Hypothalamic nuclei

Human GAL1 receptor mRNA has been detected in multiple cell and tissue samples including Bowes melanoma cells, brain, gastrointestinal tract (from esophagus to rectum), heart, prostate, and testes. Rat GAL1 mRNA was detected in olfactory regions, many hypothalamic nuclei (including supraoptic nucleus),... 

Many brain areas are innervated by neurons projecting from both the locus coeruleus and the lateral tegmental system but there are exceptions (Fig. 8.3). The frontal cortex, hippocampus and olfactory bulb seem to be innervated entirely by neurons with cell bodies in the locus coeruleus whereas most hypothalamic nuclei are innervated almost exclusively by neurons projecting from the lateral tegmental system. The paraventricular nucleus (and possibly the suprachiasmatic nucleus, also) is an exception and receives an innervation from both systems. 

As its name implies, the neurohypophysis is derived embryonically from nervous tissue. It is essentially an outgrowth of the hypothalamus and is composed of bundles of axons, or neural tracts, of neurosecretory cells originating in two hypothalamic nuclei. These neurons are referred to as neurosecretory cells because they generate action potentials as well as synthesize hormones. The cell bodies of the neurosecretory cells in the supraoptic nuclei produce primarily antidiuretic hormone (ADH) and the cell bodies of the paraventricular nuclei produce primarily oxytocin. These hormones are then transported down the axons to the neurohypophysis and stored in membrane-bound vesicles in the neuron terminals. Much like neurotransmitters, the hormones are released in response to the arrival of action potentials at the neuron terminal. 

As to the primary developmental actions of testosterone, growth and differentiation appear to be involved. Testosterone or estradiol stimulates outgrowth of neurites from developing hypothalamic neurons that contain estrogen receptors [14, 15]. This is believed to be one of the principal aspects of testosterone action that increases the number and the size of neurons within specific hypothalamic nuclei in males, compared to females [1, 14, 15]. 5a-DHT may have a similar effect on androgen-sensitive neurons. Differentiation of target neurons also occurs in adult brain tissue, hormones like estradiol can evoke responses that differ between adult male and female rats [1,14,15],... 

Mice completely lacking BDNF have reduced sensory neuron survival, other neuronal deflcits, and are viable only a few weeks (Ernfors et al. 1995). Heterozygote BDNF mice exhibit gene dose-dependent reductions in BDNF expression in forebrain, hippocampus, and some hypothalamic nuclei (Kernie et al. 2000 MacQueen et al. 2001) as well as decreased striatal dopamine content, decreased potassium-elicited dopamine release (Dluzen et al. 2002), and... 

Whereas several peptides besides AVP are known to act synergistically with CRH, the only peptide candidate in humans that inhibits the HPA system at all regulatory levels of the system seems to be atrial natriuretic peptide (ANP). ANP has been shown to inhibit the stimulated release of CRH and ACTH in vitro and in vivo. This could be observed in humans as well, where ANP inhibits the CRH-induced ACTH (Keller et al. 1992), prolactin (Wiedemann et al. 1995), and cortisol secretion (StrOhle et al. 1998). ANP is not only synthesized by atrial myocytes (deBold et al. 1985) and released into the circulation, but is also found in neurons of different brain regions (Tanala et al. 1984) where specific receptors have been found. ANP receptors and immunoreactivity have been found in periventricular and paraventricular hypothalamic nuclei, the LC, and the central nucleus of the amygdala. 

The opioids have pronounced effects on the release of hormones from both the pituitary and the hypothalamus. Stimulation of some of the opioid receptors in hypothalamic nuclei decrease the release of dopamine, thus increasing release of prolactin. Opioids bind in the supraoptic nuclei of the hypothalamus and increase the release of antidiuretic hormone (vasopressin). 

Gonadotrophin secretion is under the control of hypothalamus and sex hormones. The hypothalamic nuclei secrete a specific releasing factor for the release of both FSH LH. 

The hypothalamic control of the posterior pituitary is quite different than that of the anterior and intermediate lobes. Specific neurons have their cell bodies in certain hypothalamic nuclei. Cell bodies in the paraventricular nuclei manufacture oxytocin, whereas the supraoptic nuclei contain cell bodies that synthesize ADH. The axons from these cells extend downward through the infundibulum to terminate in the posterior pituitary. Hormones synthesized in the hypothalamic cell bodies are transported down the axon to be stored in neurosecretory granules in their respective nerve terminals (located in the posterior pituitary). When an appropriate stimulus is present, these neurons fire an action potential, which causes the hormones to release from their pituitary nerve terminals. The hormones are ultimately picked up by the systemic circulation and transported to their target tissues. 

In addition to being synthesized in the peripheral nervous system, dopamine is synthesized in the corpus striatum and in the mesocortical, mesolimbic, and tuberoinfundibular systems. Norepinephrine is synthesized and stored primarily in sympathetic noradrenergic nerve terminals, as well as in the brain and the adrenal medulla. Epinephrine is synthesized and stored primarily in the adrenal medulla and, to a certain extent, in the hypothalamic nuclei. 

Aspirin does not alter the normal body temperature, which is maintained by a balance between heat production and dissipation. In a fever associated with infection, increased oxidative processes enhance heat production. Aspirin acts by causing cutaneous vasodilation, which prompts perspiration and enhances heat dissipation. This effect is mediated via the hypothalamic nuclei, as proved by the fact that a lesion in the preoptic area suppresses the mechanism through which aspirin exerts its antipyretic effects. The antipyretic effects of aspirin may be due to its inhibition of hypothalamic prostaglandin synthesis. Although aspirin-induced diaphoresis contributes to its antipyretic effects, it is not an absolutely necessary process, because antipyresis takes place in the presence of atropine. 

Morin AJ, Denoroy L, Jouvet M. Daily variations in concentration of vasoactive intestinal peptide immunoreactivity in hypothalamic nuclei of rats rendered diurnal by restricted-schedule feeding. Neurosci Lett 1993 152 121-124. 

The anatomical visualization of 5-ht1E receptor mRNA has been done in monkey and human brain by in situ hybridization histochemistry (75) see also Fig. 4) and in the guinea pig brain (Fig. 4). The strongest signals are seen in the caudate and putamen, islands of Calleja, external and internal cortical layers (layers II and V in the monkey brain), CA fields and dentate gyms of the hippocampal formation, dorsal and ventral parts of the lateral septal nuclei, and some hypothalamic nuclei. 

M., and Voigt, K. Temperature dependent burst discharges in magnocellu-lar neurons of the paraventricular and supraoptic hypothalamic nuclei recorded in brain slice preparations of the rat. In ... 

Medium-low density of D3 mRNA was found in the agranular insular, fronto-parietal, temporal and occipital cortices, in the hippocampal formation, amygdaloid complex, in thalamic nuclei (anteroventral, anterodorsal, laterodorsal, ventroposterolateral and centromedial nuclei), in the lateral habenula, CPu, STh, VTA, paraventricular and ventromedial hypothalamic nuclei, and superior colliculus (Bouthenet et al., 1991 Landwehrmeyer et al., 1993b Diaz et al., 1995, 2000). No receptor signal could be detected in the pituitary gland (Sokoloff et al., 1990). 

The hypothalamus also shows a more preferential expression of the D2 as compared to the Di family of dopamine receptors (Hurd et al., 2001 see Figs. 7-10). D2 mRNA-expressing cells have been found in most of the major hypothalamic nuclei, in particular the lateral and ventromedial nuclei (Gurevich and Joyce, 1999). Strong expression of the D2 mRNA has also been detected in the premammillary nucleus (Hurd et al., 2001). 

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