1
|
Panda SP, Kesharwani A, Singh GD, Prasanth D, Vatchavai BR, Kumari PVK, Panda SK, Mallick SP. Impose of KNDy/GnRH neural circuit in PCOS, ageing, cancer and Alzheimer's disease: StAR actions in prevention of neuroendocrine dysfunction. Ageing Res Rev 2023; 92:102086. [PMID: 37821047 DOI: 10.1016/j.arr.2023.102086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/06/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023]
Abstract
The Kisspeptin1 (KISS1)/neurokinin B (NKB)/Dynorphin (Dyn) [KNDy] neurons in the hypothalamus regulate the reproduction stage in human beings and rodents. KNDy neurons co-expressed all KISS1, NKB, and Dyn peptides, and hence commonly regarded as KISS1 neurons. KNDy neurons contribute to the "GnRH pulse generator" and are implicated in the regulation of pulsatile GnRH release. The estradiol (E2)-estrogen receptor (ER) interactions over GnRH neurons in the hypothalamus cause nitric oxide (NO) discharge, in addition to presynaptic GABA and glutamate discharge from respective neurons. The released GABA and glutamate facilitate the activity of GnRH neurons via GABAA-R and AMPA/kainate-R. The KISS1 stimulates MAPK/ERK1/2 signaling and cause the release of Ca2+ from intracellular store, which contribute to neuroendocrine function, increase apoptosis and decrease cell proliferation and metastasis. The ageing in women deteriorates KISS1/KISS1R interaction in the hypothalamus which causes lower levels of GnRH. Because examining the human brain is so challenging, decades of clinical research have failed to find the causes of KNDy/GnRH dysfunction. The KISS1/KISS1R interactions in the brain have a neuroprotective effect against Alzheimer's disease (AD). These findings modulate the pathophysiological role of the KNDy/GnRH neural network in polycystic ovarian syndrome (PCOS) associated with ageing and, its protective role in cancer and AD. This review concludes with protecting effect of the steroid-derived acute regulatory enzyme (StAR) against neurotoxicity in the hippocampus, and hypothalamus, and these measures are fundamental for delaying ageing with PCOS. StAR could serve as novel diagnostic marker and therapeutic target for the most prevalent hormone-sensitive breast cancers (BCs).
Collapse
Affiliation(s)
- Siva Prasad Panda
- Institute of Pharmaceutical Research, GLA University, Mathura, Uttar Pradesh, India.
| | - Adarsh Kesharwani
- Institute of Pharmaceutical Research, GLA University, Mathura, Uttar Pradesh, India
| | | | - Dsnbk Prasanth
- KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada, Andhrapradesh, India
| | - Bhaskara Raju Vatchavai
- Sri Vasavi Institute of Pharmaceutical Sciences, Pedatadepalli, Tadepalligudem, Andhrapradesh, India
| | - P V Kamala Kumari
- Vignan Institute of Pharmaceutical Technology, Duvvada, Visakhapatnam, Andhrapradesh, India
| | | | | |
Collapse
|
2
|
Buo C, Bearss RJ, Novak AG, Anello AE, Dakin JJ, Piet R. Serotonin stimulates female preoptic area kisspeptin neurons via activation of type 2 serotonin receptors in mice. Front Endocrinol (Lausanne) 2023; 14:1212854. [PMID: 37900129 PMCID: PMC10602649 DOI: 10.3389/fendo.2023.1212854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/19/2023] [Indexed: 10/31/2023] Open
Abstract
Background The neuroendocrine control of ovulation is orchestrated by neuronal circuits that ultimately drive the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus to trigger the preovulatory surge in luteinizing hormone (LH) secretion. While estrogen feedback signals are determinant in triggering activation of GnRH neurons, through stimulation of afferent kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3VKISS1 neurons), many neuropeptidergic and classical neurotransmitter systems have been shown to regulate the LH surge. Among these, several lines of evidence indicate that the monoamine neurotransmitter serotonin (5-HT) has an excitatory, permissive, influence over the generation of the surge, via activation of type 2 5-HT (5-HT2) receptors. The mechanisms through which this occurs, however, are not well understood. We hypothesized that 5-HT exerts its influence on the surge by stimulating RP3VKISS1 neurons in a 5-HT2 receptor-dependent manner. Methods We tested this using kisspeptin neuron-specific calcium imaging and electrophysiology in brain slices obtained from male and female mice. Results We show that exogenous 5-HT reversibly increases the activity of the majority of RP3VKISS1 neurons. This effect is more prominent in females than in males, is likely mediated directly at RP3VKISS1 neurons and requires activation of 5-HT2 receptors. The functional impact of 5-HT on RP3VKISS1 neurons, however, does not significantly vary during the estrous cycle. Conclusion Taken together, these data suggest that 5-HT2 receptor-mediated stimulation of RP3VKISS1 neuron activity might be involved in mediating the influence of 5-HT on the preovulatory LH surge.
