Histaminergic innervation

Autoradiography and receptor mRNA studies have shown Hi receptors to be located in most of the brain areas innervated by the ascending histaminergic axons, e.g. cerebral cortex, hippocampus, limbic areas and hypothalamus. Their presence in the cerebellum is not accompanied by appropriate histaminergic innervation. Very few are found in the striatum but this region does show a high density of H2 receptors. H2 receptors are also found with Hi in the cortex, hippocampus and limbic areas, but not in the hypothalamus. Although basically presynaptic the H3 receptor is also found postsynaptically in the striatum and cerebral cortex (Pollard et al. 1993). 

Compared densities of histamine H3 receptors and histaminergic innervation in various areas of rat brain... 

Densities of H3 receptors in rat brain were obtained from Pollard and Bouthenet [4], Pollard et al. [62], and histaminergic innervation from Steinbusch and Mulder [64], Inagaki et al. [65] and Panula et al. [66],... 

Anichtchik OV, Rinne JO, Kalimo H, Panula P (2000) An altered histaminergic innervation of the substantia nigra in Parkinson s disease. Exp Neurol 163 20-30 Anichtchik OV, Peitsaro N, Rinne JO, Kalimo H, Panula P (2001) Distribution and modulation of histamine H3 receptors in basal ganglia and frontal cortex of healthy controls and patients with Parkinson s disease. Neurobiol Dis 8 707-16... 

Most hypnotic drugs act on GABA receptors. It is reasonable to hypothesize that hypnotic actions are mediated by the GABA receptors on wake-promoting neurons innervated by POA sleep-active neurons, but there is little study of this problem. However, there is evidence that GABAergic anesthetics induce c-Fos IR in the VLPO and suppress c-Fos IR in histaminergic neurons (Nelson et al, 2002). 

Sherin, J. E., Elmquist, J. K., Torrealba, F., 8r Saper, C. B. (1998). Innervation of histaminergic tuberomammillary neurons by GABAergic and galaninergic neurons in the ventrolateral preoptic nucleus of the rat. J Neurosci. 18,... 

The neurotransmitter histamine (HA) exerts several functions in the hypothalamus [1-2] including an involvement in the neuroendocrine regulation of pituitary hormone secretion [3]. HA has no effect directly at the level of the pituitary gland, but influences the secretion of anterior pituitary hormones either by an exerted e.g. in the paraventricular nucleus (PVN) on other central transmitters or hypothalamic regulating factors, which subsequently regulate the release of anterior pituitary hormones. In addition, HA acts on the supraoptic nucleus (SON) in the hypothalamus where the posterior pituitary hormones are synthesized and thereby exerts a direct effect on the release of the posterior pituitary hormones. Immunohistochemical studies have revealed that the histaminergic neurons, which originate in the tuberomammillary nuclei of the posterior hypothalamus, densely innervate most of the hypothalamic areas involved in the neuroendocrine control of pituitary hormone secretion [4-5]. Within the last two decades the effect of HA on pituitary hormone secretion have been explored in several studies and it has been... 

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