Pineal body

In the adult pineal, besides blood vessels and connective tissue, at least two definitive cell types are recognisable the pinealocytes (parenchymal cells) and the glial cells (interstitial cells or gliocytes). 

The intracellular signal transduction pathway mediating the inhibitory effects of glutamate on melatonin secretion seems to be coimected to metabotropic receptors (Petralia et al. 1996) since in rat pinealocytes activation of the glutamate metabotropic receptor 3 has been reported to inhibit melatonin synthesis by decreasing cyclic AMP levels and arylalkylamine N-acetyltransferase activity (Yamada et al. 1998). 

Pinealocytes can express different subunits of all major classes of glutamate receptors, i.e. the ionotropic receptors for M-methyl-L-aspartate, a-amino-3-hydroxy-5-methyl-4-isoxazole propionate, and kainate type (Wisden and Seeburg 1993, Sato et al. 1993, TOlle et al. 1993, Petralia et al. 1994), as well as the metabotropic receptors (Petralia et al. 1996). 

Pituitary adenylate cyclase-activating polypeptide (PACAP)-immunoreactive nerve fibres were demonstrated in the rat pineal gland (M0ller et al. 1999). In the superficial pineal grand, the concentration of PACAP-27 was only about 3 % of the concentration of PACAP-38. PACAP is able to upregul-ate neuropeptide Y in neurones of the superior cervical ganglia (May and Braas 1995, Braas and May 1996). Because neuropeptide Y stimulated me- 

Lactate dehydrogenase (EC 1.1.1.27) activity did not show any sexual differences in the isoenzyme pattern in CFY strain rats kept under standard laboratory conditions on 14 h light and 10 h dark periods (Anda et al. 1976). 

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Zipfel, m, tip, point, end, summit lobe, ear, Zirbel-. (Anat.) pineal, -drtise, /. pineal gland, pineal body, -ficlite, -kiefer, /, Swiss pine (Pinua cembra). -nuBB, /. cedar nut (from Pinua cembra). zirka, adv. about, approximately. zifkaBBisch, a. Circassian. 

Serotonin is synthesized via tryptophan and 5-hydroxytryptophan with decarboxylation of the latter (Fig. 25-12). Within the pineal body of the brain and in the retina, serotonin is acetylated to N-acetylseroto-nin,782/783 which is then O-methylated to melatonin, the pineal hormone (Fig. 25-12). A specific inhibitor of serotonin synthesis is p-chlorophenylalanine, and studies with this and other inhibitors suggest that serotonin is required for sleep.784... 

There are metaphysical statements about the nature of the psi receptor. In some traditions, psi supposedly works through the third eye (pineal body) in others, through the heart chakra. But these statements are not scientifically useful because they do not provide sufficient detail that can be tested and thus verified or disproved. At present, we have no idea what the organ for psi reception might be, or indeed whether it is one general-purpose receptor or a variety of them. 

The result of this anatomical characteristic of endothelial cells in the CNS is an increased resistance to water-soluble and ionized drugs entering the brain, and cerebrospinal fluid (CSF), from capillary blood. However, in a few areas of the brain the barrier is absent. These areas include the lateral nuclei of the hypothalamus, the area postrema of the fourth ventricle, the pineal body, and the posterior lobe of the hypophysis. Highly lipophilic compounds can cross the barrier. Tranquilizers such as diazepam and its analogs are known to gain access rapidly to the CSF with a half-life (tm) entry time of less than 1 minute. 

Of much interest is the recent discovery of substances closely related to the harmala alkaloids in animals. One of these is adrenoglomerulotropine, a hormone of the pineal body, the chemical identity of which has been indicated as 2,3,4,9-tetrahydro-6-methoxy-i-methyl-iH-pyrido (3,4,6) indole. This substance is identical to 6-methoxyletrahydroharman which has been shown to be formed in vivo from 5-methoxy tryptamine and acetaldehyde. 6-methoxytetrahydroharman is an isomer of tetrahydro-harmine, one of the alkaloids in Banisteriopsis, and in the African Leptactinia densillora. One more substance, 6-methoxyharmalan, has been shown to derive, at least in vitro, from melatonin, which results from the methylation of acetylserotonin. The enzyme which makes this possible, hydroxyindole O-methyl transferase, has only been found in the pineal body. (Naranjo, in Efron et al. 

