Progesterone-Receptive β-Endorphin and Dynorphin B Neurons in the Arcuate Nucleus Project to Regions of High Gonadotropin-Releasing Hormone Neuron Density in the Ovine Preoptic Area

Dufourny, Laurence; Caraty, Alain; Clarke, I. J.; Robinson, Jane E.; Skinner, Donal C.

doi:10.1159/000086527

Cited by 36 publications

(31 citation statements)

References 111 publications

(89 reference statements)

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“…As previously reported by us and others [13, 26, 42], FG-labeled neurons were mainly detected ipsilateral to the injection site in several hypothalamic areas including the arcuate nucleus, ventrolateral and caudal aspects of the ventromedial nucleus, dorsomedial nucleus, median eminence and the periventricular hypothalamic and perifornical areas.…”

Section: Resultssupporting

confidence: 84%

“…As reported previously for these animals [13], of the 24 injected with FG, only 4 ewes had their injection site located in the OVLT/rostral preoptic area and encompassed at least 80 GnRH neurons (fig. 1).…”

Section: Resultsmentioning

confidence: 71%

“…The presence of triple-labeled neurons FG/PR/TH or FG/PR/NPY was determined using software (Adobe Photoshop 7.0, San Jose, Calif., USA), which enables two images taken from the same area to be superimposed. We have previously used this multiple photography approach to study steroid receptor colocalization in the same neurons [41] and FG/PR colocalization in opioidergic neurons [13]. For each animal, 36 pairs of photographs were taken at 20× magnification on 30 sections separated by 200 µm throughout the rostrocaudal extent of the arcuate nucleus.…”

Section: Methodsmentioning

confidence: 99%

“…We recently reported a notable projection of PR-containing neurons in the arcuate nucleus to GnRH-rich regions of the rostral preoptic area [13]. Moreover, we found that approximately a third of these PR-immunoreactive projecting neurons were immunoreactive for the opioids, dynorphin B and β-endorphin [13]. The identity of the remaining progesterone-receptive neurons is unknown.…”

Section: Introductionmentioning

confidence: 99%

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Progesterone-Receptive Dopaminergic and Neuropeptide Y Neurons Project from the Arcuate Nucleus to Gonadotropin-Releasing Hormone-Rich Regions of the Ovine Preoptic Area

Dufourny

Caraty

Clarke³

et al. 2005

Neuroendocrinology

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Progesterone inhibits gonadotropin-releasing hormone (GnRH) secretion in sheep through an interneuronal system located in the mediobasal hypothalamus. This study focused on known inhibitors of GnRH secretion in sheep, dopamine and neuropeptide Y (NPY). As the distributions of tyrosine hydroxylase (TH)- and NPY-immunoreactive neurons overlap with progesterone receptors (PR) in the arcuate nucleus, we hypothesized that, if these neurons mediate, at least partially, the inhibitory feedback signal of progesterone, then they should co-express PRs. Fluorogold (FG), a retrograde tracer, was injected into the preoptic area of ovariectomized ewes pretreated with estrogen and progesterone. When the FG injection site encompassed at least 80 GnRH neurons, sections from the arcuate nucleus were processed using dual immunocytochemistry for PR and either TH or NPY. We found that 30% of PR-immunoreactive, 12% of TH-containing and 21% of NPY-synthesizing neurons project toward this GnRH-rich region. Of the PR/TH dual-labeled cells, which represent 21% of PR and 31% of TH cells, respectively, 22% displayed FG labeling. Of the PR/NPY neurons, which account for 19% of PR and 67% of NPY neurons, respectively, 26% were FG fluorescent. This study suggests that subsets of arcuate nucleus dopaminergic and NPY neurons may transduce, at least in part, the progesterone-mediated inhibition of GnRH secretion.

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Section: Resultssupporting

confidence: 84%

Section: Resultsmentioning

confidence: 71%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Progesterone-Receptive Dopaminergic and Neuropeptide Y Neurons Project from the Arcuate Nucleus to Gonadotropin-Releasing Hormone-Rich Regions of the Ovine Preoptic Area

Dufourny

Caraty

Clarke³

et al. 2005

Neuroendocrinology

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“…These areas have also been found to express high levels of other neuropeptides, specifically other endogenous opioid peptides, and gonadal steroid receptors (estrogen and progesterone receptors) (33,34). Indeed, the location of OFQ-ir cells in the ovine arcuate nucleus is similar to that of dynorphin (35,36), neurokinin B (37), enkephalin (38), ␤-endorphin (36), dopamine (39), and neuropeptide Y (39). However, in preliminary studies, OFQ and dynorphin were not colocalized in the arcuate nucleus (Foradori, C. D., unpublished data) which, considering the high degree of colocalization between dynorphin and neurokinin B in this area (35), suggests that OFQ also does not colocalize with the latter neuropeptide.…”

