Hypothalamic substance P-containing neurons. Sex-dependent topographical differences and ultrastructural transformations associated with stages of the estrous cycle

Tsuruo, Yoshihiro; Hisano, Setsuji; Okamura, Yoshihiro; Tsukamoto, Nobuhiro; Daikoku, Shigeo

doi:10.1016/0006-8993(84)90439-6

Cited by 45 publications

(32 citation statements)

References 31 publications

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“…Enlarged GnRH cells are commonly observed during breeding or when GnRH production is believed to be high in birds [Foster et al, 1987;Goldsmith et al, 1989;Hahn and Ball, 1995;Parry et al, 1997;Cho et al, 1998;Deviche et al, 2000;MacDougall-Shackleton et al, 2001;Moore et al, 2006], mammals [Kawamoto et al, 2000], and fish [Davis and Fernald, 1990;Francis et al, 1992;White and Fernald, 1993]. Ultrastructural studies of neurons in mammals show increased endoplasmic reticulum and number of granulated vesicles associated with increased cell body size [King et al, 1974;Tsuruo et al, 1984;Rance et al, 1990] which is consistent with increased peptide production. Further, proGnRH mRNA (also referred to as GnRH mRNA) is higher in animals with larger GnRH-ir cell bodies [Kawamoto et al, 2000;White et al, 2002].…”

Section: Cgnrh-i and Prognrhmentioning

confidence: 74%

Photoperiod-Independent Hypothalamic Regulation of Luteinizing Hormone Secretion in a Free-Living Sonoran Desert Bird, the Rufous-Winged Sparrow <i>(Aimophila carpalis)</i>

et al. 2007

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We investigated the regulation of luteinizing hormone (LH) in the male Rufous-winged Sparrow,Aimophila carpalis, a resident of the Sonoran desert that breeds after irregular summer rains. Although the testes develop in March due to increasing photoperiod and regress in September due to decreasing photoperiod, LH does not consistently increase in the spring as in other photoperiodic birds. However, throughout the year increased plasma LH is correlated with rainfall. To investigate this rainfall-associated regulation of LH secretion, we quantified immunocytochemical labeling for gonadotropin-releasing hormone I (GnRH-I), proGnRH (the GnRH precursor), and gonadotropin-inhibitory hormone (GnIH) in the hypothalamus of free-living adult males caught before (low LH), and during (high LH) the monsoon rainy season. Compared to pre-monsoon birds, birds caught during the monsoon season had larger immunoreactive GnRH-I (GnRH-I-ir) and proGnRH-ir cell bodies, as well as fewer, less densely labeled proGnRH-ir cell bodies. Birds caught during the monsoon had fewer, less densely labeled GnIH-ir cell bodies than birds caught before the monsoon. Further, there was no GnIH-ir labeling in the median eminence on either capture dates, suggesting that GnIH is not released to the pituitary gland via the portal vein at this time of year, but there were fewer GnIH-ir fibers in the preoptic area of birds caught during the monsoon season. Our data support the hypothesis that environmental factors associated with increased rainfall during the monsoon season stimulate GnRH synthesis and release to increase LH secretion. These data also suggest that GnIH could inhibit GnRH neuronal activity prior to the monsoon season.

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Section: Cgnrh-i and Prognrhmentioning

confidence: 74%

Photoperiod-Independent Hypothalamic Regulation of Luteinizing Hormone Secretion in a Free-Living Sonoran Desert Bird, the Rufous-Winged Sparrow <i>(Aimophila carpalis)</i>

et al. 2007

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“…In the central nervous system, high con centrations of SP are found in the dorsal horn of the spinal cord, the nucleus of the descending tract of the trigeminal nerve, and various subcortical regions of the brain, includ ing the substantia nigra, amygdala, and hypothalamus [28]. Very recently, we demonstrated that, in the rat hypothala mus, the distribution of SP-containing neurons shows a sex difference [32,33], and that in females its cellular appear ance reflects periodical differences during the estrous cycle [32]. These facts suggested that SP may be involved in the hypothalamic-hypophysial-gonadal axis.…”

mentioning

confidence: 97%

“…They were supplied from the laboratory of Dr. H. Morishita (Department of Obstetrics and Gynecology, University of Toku shima. Japan), where they had been kept under a 12:12 h light-dark cycle [32], The animals were examined in proestrus, estrus and on the 2nd day of diestrus.…”

Section: Electron Microscopy: Animalsmentioning

confidence: 99%

Immunohistochemical Studies on the Roles of Substance P in the Rat Hypothalamus: Possible Implication in the Hypothalamic-Hypophysial-Gonadal Axis