Collapse
Affiliation(s)
- Carrie Buo
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Robin J. Bearss
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Alyssa G. Novak
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Anna E. Anello
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Jordan J. Dakin
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Richard Piet
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| |
Collapse
|
3
|
Mansano NDS, Vieira HR, Araujo-Lopes R, Szawka RE, Donato J, Frazao R. Fasting Modulates GABAergic Synaptic Transmission to Arcuate Kisspeptin Neurons in Female Mice. Endocrinology 2023; 164:bqad150. [PMID: 37793082 DOI: 10.1210/endocr/bqad150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/28/2023] [Accepted: 10/02/2023] [Indexed: 10/06/2023]
Abstract
It is well-established that the hypothalamic-pituitary-gonadal (HPG) axis is suppressed due to negative energy balance. However, less information is available on whether kisspeptin neuronal activity contributes to fasting-induced responses. In the present study, female and male mice were fasted for 24 hours or provided food ad libitum (fed group) to determine whether acute fasting is sufficient to modulate kisspeptin neuronal activity. In female mice, fasting attenuated luteinizing hormone (LH) and prolactin (PRL) serum levels and increased follicle-stimulating hormone levels compared with the fed group. In contrast, fasting did not affect gonadotropin or PRL secretion in male mice. By measuring genes related to LH pulse generation in micropunches obtained from the arcuate nucleus of the hypothalamus (ARH), we observed that fasting reduced Kiss1 mRNA levels in female and male mice. In contrast, Pdyn expression was upregulated only in fasted female mice, whereas no changes in the Tac2 mRNA levels were observed in both sexes. Interestingly, the frequency and amplitude of the GABAergic postsynaptic currents recorded from ARH kisspeptin neurons (ARHKisspeptin) were reduced in 24-hour fasted female mice but not in males. Additionally, neuropeptide Y induced a hyperpolarization in the resting membrane potential of ARHKisspeptin neurons of fed female mice but not in males. Thus, the response of ARHKisspeptin neurons to fasting is sexually dependent with a female bias, associated with changes in gonadotropins and PRL secretion. Our findings suggest that GABAergic transmission to ARHKisspeptin neurons modulates the activity of the HPG axis during situations of negative energy balance.
Collapse
Affiliation(s)
- Naira da Silva Mansano
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, São Paulo, SP 05508-000, Brazil
| | - Henrique Rodrigues Vieira
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, São Paulo, SP 05508-000, Brazil
| | - Roberta Araujo-Lopes
- Universidade Federal de Minas Gerais, Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Belo Horizonte, MG 31270-901, Brazil
| | - Raphael Escorsim Szawka
- Universidade Federal de Minas Gerais, Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Belo Horizonte, MG 31270-901, Brazil
| | - Jose Donato
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofísica, São Paulo, SP 05508-000, Brazil
| | - Renata Frazao
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, São Paulo, SP 05508-000, Brazil
| |
Collapse
|
4
|
Nestor CC, Merkley CM, Lehman MN, Hileman SM, Goodman RL. KNDy neurons as the GnRH pulse generator: Recent studies in ruminants. Peptides 2023; 164:171005. [PMID: 36990389 PMCID: PMC10164117 DOI: 10.1016/j.peptides.2023.171005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/10/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
This review considers three aspects of recent work on the role of KNDy neurons in GnRH pulse generation in ruminants. First, work on basic mechanisms of pulse generation includes several tests of this hypothesis, all of which support it, and evidence that Kiss1r-containing neurons form a positive feedback circuit with the KNDy neural network that strengthen the activity of this network. The second section on pathways mediating external inputs focuses on the influence of nutrition and photoperiod, and describes the evidence supporting roles for proopiomelanocortin (POMC) and agouti-related peptide (AgRP) afferents to KNDy cells in each of these. Finally, we review studies exploring the potential applications of manipulating signaling by kisspeptin, and the other KNDy peptides, to control reproductive function in domestic animals and conclude that, although these approaches show some promise, they do not have major advantages over current practices at this time.
Collapse
Affiliation(s)
- Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | | | - Michael N Lehman
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Stanley M Hileman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA
| | - Robert L Goodman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA.
| |
Collapse
|
5
|
Piet R. Circadian and kisspeptin regulation of the preovulatory surge. Peptides 2023; 163:170981. [PMID: 36842628 DOI: 10.1016/j.peptides.2023.170981] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/19/2023] [Accepted: 02/23/2023] [Indexed: 02/28/2023]
Abstract
Fertility in mammals is ultimately controlled by a small population of neurons - the gonadotropin-releasing hormone (GnRH) neurons - located in the ventral forebrain. GnRH neurons control gonadal function through the release of GnRH, which in turn stimulates the secretion of the anterior pituitary gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In spontaneous ovulators, ovarian follicle maturation eventually stimulates, via sex steroid feedback, the mid-cycle surge in GnRH and LH secretion that causes ovulation. The GnRH/LH surge is initiated in many species just before the onset of activity through processes controlled by the central circadian clock, ensuring that the neuroendocrine control of ovulation and sex behavior are coordinated. This review aims to give an overview of anatomical and functional studies that collectively reveal some of the mechanisms through which the central circadian clock regulates GnRH neurons and their afferent circuits to drive the preovulatory surge.
Collapse
Affiliation(s)
- Richard Piet
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, United States.
