page_title: Median preoptic nucleus
hierarchical_section_title: Median preoptic nucleus
context_page_description: The median preoptic nucleus is located dorsal to the other three nuclei of the preoptic area of the anterior hypothalamus. The hypothalamus is located just beneath the thalamus, the main sensory relay station of the nervous system, and is considered part of the limbic system, which also includes structures such as the hippocampus and the amygdala. The hypothalamus is highly involved in maintaining homeostasis of the body, and the median preoptic nucleus is no exception, contributing to regulation of blood composition, body temperature, and non-REM sleep.
  The median preoptic nucleus is highly involved in three main areas. These include osmoregulation, thermoregulation, and sleep homeostasis. Within each area are many functions. The role that the median preoptic nucleus plays in osmoregulation is in blood composition and volume, including fluid and salt balance, and produces responses ranging from behavioral to endocrine. Thermoregulation includes both responses to infection and to decreased core temperature upon cutaneous exposure to cold, both of which involve the median preoptic nucleus as an important mediator of sensory input and regulatory output.
context_section_description: The median preoptic nucleus is located dorsal to the other three nuclei of the preoptic area of the anterior hypothalamus. The hypothalamus is located just beneath the thalamus, the main sensory relay station of the nervous system, and is considered part of the limbic system, which also includes structures such as the hippocampus and the amygdala. The hypothalamus is highly involved in maintaining homeostasis of the body, and the median preoptic nucleus is no exception, contributing to regulation of blood composition, body temperature, and non-REM sleep.
  The median preoptic nucleus is highly involved in three main areas. These include osmoregulation, thermoregulation, and sleep homeostasis. Within each area are many functions. The role that the median preoptic nucleus plays in osmoregulation is in blood composition and volume, including fluid and salt balance, and produces responses ranging from behavioral to endocrine. Thermoregulation includes both responses to infection and to decreased core temperature upon cutaneous exposure to cold, both of which involve the median preoptic nucleus as an important mediator of sensory input and regulatory output. Sleep homeostasis is involved in both the onset and maintenance of sleep.
  The median preoptic nucleus has excitatory and inhibitory projections to many areas of the brain. It has inhibitory influences through GABAergic projections to the areas of the brain involved in the stimulation of thermogenesis, as well as on wake-active areas of the brain to induce sleep. Microinjection of ethanol, triazolam, and propofol into this area induces sleep in rodents, suggesting that it is involved in their pharmacologic effects on sleep.  Glutamatergic and noradrenergic, as well as other neurotransmitters, have excitatory influences on other areas of the brain. The median preoptic nucleus is highly involved in cardiovascular regulation, including the release of atrial natriuretic peptide by the heart in response to high blood volume. It also is involved in controlling febrile response to infection and stimulation of thirst, among other functions. Both the connectivity and anatomical position of the median preoptic nucleus allow it to be both a relay station and mediator for sensory and regulatory information, and produce neural, endocrine and behavioral responses to maintain homeostasis.
caption: Nuclei of the Hypothalamus: The preoptic area is located in the anterior portion of the hypothalamus, superior to the optic chiasm.
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