Tsuruo¹,

Hisano²,

Nakanishi³

et al. 1987

Neuroendocrinology

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The hypothalamic neurons containing substance P (SP) were examined immunohistochemically in rats with a normal estrous cycle or persistent estrus (PE), in pregnancy and in lactating state. In PE animals, the neurons increased in number 1 week after ovariectomy, but then decreased and disappeared. During pregnancy, there were many SP neurons at an early stage but later they gradually decreased in number and disappeared. Consequently, during lactation no SP neurons were evident. The external layer of the median eminence (ME) contained many immunolabeled nerve terminals. In the ME prepared by a freeze-drying technique and immunostained with gold-labeled IgG by the postembedding procedure, the immunolabeled terminals were seen to contain large cored vesicles (50–100 nm) labeled with gold and unlabeled small clear vesicles (30–50 nm). In normal cycling rats, the terminals contained large cored vesicles in diestrus, small clear vesicles in estrus, and both in proestrus. In PE rats, the terminals contained only small clear vesicles, but the cored vesicles appeared after ovariectomy. In the early stage of pregnancy, the terminals contained only small clear vesicles, but the large cored vesicles appeared in late pregnancy and during lactation. These findings present further evidence that the hypothalamic SP neurons are involved in the hypothalamic-hypophysial-gonadal axis in rats.

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“…Because N K B and SP share a common Cterminal structure, significant cross-reactivity may exist between tachykinin antisera [23,51]. Therefore, it is pos sible that a previous finding of an increased number of arcuate 'SP-immunoreactive' neurons in proestrous com pared to diestrous rats reflected a contribution of N K B neurons due to immunologic cross-reactivity [41]. Al though the use of nuclease protection assays has demon strated estrogen regulation of SP m RNA in whole rat hypothalamus, the specific location of SP modulation by estrogens was not determined [52], Experimental treatment with a single injection of EV results in a supraphysiological sustained elevation of plas ma estradiol, persistent vaginal cornification, and in creased microglial and astrocytic activity in the arcuate nucleus [7,8].…”

mentioning

confidence: 98%

“…Two sections within the anterior arcuate nucleus were selected from each animal corresponding to plate 29 o f the Paxinos and Watson Rat Brain Atlas [40] which yielded a total o f four arcuate nucleus fields in each animal (n = 2/section). Because increased numbers o f SP neurons have been reported in the posterior arcuate [34,41], for the SP probe, two additional sections were analyzed corre sponding to plate 35 o f the Paxinos and Watson Rat Brain Atlas [40].…”

Section: Computer Microscopymentioning

confidence: 99%

Neurokinin B Gene Expression Is Increased in the Arcuate Nucleus of Ovariectomized Rats

1994

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Hypertrophy and increased gene expression of tachykinin neurons occur in the infundibular (arcuate) nucleus of postmenopausal women. We have hypothesized that the alterations in tachykinin gene expression in the hypothalami of postmenopausal women are secondary to ovarian failure and not due to age per se. In this study, in situ hybridization and computer-assisted microscopy were used to determine whether ovariectomy modulates neurokinin B (NKB), substance P (SP) or proopiomelanocortin (POMC) gene expression in the rat arcuate nucleus. Four groups were examined: proestrus; diestrous day 1; ovariectomized, and constant estrus induced by a single injection of 20 mg/kg estradiol valerate. Rats were sacrificed 2 months after treatment. Computer-assisted microscopy was used to determine the number of tachykinin neurons, cell areas, and the autoradiographic grain density of labeled neurons. We report marked changes in NKB gene expression in ovariectomized rats. The number of neurons containing NKB gene transcripts was significantly greater in ovariectomized rats (16.9 ± 1.0 neurons/arcuate section) than all other groups. There was also a significant difference in the number of NKB neurons/arcuate section between proestrous (8.9 ± 1.8 neurons) and diestrous (4.8 ± 1.0 neurons) rats. The lowest number of neurons was detected in the estradiol valerate-injected rats (2.9 ± 0.6 NKB neurons/ arcuate section). Furthermore, the autoradiographic grain density of NKB neurons was doubled in the ovariectomized group compared to all other groups. In contrast, few SP neurons were identified in the rat arcuate nucleus and no changes were detected during the estrous cycle or in response to ovariectomy. However, the mean cell area of SP neurons was decreased in the estradiol valerate rats. The only change detected in POMC arcuate neurons was a decreased number of cells in the estradiol valerate rat. These data indicate that NKB neurons in the rat arcuate nucleus are modulated by ovarian hormones and support the hypothesis that increased NKB gene expression in the hypothalamus of postmenopausal women is due to ovarian failure.

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Hypothalamic substance P-containing neurons. Sex-dependent topographical differences and ultrastructural transformations associated with stages of the estrous cycle

Cited by 45 publications

References 31 publications

Photoperiod-Independent Hypothalamic Regulation of Luteinizing Hormone Secretion in a Free-Living Sonoran Desert Bird, the Rufous-Winged Sparrow <i>(Aimophila carpalis)</i>

Photoperiod-Independent Hypothalamic Regulation of Luteinizing Hormone Secretion in a Free-Living Sonoran Desert Bird, the Rufous-Winged Sparrow <i>(Aimophila carpalis)</i>

Immunohistochemical Studies on the Roles of Substance P in the Rat Hypothalamus: Possible Implication in the Hypothalamic-Hypophysial-Gonadal Axis

Neurokinin B Gene Expression Is Increased in the Arcuate Nucleus of Ovariectomized Rats

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