| |
Collapse
|
6
|
Campideli-Santana AC, Gusmao DO, Almeida FRCL, Araujo-Lopes R, Szawka RE. Partial loss of arcuate kisspeptin neurons in female rats stimulates luteinizing hormone and decreases prolactin secretion induced by estradiol. J Neuroendocrinol 2022; 34:e13204. [PMID: 36319592 DOI: 10.1111/jne.13204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/25/2022] [Accepted: 09/30/2022] [Indexed: 11/28/2022]
Abstract
Kisspeptin, neurokinin, and dynorphin (KNDy) neurons in the arcuate nucleus (ARC) control luteinizing hormone (LH) and prolactin (PRL) release, although their role in conveying the effects of estradiol (E2 ) to these hormones is not well understood. We performed a longitudinal evaluation of female rats in which KNDy neurons were ablated using a neurokinin-3 receptor agonist conjugated with saporin (NK3-SAP) to investigate the impact of the reduction of KNDy neurons on the E2 regulation of gonadal and PRL axes. NK3-SAP rats, bearing a moderate loss of ARC kisspeptin-immunoreactive (-IR) neurons (50%-90%), displayed irregular estrous cycles but essentially unaltered follicular development and a normal number of corpora lutea. Rats were then ovariectomized (OVX) and treated with a positive-feedback dose of E2 (OVX + E2 ). LH and PRL were measured in the tail blood by an enzyme-linked immunosorbent assay. The E2 -induced LH surge was amplified, whereas the PRL rise was decreased in NK3-SAP rats compared to Blank-SAP control. After 10 days of no hormonal treatment, basal LH levels were equally elevated in NK3-SAP and controls. Tyrosine hydroxylase (TH) phosphorylation in the median eminence, in turn, was increased in NK3-SAP rats, with no change in the number of ARC TH-IR neurons. Thus, KNDy neurons exert concurrent and opposite roles in the E2 -induced surges of LH and PRL. The partial loss of KNDy neurons disrupts ovarian cyclicity but does not preclude ovulation, consistent with the disinhibition of the LH preovulatory surge. Conversely, KNDy neurons tonically inhibit the enzymatic activity of tuberoinfundibular dopaminergic neurons, which appears to facilitate PRL release in response to E2 .
Collapse
Affiliation(s)
- Ana C Campideli-Santana
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniela O Gusmao
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Fernanda R C L Almeida
- Departamento de Morfologia, Instituto de Ciencias Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Roberta Araujo-Lopes
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Raphael E Szawka
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
7
|
Coutinho EA, Esparza LA, Hudson AD, Rizo N, Steffen P, Kauffman AS. Conditional Deletion of KOR (Oprk1) in Kisspeptin Cells Does Not Alter LH Pulses, Puberty, or Fertility in Mice. Endocrinology 2022; 163:6763672. [PMID: 36260530 DOI: 10.1210/endocr/bqac175] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Indexed: 01/26/2023]
Abstract
Classic pharmacological studies suggested that endogenous dynorphin-KOR signaling is important for reproductive neuroendocrine regulation. With the seminal discovery of an interconnected network of hypothalamic arcuate neurons co-expressing kisspeptin, neurokinin B, and dynorphin (KNDy neurons), the KNDy hypothesis was developed to explain how gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) pulses are generated. Key to this hypothesis is dynorphin released from KNDy neurons acting in a paracrine manner on other KNDy neurons via kappa opioid receptor (KOR) signaling to terminate neural "pulse" events. While in vitro evidence supports this aspect of the KNDy hypothesis, a direct in vivo test of the necessity of KOR signaling in kisspeptin neurons for proper LH secretion has been lacking. We therefore conditionally knocked out KOR selectively from kisspeptin neurons of male and female mice and tested numerous reproductive measures, including in vivo LH pulse secretion. Surprisingly, despite validating successful knockout of KOR in kisspeptin neurons, we found no significant effect of kisspeptin cell-specific deletion of KOR on any measure of puberty, LH pulse parameters, LH surges, follicle-stimulating hormone (FSH) levels, estrous cycles, or fertility. These outcomes suggest that the KNDy hypothesis, while sufficient normally, may not be the only neural mechanism for sculpting GnRH and LH pulses, supported by recent findings in humans and mice. Thus, besides normally acting via KOR in KNDy neurons, endogenous dynorphin and other opioids may, under some conditions, regulate LH and FSH secretion via KOR in non-kisspeptin cells or perhaps via non-KOR pathways. The current models for GnRH and LH pulse generation should be expanded to consider such alternate mechanisms.
Collapse
Affiliation(s)
- Eulalia A Coutinho
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Lourdes A Esparza
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Alexandra D Hudson
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Nathanael Rizo
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Paige Steffen
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Alexander S Kauffman
- Department of OBGYN and Reproductive Sciences, University of California San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
8
|
Moeller JS, Bever SR, Finn SL, Phumsatitpong C, Browne MF, Kriegsfeld LJ. Circadian Regulation of Hormonal Timing and the Pathophysiology of Circadian Dysregulation. Compr Physiol 2022; 12:4185-4214. [PMID: 36073751 DOI: 10.1002/cphy.c220018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Circadian rhythms are endogenously generated, daily patterns of behavior and physiology that are essential for optimal health and disease prevention. Disruptions to circadian timing are associated with a host of maladies, including metabolic disease and obesity, diabetes, heart disease, cancer, and mental health disturbances. The circadian timing system is hierarchically organized, with a master circadian clock located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus and subordinate clocks throughout the CNS and periphery. The SCN receives light information via a direct retinal pathway, synchronizing the master clock to environmental time. At the cellular level, circadian rhythms are ubiquitous, with rhythms generated by interlocking, autoregulatory transcription-translation feedback loops. At the level of the SCN, tight cellular coupling maintains rhythms even in the absence of environmental input. The SCN, in turn, communicates timing information via the autonomic nervous system and hormonal signaling. This signaling couples individual cellular oscillators at the tissue level in extra-SCN brain loci and the periphery and synchronizes subordinate clocks to external time. In the modern world, circadian disruption is widespread due to limited exposure to sunlight during the day, exposure to artificial light at night, and widespread use of light-emitting electronic devices, likely contributing to an increase in the prevalence, and the progression, of a host of disease states. The present overview focuses on the circadian control of endocrine secretions, the significance of rhythms within key endocrine axes for typical, homeostatic functioning, and implications for health and disease when dysregulated. © 2022 American Physiological Society. Compr Physiol 12: 1-30, 2022.
