Hypothalamus arcuate nuclei

FIGURE 14-2 The histaminergic system of the rat brain. (A) Frontal sections through the posterior hypothalamus showing the location of histaminergic neurons. Arc, arcuate nucleus DM, dorsomedial nucleus LM, lateral mammillary nucleus MM, medial mammillary nucleus MR, mammillary recess PM, premammillary nucleus 3V, third ventricle VMH, ventromedial hypothalamic nucleus. (Modified with permission from reference [5].)... 

The leptin receptor is expressed primarily in regions of the brain known to regulate feeding behavior— neurons of the arcuate nucleus of the hypothalamus... 

Recent results from our laboratory establish CaMKKp as a physiologically relevant AMPK in mice and suggest that it mediates the ghrelin-induced activation of AMPK and NPY in hypothalamic NPY neurons. In situ hybridization revealed that CaMKKp mRNA is expressed in the arcuate nucleus of the hypothalamus. Mice null for the CaMKKp gene show decreased hypothalamic AMPK phosphorylation and activity as well as NPY/AgRP mRNAs. The CaMKKp null mice fed... 

GnRH is produced in the arcuate nucleus of the hypothalamus. GnRH is secreted into the hypothalamic-pituitary venous plexus and binds to cell surface receptors of the anterior pituitary gonadotroph cells. Pulsatile GnRH secretion is required to stimulate the gonadotroph cell to produce and release luteinizing hormone (LH) and follicle stimulating hormone (FSH). 

The tuberoinfundibular system, which originates in the arcuate nucleus of the hypothalamus and projects to the median eminence. 

The medial accumbens shell, via its reciprocal connections with the lateral hypothalamus (Heimer et al., 1991 Brog et al., 1993), receives information on the internal state from the arcuate nucleus of the hypothalamus and in turn modulates the release of fixed motor patterns of feeding after local infusion of GLU-antagonists and GABA agonists (Maldonado-Irizarry et al., 1995). 

Fig. 1. Location of dopaminergic perikarya (Au-A15) are depicted schematically on frontal sections (B-F) through the diencephalon of the rat. Section A is a sagittal view of the rat brain depicting the rostrocaudal location of frontal sections B-F. Abbreviations AH, anterior hypothalamus ARC, arcuate nucleus BST, bed nucleus of the stria terminalis f, fornix ic, internal capsule inf, infundibulum me, median eminence mt, mamillothalamic tract OC, optic chiasm ot, optic tract PH, posterior hypothalamus PIT, pituitary gland PeV, periventricular nucleus PVN, paraventricular nucleus RCH, retrochiasmatic area SON, supraoptic nucleus VMN, ventromedial nucleus ZI, zona incerta.

Ibata Y, Kawakami F, Okamura H, Obata-Tsuto HL, Morimoto N, Zimmerman EA (1985) Light and electron microscopic immunocytochemistry of P-endorphin/ P-LPH-like immunoreactive neurons in the arcuate nucleus and surrounding areas of the rat hypothalamus. Brain Res 34P.233-242. 

Li S, Hisano S, Daikoku S (1993) Mutual synaptic associations between neurons containing neuropeptide Y and neurons containing enkephalin in the arcuate nucleus of the rat hypothalamus. Neuroendocrinology 57 306-313. 

Zhang R, Hisano S, Chikamori-Aoyama M, Daikoku S (1987) Synaptic association between enkephalin-containing axon terminals and proopiomelanocortin-containing neurons in the arcuate nucleus of the hypothalamus. Neurosci Letts 52 151-156. 

Serotonin. Serotonin central receptors appear to play a major role in glucose homeostasis. Experiments in obese mice have demonstrated that small doses of a classical serotonin agonist, metachlorophenylpiperazine (mCPP), markedly lower plasma insulin levels and increase insulin sensitivity, without affecting food intake, body weight or fat mass. The downstream target of the involved serotonin receptor appears to be melanocortin-4 receptors, in the arcuate nucleus of the hypothalamus. 

A major site of leptin receptors is in the hypothalamus (the arcuate nucleus). 

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