Pineal body and circadian rhythms - The pineal body is rich in biogenic amines, and the formation and metabolism of HT, melatonin and other indoles was noted above " > 88,41 j g found there in the... 

The pineal bodies of the monkey, kangaroo and pigeon show circadian behavior similar to that of the rat93. a circadian rhythm of pinealocyte mitotic activity has also been found in rat. ... 

The following molecules occur in the pineal body. Their effects are as varied as their structures. Readers should check (Deulofeu 19067) (Naranjo 1967). 

Adrenoglomerulotropin is a hormone of the pineal body. It Is an aldosterone-stimulating hormone. 

Vasotocin (VT), H-Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Arg-Gly-NH2 (disulfide bond Cys -Cys ), the evolutionary precursor of the neurohypophyseal hormones. VT has been found in the pineal body of mammals and in the cerebrospinal fluid of humans. It is responsible for the regulation of water and mineral metabolism of lower vertebrates. During transition from the cyclostomata to fish, a gene duplication occurred which resulted in the formation of oxytocin and vasopressin. Only the replacement of Ile in VT by Phe led to vasopressin as the mammalian hormone. Precursors of VT (- hydrins) have been isolated from the pars intermedia of Rana esculenta [F. L. Moore, C. A. Lowry, Comp. Biochem. Physiol. C Pharmacol. Toxicol. Endocrinol. 1998, 119, 251]. 

Ippen H (1961) The Pineal Body Hormone Melatonin and the Central Pigment Regulation. Deut Med Wochenschr 86 307... 

Pineal gland, pineal body, epiphysis, Corpus pine-ale a small, cone-shaped, unpaired organ situated between the cerebral hemispheres on the roof of the third ventricle of the mammalian brain. Phylogeneti-cally, the P.g. is a vestigial parietal eye, the light sensitive organ of reptiles. It produces the hormone Melatonin (see). 

Fig. 233. Microglial cells, the lower with numerous pseudopodia, from the pineal body (block 1453) of a rat (No. 15) treated for 8 consecutive days with intraperitoneal injection of 15 mg carbocromene per kg body weigntxday. On the last 5 days of experimentation the animal was exposed to an atmosphere containing only 5 % oxygen for 30 min. Half an hour after the last exposure under pentobarbital anaesthesia (30 mg/kg), the animal was perfused from the abdominal aorta with 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.4). Postfixation with 1 % osmium tetroxide in sodium cacodylate buffer. Embedded in Epon 812 and sectioned at 50 nm. Lead citrate and uranyl acetate. Plate 3440...

A hormone derived from the pineal body which lightens the colour of melanocytes in the frog and which blocks the action oi MSH. In humans it acts on the brain and influences processes such as sleep, ovulation and puberty. Melatonin-secreting pinea tumours are associated with reduced gonadal function. Alter natively pineal destruction can cause precocious puberty. 

Melatonin (N-acetyl-S-methoxytryptamine, Fig. 3) has been found and isolated in the epiphysis or pineal body, a small or n located in the upper part of the brain and phylogenetically related to the third or median eye of reptiles. 

Circadian variations (mainly due to changes in environmental light) of great amplitude have been described for 5-HT, 5-HIAA and melatonin levels in the pineal body the maximum of 5-HT in the rat pineal gland is 90 ng/gland at noon, the minimum 10 ng/gland around midnight... 

Borell and Orstrom (24) investigated the uptake of P by different parts of the brain. The phosphorus present in the pineal body, the anterior and posterior lobes of the h5q>ophysis, and the plexus chorioideus was found to interchange with the labeled phosphate administered by intraperitoneal injection at a much more rapid rate than the other parts of the brain (see page 143) the latter exhibit about the same slow phosphorus interchange as the cerebellum, as seen in Table X. 

Of the accumulated in the course of 40 minutes in the pineal body about 65% are present as acid-soluble phosphorus, 25% as inorganic phosphorus, and 10% as non-acid-soluble phosphorus. 

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