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  • Pineal gland

    serch.it?q=Pineal-gland

    Pineal gland or epiphysis (in red in back of the brain). Expand the image to an animated version The pineal gland is a small endocrine gland in the brain of animals with backbones. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The shape of the gland resembles a pine cone from which it derived its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join. It is also called the conarium, kônarion or epiphysis cerebri. The pineal gland is included among a group of specialized neuroendocrine brain structures called the circumventricular organs. Nearly all vertebrate species possess a pineal gland. The most important exception is a primitive vertebrate, the hagfish. Even in the hagfish, however, there may be a "pineal equivalent" structure in the dorsal diencephalon. The lancelet Branchiostoma lanceolatum, the nearest existing relative to vertebrates, also lacks a recognizable pineal gland. The lamprey (another primitive vertebrate), however, does possess one. A few more developed vertebrates lost pineal glands over the course of their evolution. The results of various scientific research in evolutionary biology, comparative neuroanatomy and neurophysiology, have explained the phylogeny of the pineal gland in different vertebrate species. From the point of view of biological evolution, the pineal gland represents a kind of atrophied photoreceptor. In the epithalamus of some species of amphibians and reptiles, it is linked to a light-sensing organ, known as the parietal eye, which is also called the pineal eye or third eye. René Descartes believed the human pineal gland to be the "principal seat of the soul". Academic philosophy among his contemporaries considered the pineal gland as a neuroanatomical structure without special metaphysical qualities; science studied it as one endocrine gland among many.

  • Melatonin receptor

    serch.it?q=Melatonin-receptor

    A melatonin receptor is a G protein-coupled receptor (GPCR) which binds melatonin. Three types of melatonin receptors have been cloned. The MT1 (or Mel1A or MTNR1A) and MT2 (or Mel1B or MTNR1B) receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype MT3 (or Mel1C or MTNR1C) has been identified in amphibia and birds.

  • Melatonin

    serch.it?q=Melatonin

    Melatonin is a hormone, produced by the pineal gland among other locations, which regulates wakefulness. As a medicine, it is used to treat insomnia; however, evidence of benefit is unclear. One review found onset of sleep occurred 6 minutes faster with use but found no change in total time asleep. Side effects from supplements are minimal at low doses. In animals, melatonin is involved in the entrainment (synchronization) of the circadian rhythms including sleep-wake timing, blood pressure regulation, seasonal reproduction. Many of its biological effects are produced through activation of melatonin receptors, while others are due to its role as an antioxidant, particularly in the protection of nuclear and mitochondrial DNA. In plants it functions as a first line of defense against oxidative stress. Melatonin was discovered in 1958. Melatonin is sold over the counter in the United States, Canada and some European countries. In other countries, it may require a prescription or be unavailable. A month's supply costs about 1 USD as of 2017.

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