60 YEARS OF NEUROENDOCRINOLOGY: The structure of the neuroendocrine hypothalamus: the neuroanatomical legacy of Geoffrey Harris

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   Figure 1

   Six maps from 1955 to 2009 showing the hypothalamic locations of regions that contain neuroendocrine neurons and pituitary hormone control mechanisms. They illustrate the dramatic improvement in the resolution of these representations over time. (A) Diagram of a midline sagittal section through the hypothalamus and pituitary gland. The stippled areas indicate the sites where electrical stimulation or lesions resulted in changes of pituitary secretion. ACTH, adrenocorticotrophic hormone; DMH, dorsomedial nucleus of the hypothalamus; LH, luteinizing hormone; MN, mammillary nuclei; PN, posterior nucleus; PVH, paraventricular nucleus of the hypothalamus; TSH, thyroid-stimulating hormone; VMH, ventromedial nucleus of the hypothalamus; OC, optic chiasm; SON, supraoptic nucleus. Reproduced, with permission, from Harris GW (1955b) The function of the pituitary stalk. Bulletin of the Johns Hopkins Hospital 97 p370, Figure 2. Reprinted with permission of Johns Hopkins University Press. (B) The hypophysiotropic area of the hypothalamus. The solid black line represents the borders of five relatively midline pituitary grafts in which considerable cellular integrity was maintained despite their ectopic site. The dotted circles are the locations of periodic acid-Schiff-positive basophils. AHN, anterior hypothalamic area; AHyp, adenohypophysis; ARH, arcuate nucleus; PM, premammillary nucleus; PP, posterior pituitary; SCH, suprachiasmatic nucleus. Adapted, with permission, from Halasz B, Pupp L & Uhlarik S (1962) Hypophysiotrophic area in the hypothalamus. Journal of Endocrinology 25 147–154. (C) Similar to (A), except both stippling and cross-hatching are used to indicate the sites where electrical stimulation or lesions resulted in changes of pituitary secretion. Reproduced, with permission, from Harris GW (1972) Humours and hormones. Journal of Endocrinology 53 ii–xxiii. (D) General diagram of the system of LRF (GnRH)-producing cells in a paramedian sagittal section of guinea pig hypothalamus. The red dots show specifically immunoreactive perikarya. The dotted lines show the pathway of LRF axons (the arrows showing direction of transport). AC, anterior commissure; MM, median mammillary nucleus. Reproduced, with permission, from Barry J, Dubois MP & Poulain P (1973) LRF producing cells of themammalian hypothalamus. A fluorescent antibody study. Zeitschrift fur Zellforschung und Mikroskopische Anatomie 146 351–366. Copyright 1973 Springer-Verlag.
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   Figure 2

   Brightfield photomicrographs of hybridization for CRH mRNA (A) and CRH hnRNA (B) on sections counterstained with thionin to show cell nuclei. Note the cytoplasmic labeling for the mRNA and the nuclear labeling for the hnRNA (scale bar=5 μm). (C) A schematic representation of the rat pre-procorticotropin-releasing hormone (ppCRH) gene. It shows the location of exon 1, the intronic sequence, exon 2, the cyclic AMP response element (CRE), and the TATA-core promoter sequence (TATA-A). Also shown are coding regions for the ppCRH translated sequence (black box) and the CRH amino acid (aa′) sequence (red box). The black dashed and solid lines at the bottom of the diagram show the sequences that are targeted by a 760 bp cRNA probe for ppCRH mRNA and a 536 bp cRNA probe for ppCRH hnRNA that detects the primary transcribed (intronic) sequence. Reproduced, with permission, from Tanimura SM, Sanchez-Watts G & Watts AG (1998) Peptide gene activation, secretion, and steroid feedback during stimulation of rat neuroendocrine corticotropin-releasing hormone neurons. Endocrinology 139 3822–3829. Copyright 1998 The Endocrine Society.
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   Figure 3

