects. melatonin ...