Collapse
Affiliation(s)
- Jacob S Moeller
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA
| | - Savannah R Bever
- Department of Psychology, University of California, Berkeley, California, USA
| | - Samantha L Finn
- Department of Psychology, University of California, Berkeley, California, USA
| | | | - Madison F Browne
- Department of Psychology, University of California, Berkeley, California, USA
| | - Lance J Kriegsfeld
- Graduate Group in Endocrinology, University of California, Berkeley, California, USA.,Department of Psychology, University of California, Berkeley, California, USA.,Department of Integrative Biology, University of California, Berkeley, California, USA.,The Helen Wills Neuroscience Institute, University of California, Berkeley, California, USA
| |
Collapse
|
9
|
Kauffman AS. Neuroendocrine mechanisms underlying estrogen positive feedback and the LH surge. Front Neurosci 2022; 16:953252. [PMID: 35968365 PMCID: PMC9364933 DOI: 10.3389/fnins.2022.953252] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/08/2022] [Indexed: 01/26/2023] Open
Abstract
A fundamental principle in reproductive neuroendocrinology is sex steroid feedback: steroid hormones secreted by the gonads circulate back to the brain to regulate the neural circuits governing the reproductive neuroendocrine axis. These regulatory feedback loops ultimately act to modulate gonadotropin-releasing hormone (GnRH) secretion, thereby affecting gonadotropin secretion from the anterior pituitary. In females, rising estradiol (E2) during the middle of the menstrual (or estrous) cycle paradoxically "switch" from being inhibitory on GnRH secretion ("negative feedback") to stimulating GnRH release ("positive feedback"), resulting in a surge in GnRH secretion and a downstream LH surge that triggers ovulation. While upstream neural afferents of GnRH neurons, including kisspeptin neurons in the rostral hypothalamus, are proposed as critical loci of E2 feedback action, the underlying mechanisms governing the shift between E2 negative and positive feedback are still poorly understood. Indeed, the precise cell targets, neural signaling factors and receptors, hormonal pathways, and molecular mechanisms by which ovarian-derived E2 indirectly stimulates GnRH surge secretion remain incompletely known. In many species, there is also a circadian component to the LH surge, restricting its occurrence to specific times of day, but how the circadian clock interacts with endocrine signals to ultimately time LH surge generation also remains a major gap in knowledge. Here, we focus on classic and recent data from rodent models and discuss the consensus knowledge of the neural players, including kisspeptin, the suprachiasmatic nucleus, and glia, as well as endocrine players, including estradiol and progesterone, in the complex regulation and generation of E2-induced LH surges in females.
Collapse
|
10
|
Jamieson BB, Piet R. Kisspeptin neuron electrophysiology: Intrinsic properties, hormonal modulation, and regulation of homeostatic circuits. Front Neuroendocrinol 2022; 66:101006. [PMID: 35640722 DOI: 10.1016/j.yfrne.2022.101006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 11/04/2022]
Abstract
The obligatory role of kisspeptin (KISS1) and its receptor (KISS1R) in regulating the hypothalamic-pituitary-gonadal axis, puberty and fertility was uncovered in 2003. In the few years that followed, an impressive body of work undertaken in many species established that neurons producing kisspeptin orchestrate gonadotropin-releasing hormone (GnRH) neuron activity and subsequent GnRH and gonadotropin hormone secretory patterns, through kisspeptin-KISS1R signaling, and mediate many aspects of gonadal steroid hormone feedback regulation of GnRH neurons. Here, we review knowledge accrued over the past decade, mainly in genetically modified mouse models, of the electrophysiological properties of kisspeptin neurons and their regulation by hormonal feedback. We also discuss recent progress in our understanding of the role of these cells within neuronal circuits that control GnRH neuron activity and GnRH secretion, energy balance and, potentially, other homeostatic and reproductive functions.
Collapse
Affiliation(s)
| | - Richard Piet
- Brain Health Research Institute and Department of Biological Sciences, Kent State University, Kent, OH, USA.
| |
Collapse
|
11
|
Goodman RL, Herbison AE, Lehman MN, Navarro VM. Neuroendocrine control of gonadotropin-releasing hormone: Pulsatile and surge modes of secretion. J Neuroendocrinol 2022; 34:e13094. [PMID: 35107859 PMCID: PMC9948945 DOI: 10.1111/jne.13094] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
The concept that different systems control episodic and surge secretion of gonadotropin-releasing hormone (GnRH) was well established by the time that GnRH was identified and formed the framework for studies of the physiological roles of GnRH, and later kisspeptin. Here, we focus on recent studies identifying the neural mechanisms underlying these two modes of secretion, with an emphasis on their core components. There is now compelling data that kisspeptin neurons in the arcuate nucleus that also contain neurokinin B (NKB) and dynorphin (i.e., KNDy cells) and their projections to GnRH dendrons constitute the GnRH pulse generator in mice and rats. There is also strong evidence for a similar role for KNDy neurons in sheep and goats, and weaker data in monkeys and humans. However, whether KNDy neurons act on GnRH dendrons and/or GnRH soma and dendrites that are found in the mediobasal hypothalamus (MBH) of these species remains unclear. The core components of the GnRH/luteinising hormone surge consist of an endocrine signal that initiates the process and a neural trigger that drives GnRH secretion during the surge. In all spontaneous ovulators, the core endocrine signal is a rise in estradiol secretion from the maturing follicle(s), with the site of estrogen positive feedback being the rostral periventricular kisspeptin neurons in rodents and neurons in the MBH of sheep and primates. There is considerable species variations in the neural trigger, with three major classes. First, in reflex ovulators, this trigger is initiated by coitus and carried to the hypothalamus by neural or vascular pathways. Second, in rodents, there is a time of day signal that originates in the suprachiasmatic nucleus and activates rostral periventricular kisspeptin neurons and GnRH soma and dendrites. Finally, in sheep nitric oxide-producing neurons in the ventromedial nucleus, KNDy neurons and rostral kisspeptin neurons all appear to participate in driving GnRH release during the surge.