   Anatomical distribution and CRH protein expression in tdTomato-labeled cells in the paraventricular nucleus of the hypothalamus (PVH) of Crh-IRES-Cre;Ai14 mice. (A) Confocal image (20× magnification) of the PVH in a Crh-IRES-Cre;Ai14 (tdTomato, red) mouse (level 61 of Dong (2007)). (B) Confocal image (40×) of a colchicine-treated Crh-IRES-Cre;Ai14 mouse PVN. Immunostaining for corticotropin-releasing hormone (CRH) is shown in green. (B′) Higher magnification (100×) of the box inset in (B). Confocal images of the PVH in Crh-IRES-Cre;Ai14 (tdTomato, red) mouse labeled for vGluT2 (C, green), or vGAT (D, green). Note the numerous close appositions (yellow) between tdTomato (CRH) neurons and glutamaterigic (vGlutT2) and GABAergic (vGAT) elements. (E) Bar graph showing the percentage of tdTomato-positive cells that co-express various neuropeptides in five colchicine-treated mice. CRH, corticotropin-releasing hormone; FG, fluorogold; OT, oxytocin; SST, somatostatin; TRH, thyrotropin-releasing hormone. (F) Confocal images (60× magnification) from three mouse PVH sections (F, F′, and F″) showing the morphology of single tdTomato neurons (red) filled with Alexa488 (green) and biocytin (yellow) during whole-cell patch clamp recordings. Scale bars are 100 μm (A), 50 μm (B, F, F′, and F″), and 20 μm (B′, C, and D). (A, B, E, and F) reproduced from Wamsteeker Cusulin JI, Füzesi T, Watts AG & Bains JS (2013) Characterization of corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus of Crh-IRES-Cre mutant mice. PLoS ONE 8 e64943. Published under the Creative Commons Attribution (CC BY) license. (C and D) Unpublished photomicrographs from the author's laboratory (CS Johnson & AG Watts).
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   Figure 4

   (A, B, and C) Three maps of the rat PVH taken from a reference atlas of neuroendocrine neuron type labeled with antibodies for neuropeptides. The locations of each type of peptidergic neuroendocrine neuron are plotted onto three levels of PVH (designated by the number at the bottom of each panel) (data from Swanson 2003, Simmons & Swanson 2009). (D, E, and F) Schematic drawings illustrating the delineations of three levels of the PVH in the mouse brain, which were determined based on the distributions of eight neuronal phenotypes in two major neuroendocrine divisions (magnocellular (m) PVHm, including OXY and VAS; and parvicellular (p) PVHp, including CRH, SS, and TRH) and three descending preautonomic populations (PVHd) that project to the intermediolateral column of the spinal cord (IML-d), to the central gray of the spinal cord (CGS-d), and to the dorsal motor nucleus of the vagus nerve (DMX-d). The mouse atlas levels (Dong 2007) are designated by the number at the bottom of each panel. Reproduced, with permission, from Biag J, Huang Y, Gou L, Hintiryan H, Askarinam A, Hahn JD, Toga AW & Dong HW (2012) Cyto- and chemoarchitecture of the hypothalamic paraventricular nucleus in the C57BL/6J male mouse: a study of immunostaining and multiple fluorescent tract tracing. Journal of Comparative Neurology 520 6–33. Copyright 2011 Wiley Periodicals, Inc. 3V, third ventricle; AHN, anterior hypothalamic nucleus; CRH, corticotropin-releasing hormone; DP, dorsal parvicellular part of the PVH (descending division); GRH, growth hormone-releasing hormone; MNE, magnocellular neuroendocrine; MPD, medial parvicellular part of the PVH, dorsal zone; MPV, medial parvicellular part of the PVH, ventral zone; OXY, oxytocin; PML, posterior magnocellular part of the PVH, lateral zone; PMM, posterior magnocellular part of the PVH, medial zone; PNE, parvicellular neuroendocrine; PV, periventricular part of the PVH; SS, somatostatin; TRH, thyrotropin-releasing hormone; VAS, vasopressin.

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