Section: Discussionmentioning

confidence: 99%

Orphanin FQ: Evidence for a Role in the Control of the Reproductive Neuroendocrine System

et al. 2007

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Orphanin FQ (OFQ), also known as nociceptin, is a member of the endogenous opioid peptide family that has been functionally implicated in the control of pain, anxiety, circadian rhythms, and neuroendocrine function. In the reproductive system, endogenous opioid peptides are involved in the steroid feedback control of GnRH pulses and the induction of the GnRH surge. The distribution of OFQ in the preoptic area and hypothalamus overlaps with GnRH, and in vitro evidence suggests that OFQ can inhibit GnRH secretion from hypothalamic fragments. Using the sheep as a model, we examined the potential anatomical colocalization between OFQ and GnRH using dual-label immunocytochemistry. Confocal microscopy revealed that approximately 93% of GnRH neurons, evenly distributed across brain regions, were also immunoreactive for OFQ. In addition, almost all GnRH fibers and terminals in the external zone of the median eminence, the site of neurosecretory release of GnRH, also colocalized OFQ. This high degree of colocalization suggested that OFQ might be functionally important in controlling reproductive endocrine events. O RPHANIN FQ (OFQ), also known as nociceptin, is a member of the family of endogenous opioid peptides, which also includes ␤-endorphin, enkephalins, and dynorphin (1). Whereas sharing some homology with dynorphin, OFQ does not exhibit appreciable binding affinity for classical opioid receptors (1, 2); rather it functions as an endogenous ligand for the opioid receptor like (ORL)-1 receptor (1). OFQ cells are present in the preoptic area, anterior hypothalamus, and arcuate nucleus of the hypothalamus of the rat (3) and human (4). Functionally, OFQ has been implicated in a variety of systems including pain (5), anxiety (6), cardiovascular function (7), food intake (8), circadian rhythms (9), and cognition (10). There is also evidence that OFQ may play a role in neuroendocrine function: intracerebroventricular delivery of OFQ in the rat stimulates GH and prolactin (11, 12) and has been reported to both stimulate (13) and inhibit (14) corticosterone secretion. Sinchak et al. (15) have shown that OFQ delivered into the ventromedial nucleus facilitates lordosis in female rats in a dose-dependent manner. However, there has been relatively little attention to the possible role of OFQ in reproductive neuroendocrine function, specifically in the control of GnRH secretion.GnRH neurons, and their projections to the median eminence, control the secretion of pituitary LH and thus comprise the final common pathway for the neuroendocrine control of reproduction (16). Endogenous opioid peptides are important regulators of the GnRH system, controlling both the preovulatory surge (17) and pulsatile secretion (18) of GnRH. OFQ has been shown to inhibit forskolin-induced GnRH secretion in a dose-dependent manner from rat hypothalamic fragments (19). OFQ cells in the preoptic area and anterior hypothalamus overlap the site of a majority of GnRH perikarya (20 -22). In addition, OFQ fibers and ORL-1 receptors are present in high abund...

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Gonadotropins and Progestogens: Obligatory Developmental Functions during Early Embryogenesis and their Role in Adult Neurogenesis, Neuroregeneration and Neurodegeneration

Atwood

Meethal

2011

Hormones in Neurodegeneration, Neuroprotection, and Neurogenesis

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IntroductionHormones of the hypothalamic-pituitary-gonadal (HPG) axis are well known for their roles in reproduction. However, sex hormones have roles far beyond the regulation and coordination of reproduction; they also control the entire molecular process of life from the conception of the embryo through its development into an adult and finally its demise during senescence [1]. This recent understanding of the ''big picture,'' that is, of how HPG hormones regulate life processes, has gathered support from studies identifying the function of reproductive hormones in embryonic development [2][3][4][5], as well as from studies into the extrareproductive functions of HPG hormones in the postreproductive physiology of mammals (reviewed in [6]).This chapter describes our current, albeit incomprehensively small, knowledge of how reproductive (pregnancy) hormones direct growth and development during embryogenesis. It also describes the requirement for these reproductive hormones during adult life, and how the age-related dysregulation in the signaling of these hormones drives neurodegeneration and cognitive decline during senescence. Hormonal Regulation of Human Embryogenesis The Missing LinksEmbryogenesis is a complex coordinated series of molecular and cellular changes that takes place within a well-defined internal environment. Human embryogenesis is orchestrated by a complex array of endocrine signals that commences with conception, is followed by the growth and development of the zygote into a blastocyst, its implantation into the endometrium, and the subsequent growth and development of the blastocyst into the neonate. Following conception, the Hormones in Neurodegeneration, Neuroprotection, and Neurogenesis.

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Progesterone-Receptive β-Endorphin and Dynorphin B Neurons in the Arcuate Nucleus Project to Regions of High Gonadotropin-Releasing Hormone Neuron Density in the Ovine Preoptic Area

Cited by 36 publications

References 111 publications

Progesterone-Receptive Dopaminergic and Neuropeptide Y Neurons Project from the Arcuate Nucleus to Gonadotropin-Releasing Hormone-Rich Regions of the Ovine Preoptic Area

Progesterone-Receptive Dopaminergic and Neuropeptide Y Neurons Project from the Arcuate Nucleus to Gonadotropin-Releasing Hormone-Rich Regions of the Ovine Preoptic Area

Orphanin FQ: Evidence for a Role in the Control of the Reproductive Neuroendocrine System

Gonadotropins and Progestogens: Obligatory Developmental Functions during Early Embryogenesis and their Role in Adult Neurogenesis, Neuroregeneration and Neurodegeneration

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