Collapse
Affiliation(s)
- Robert L. Goodman
- Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV, USA
| | - Allan E. Herbison
- Department of Physiology Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Michael N. Lehman
- Brain Health Research Institute, Kent State University, Kent, OH, USA
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Victor M. Navarro
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School and Department of Medicine, Boston, MA, USA
| |
Collapse
|
12
|
Raúl Schmidt A, Ignacio Felipe Inserra P, Andrés Cortasa S, Proietto S, Fidel V, Halperin J, Daniel Vitullo A, Berta Dorfman V. Distribution of kisspeptin system and its relation with gonadotropin-releasing hormone in the hypothalamus of the South American plains vizcacha, Lagostomus maximus. Gen Comp Endocrinol 2022; 317:113974. [PMID: 34973969 DOI: 10.1016/j.ygcen.2021.113974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 12/21/2021] [Accepted: 12/26/2021] [Indexed: 11/20/2022]
Abstract
Kisspeptin (KISS), a key hormone involved in the regulation of the hypothalamic-pituitary-ovarian (HPO) axis, has been localized in the anteroventral periventricular (AVPV) nucleus and the neighboring rostral periventricular nucleus (PeVN), and in the arcuate (ARC) nucleus of the mammalian hypothalamus. In the ARC, the KISS neurons that co-express neurokinin B (NKB) and dynorphin A (Dyn) are named KNDy cells. The South American plains vizcacha is a rodent with peculiar reproductive traits. Around mid-pregnancy, vizcacha shows the reactivation of its HPO axis with the pulsatile release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH), an essential event for the success of gestation. Considering the role of KISS system in GnRH modulation, the aim of this work was to study their neuroanatomical distribution in adult vizcachas. AVPV showed sexual dimorphism with a significant smaller area in males (t-Test, p < 0.05), and KISS immunoreactivity was detected in somas and varicosities homogenously distributed in the AVPV with a concordant sex-related expression pattern. NKB and Dyn expression was also observed in cytoplasm of neurons scattered in the AVPV. Three subpopulations of neurons were detected in the AVPV: neurons expressing Dyn and NKB (DyNK cells), neurons expressing KISS and NKB (KiNK cells), and single NKB expressing neurons. Strikingly, KISS and Dyn were always expressed in different cells. In addition, in the ARC nucleus, KNDy cells were detected. On the other hand, KISS and GnRH expression was detected in different subpopulations of neurons, GnRH cells showed KISS receptor (KISSR or GPR-54) expression, and KISS immunoreactive afferent contacts were detected making close appositions onto somas and dendrites of GnRH cells. These results show similarities and differences between the KISS system in the hypothalamus of the vizcacha and other mammals, and constitute crucial observations about KISS and GnRH relation. Considering the peculiarity of HPO axis regulation in this species, the present work provides a neuroanatomical framework for the further elucidation of molecular mechanisms underlying GnRH expression and secretion.
Collapse
Affiliation(s)
- Alejandro Raúl Schmidt
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Pablo Ignacio Felipe Inserra
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Santiago Andrés Cortasa
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Sofía Proietto
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Victoria Fidel
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina
| | - Julia Halperin
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Alfredo Daniel Vitullo
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Verónica Berta Dorfman
- Centro de Estudios Biomédicos Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| |
Collapse
|
13
|
Shen X, Liu Y, Li XF, Long H, Wang L, Lyu Q, Kuang Y, O’Byrne KT. Optogenetic stimulation of Kiss1 ARC terminals in the AVPV induces surge-like luteinizing hormone secretion via glutamate release in mice. Front Endocrinol (Lausanne) 2022; 13:1036235. [PMID: 36425470 PMCID: PMC9678915 DOI: 10.3389/fendo.2022.1036235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022] Open
Abstract
Kisspeptin neurons are mainly located in the arcuate (Kiss1ARC, vis-à-vis the GnRH pulse generator) and anteroventral periventricular nucleus (Kiss1AVPV, vis-à-vis the GnRH surge generator). Kiss1ARC send fibre projections that connect with Kiss1AVPV somata. However, studies focused on the role of Kiss1ARC neurons in the LH surge are limited, and the role of Kiss1ARC projections to AVPV (Kiss1ARC→AVPV) in the preovulatory LH surge is still unknown. To investigate its function, this study used optogenetics to selectively stimulate Kiss1ARC→AVPV and measured changes in circulating LH levels. Kiss1ARC in Kiss-Cre-tdTomato mice were virally infected to express channelrhodopsin-2 proteins, and optical stimulation was applied selectively via a fibre optic cannula in the AVPV. Sustained 20 Hz optical stimulation of Kiss1ARC→AVPV from 15:30 to 16:30 h on proestrus effectively induced an immediate increase in LH reaching peak surge-like levels of around 8 ng/ml within 10 min, followed by a gradual decline to baseline over about 40 min. Stimulation at 10 Hz resulted in a non-significant increase in LH levels and 5 Hz stimulation had no effect in proestrous animals. The 20 Hz stimulation induced significantly higher circulating LH levels on proestrus compared with diestrus or estrus, which suggested that the effect of terminal stimulation is modulated by the sex steroid milieu. Additionally, intra-AVPV infusion of glutamate antagonists, AP5+CNQX, completely blocked the increase on LH levels induced by Kiss1ARC→AVPV terminal photostimulation in proestrous animals. These results demonstrate for the first time that optical stimulation of Kiss1ARC→AVPV induces an LH surge-like secretion via glutamatergic mechanisms. In conclusion, Kiss1ARC may participate in LH surge generation by glutamate release from terminal projections in the AVPV.
Collapse
Affiliation(s)
- Xi Shen
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yali Liu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiao Feng Li
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Hui Long
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Li Wang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qifeng Lyu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanping Kuang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
- *Correspondence: Kevin T. O’Byrne, ; Yanping Kuang,
| | - Kevin T. O’Byrne
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
- *Correspondence: Kevin T. O’Byrne, ; Yanping Kuang,
| |
Collapse
|
14
|
Porter DT, Goodman RL, Hileman SM, Lehman MN. Evidence that synaptic plasticity of glutamatergic inputs onto KNDy neurones during the ovine follicular phase is dependent on increasing levels of oestradiol. J Neuroendocrinol 2021; 33:e12945. [PMID: 33713519 PMCID: PMC7959185 DOI: 10.1111/jne.12945] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 01/12/2021] [Accepted: 01/26/2021] [Indexed: 01/09/2023]
Abstract
Neurones in the arcuate nucleus co-expressing kisspeptin, neurokinin B (NKB) and dynorphin (KNDy) play a critical role in the control of gonadotrophin-releasing hormone (GnRH) and luteinising hormone (LH) secretion. In sheep, KNDy neurones mediate both steroid-negative- and -positive-feedback during pulsatile and preovulatory surge secretions of GnRH/LH, respectively. In addition, KNDy neurones receive glutamatergic inputs expressing vGlut2, a glutamate transporter that serves as a marker for those terminals, from both KNDy neurones and other populations of glutamatergic neurones. Previous work reported higher numbers of vGlut2-positive axonal inputs onto KNDy neurones during the LH surge than in luteal phase ewes. In the present study, we further examined the effects of the ovarian steroids progesterone (P) and oestradiol (E2 ) on glutamatergic inputs to KNDy neurones. Ovariectomised (OVX) ewes received either no further treatment (OVX) or steroid treatments that mimicked the luteal phase (low E2 + P), and early (low E2 ) or late follicular (high E2 ) phases of the oestrous cycle (n = 4 or 5 per group). Brain sections were processed for triple-label immunofluorescent detection of NKB/vGlut2/synaptophysin and analysed using confocal microscopy. We found higher numbers of vGlut2 inputs onto KNDy neurones in high E2 compared to the other three treatment groups. These results suggest that synaptic plasticity of glutamatergic inputs onto KNDy neurones during the ovine follicular phase depend on increasing levels of E2 required for the preovulatory GnRH/surge. These synaptic changes likely contribute to the positive-feedback action of oestrogen on GnRH/LH secretion and thus the generation of the preovulatory surge in the sheep.
Collapse
Affiliation(s)
- Danielle T. Porter
- Neuroscience Graduate Program, Dept. of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center
| | | | | | - Michael N. Lehman
- Brain Health Research Institute and Department of Biological Sciences, Kent State University
- Corresponding author and reprint requests to: Michael N. Lehman, Brain Health Research Institute, Kent State University, 251K Integrated Sciences Building, Kent, Ohio, 44242-0001 USA, Phone: 330-672-2732;
| |
Collapse
|
15
|
Lin XH, Lass G, Kong LS, Wang H, Li XF, Huang HF, O’Byrne KT. Optogenetic Activation of Arcuate Kisspeptin Neurons Generates a Luteinizing Hormone Surge-Like Secretion in an Estradiol-Dependent Manner. Front Endocrinol (Lausanne) 2021; 12:775233. [PMID: 34795643 PMCID: PMC8593229 DOI: 10.3389/fendo.2021.775233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/18/2021] [Indexed: 01/31/2023] Open
Abstract
Traditionally, the anteroventral periventricular (AVPV) nucleus has been the brain area associated with luteinizing hormone (LH) surge secretion in rodents. However, the role of the other population of hypothalamic kisspeptin neurons, in the arcuate nucleus (ARC), has been less well characterized with respect to surge generation. Previous experiments have demonstrated ARC kisspeptin knockdown reduced the amplitude of LH surges, indicating that they have a role in surge amplification. The present study used an optogenetic approach to selectively stimulate ARC kisspeptin neurons and examine the effect on LH surges in mice with different hormonal administrations. LH level was monitored from 13:00 to 21:00 h, at 30-minute intervals. Intact Kiss-Cre female mice showed increased LH secretion during the stimulation period in addition to displaying a spontaneous LH surge around the time of lights off. In ovariectomized Kiss-Cre mice, optogenetic stimulation was followed by a surge-like secretion of LH immediately after the stimulation period. Ovariectomized Kiss-Cre mice with a low dose of 17β-estradiol (OVX+E) replacement displayed a surge-like increase in LH release during period of optic stimulation. No LH response to the optic stimulation was observed in OVX+E mice on the day of estradiol benzoate (EB) treatment (day 1). However, after administration of progesterone (day 2), all OVX+E+EB+P mice exhibited an LH surge during optic stimulation. A spontaneous LH surge also occurred in these mice at the expected time. Taken together, these results help to affirm the fact that ARC kisspeptin may have a novel amplificatory role in LH surge production, which is dependent on the gonadal steroid milieu.
Collapse
Affiliation(s)
- Xian-Hua Lin
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Geffen Lass
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Ling-Si Kong
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Hui Wang
- Department of Obstetrics and Gynecology, Maternal and Child Health Hospital of Songjiang District, Shanghai, China
| | - Xiao-Feng Li
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - He-Feng Huang
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Kevin T. O’Byrne
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
- *Correspondence: Kevin T. O’Byrne, kevin.o’
| |
Collapse
|
16
|
Liu Y, Li X, Shen X, Ivanova D, Lass G, He W, Chen Q, Yu S, Wang Y, Long H, Wang L, Lyu Q, Kuang Y, O’Byrne KT. Dynorphin and GABAA Receptor Signaling Contribute to Progesterone's Inhibition of the LH Surge in Female Mice. Endocrinology 2020; 161:5808894. [PMID: 32181477 PMCID: PMC7153819 DOI: 10.1210/endocr/bqaa036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 02/28/2020] [Indexed: 01/02/2023]
Abstract
Progesterone can block estrogen-induced luteinising hormone (LH) surge secretion and can be used clinically to prevent premature LH surges. The blocking effect of progesterone on the LH surge is mediated through its receptor in the anteroventral periventricular nucleus (AVPV) of the hypothalamus. However, the underlying mechanisms are unclear. The preovulatory LH surge induced by estrogen is preceded by a significant reduction in hypothalamic dynorphin and gamma-aminobutyric acid (GABA) release. To test the detailed roles of dynorphin and GABA in an LH surge blockade by progesterone, ovariectomized and 17β-estradiol capsule-implanted (OVX/E2) mice received simultaneous injections of estradiol benzoate (EB) and progesterone (P) or vehicle for 2 consecutive days. The LH level was monitored from 2:30 pm to 8:30 pm at 30-minute intervals. Progesterone coadministration resulted in the LH surge blockade. A continuous microinfusion of the dynorphin receptor antagonist nor-BNI or GABAA receptor antagonist bicuculline into the AVPV from 3:00 pm to 7:00 pm reversed the progesterone-mediated blockade of the LH surge in 7 of 9 and 6 of 10 mice, respectively. In addition, these LH surges started much earlier than the surge induced by estrogen alone. However, 5 of 7 progesterone-treated mice did not show LH surge secretion after microinfusion with the GABAB receptor antagonist CGP-35348. Additionally, peripheral administration of kisspeptin-54 promotes LH surge-like release in progesterone treated mice. These results demonstrated that the progesterone-mediated suppression of the LH surge is mediated by an increase in dynorphin and GABAA receptor signaling acting though kisspeptin neurons in the AVPV of the hypothalamus in female mice.
Collapse
Affiliation(s)
- Yali Liu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Pudong New Area, Shanghai, China
| | - Xiaofeng Li
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
| | - Xi Shen
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
| | - Deyana Ivanova
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
| | - Geffen Lass
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
| | - Wen He
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Qiuju Chen
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Sha Yu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Yun Wang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Hui Long
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Li Wang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Qifeng Lyu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Yanping Kuang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
- Correspondence: Kevin O’Byrne, PhD, 2.92W Hodgkin Building, Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, SE1 1UL. E-mail: ; or Yanping Kuang, Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China. E-mail:
| | - Kevin T O’Byrne
- Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, King’s College London, Guy’s Campus, UK
- Correspondence: Kevin O’Byrne, PhD, 2.92W Hodgkin Building, Department of Women and Children’s Health, Faculty of Life Sciences and Medicine, Guy’s Campus, King’s College London, London, SE1 1UL. E-mail: ; or Yanping Kuang, Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China. E-mail:
| |
Collapse
|
17
|
Ieda N, Minabe S, Ikegami K, Watanabe Y, Sugimoto Y, Sugimoto A, Kawai N, Ishii H, Inoue N, Uenoyama Y, Tsukamura H. GnRH(1-5), a metabolite of gonadotropin-releasing hormone, enhances luteinizing hormone release via activation of kisspeptin neurons in female rats. Endocr J 2020; 67:409-418. [PMID: 31941848 DOI: 10.1507/endocrj.ej19-0444] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Accumulating evidence suggests that kisspeptin neurons in the arcuate nucleus (ARC), which coexpress neurokinin B and dynorphin, are involved in gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) pulse generation, while the anteroventral periventricular nucleus (AVPV) kisspeptin neurons are responsible for GnRH/LH surge generation. The present study aims to examine whether GnRH(1-5), a GnRH metabolite, regulates LH release via kisspeptin neurons. GnRH(1-5) was intracerebroventricularly injected to ovariectomized and estrogen-treated Wistar-Imamichi female rats. Immediately after the central GnRH(1-5) administration at 2 nmol, plasma LH concentration increased, resulting in significantly higher levels of the area under the curve and baseline of plasma LH concentrations compared to vehicle-injected controls. On the other hand, in Kiss1 knockout rats, GnRH(1-5) administration failed to affect LH secretion, suggesting that the facilitatory effect of GnRH(1-5) on LH release is mediated by kisspeptin neurons. Double in situ hybridization (ISH) for Kiss1 and Gpr101, a GnRH(1-5) receptor gene, revealed that few Kiss1-expressing cells coexpress Gpr101 in both ARC and AVPV. On the other hand, double ISH for Gpr101 and Slc17a6, a glutamatergic marker gene, revealed that 29.2% of ARC Gpr101-expressing cells coexpress Slc17a6. Further, most of the AVPV and ARC Kiss1-expressing cells coexpress Grin1, a gene encoding a subunit of NMDA receptor. Taken together, these results suggest that the GnRH(1-5)-GPR101 signaling facilitates LH release via indirect activation of kisspeptin neurons and that glutamatergic neurons may mediate the signaling. This provides a new aspect of kisspeptin- and GnRH-neuronal communication with the presence of stimulation from GnRH to kisspeptin neurons in female rats.
Collapse
Affiliation(s)
- Nahoko Ieda
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Shiori Minabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Kana Ikegami
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Youki Watanabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yusuke Sugimoto
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Arisa Sugimoto
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Narumi Kawai
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hirotaka Ishii
- Department of Anatomy and Neurobiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Naoko Inoue
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshihisa Uenoyama
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| |
Collapse
|
18
|
Herbison AE. A simple model of estrous cycle negative and positive feedback regulation of GnRH secretion. Front Neuroendocrinol 2020; 57:100837. [PMID: 32240664 DOI: 10.1016/j.yfrne.2020.100837] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 12/19/2022]
Abstract
The gonadal steroids estradiol and progesterone exert critical suppressive and stimulatory actions upon the brain to control gonadotropin-releasing hormone (GnRH) release that drives the estrous/menstrual cycle. A simple model for understanding these interactions is proposed in which the activity of the "GnRH pulse generator" is restrained by post-ovulation progesterone secretion to bring about the estrus/luteal phase slowing of pulsatile gonadotropin release, while the activity of the "GnRH surge generator" is primed by the rising follicular phase levels of estradiol to generate the pre-ovulatory surge. The physiological fluctuations in estradiol levels across the cycle are considered to clamp the GnRH pulse generator output at a constant level. Independent pulse and surge generator circuitries regulate the excitability of different compartments of the GnRH neuron. As such, GnRH secretion through the cycle is determined simply by the summed influence of the estradiol-clamped, progesterone-regulated pulse and estradiol-regulated surge generators on the GnRH neuron.
Collapse
Affiliation(s)
- Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin 9054, New Zealand.
| |
Collapse
|
19
|
Silva CC, Cortés GD, Javier CY, Flores A, Domínguez R. A neural circadian signal essential for ovulation is generated in the suprachiasmatic nucleus during each stage of the oestrous cycle. Exp Physiol 2019; 105:258-269. [PMID: 31769118 DOI: 10.1113/ep087942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/25/2019] [Indexed: 12/31/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is the suprachiasmatic nucleus the structure that generates the neural circadian signals that occur during every stage of the oestrous cycle, not only pro-oestrus, and are these signals essential for proper regulation of ovulation? What is the main finding and its importance? Transient inhibition of Na+ -dependent action potentials in the suprachiasmatic nucleus by tetrodotoxin microinjection at 14.00 h inhibits ovulation irrespective of the stage of the oestrous cycle at which the procedure is performed. Microinjection of saline solution into the suprachiasmatic nucleus has a disruptive effect on ovulation that depends on the stage of the cycle at which it is administered. ABSTRACT Reproduction is a highly timed process that depends on both the reproductive and circadian systems. The core oscillator of the latter resides at the suprachiasmatic nuclei (SCN) and it is pivotal for the regulation of the pro-oestrus pre-ovulatory surge of gonadotropins in females. There is evidence to suggest that this system may be involved in the regulation of neuroendocrine events that are essential for ovulation and that occur prior to pro-oestrus. We explored this possibility by transiently inactivating the SCN. Female rats were implanted with guide cannulas aimed at the SCN. After recovery of the oestrous cycle, animals were injected with tetrodotoxin (TTX), artificial cerebrospinal fluid (ACSF) or saline solution while freely moving. Injections were performed at 14.00 h of each stage of the oestrous cycle. Animals were killed on the next predicted oestrus day, the number of ova shed was counted and intact rats at oestrus stage were used as absolute control. ACSF did not modify ovulation. Saline solution blocked ovulation in oestrus- and dioestrus-injected rats. Irrespectively of the stage of the oestrous cycle, TTX blocked ovulation. These results lead us to suggest that a neural circadian signal, pivotal for triggering the gonadotropin pre-ovulatory surge, arises from the SCN during the critical window of pro-oestrus. We also suggest that a similar signal, needed for the regulation of other events that are indispensable for proper regulation of ovulation, is also generated in this nucleus during the other stages of the cycle at a similar time.
Collapse
Affiliation(s)
- Carlos-Camilo Silva
- Chronobiology of Reproduction Research Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México.,Developmental Biology Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México
| | - Georgina Daniela Cortés
- Chronobiology of Reproduction Research Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México
| | - Cintia Yolanda Javier
- Chronobiology of Reproduction Research Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México
| | - Angélica Flores
- Chronobiology of Reproduction Research Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México.,Developmental Biology Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México
| | - Roberto Domínguez
- Chronobiology of Reproduction Research Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México.,Developmental Biology Lab, Biology of Reproduction Research Unit, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, México
| |
Collapse
|
20
|
Gotlieb N, Baker CN, Moeller J, Kriegsfeld LJ. Time-of-day-dependent sensitivity of the reproductive axis to RFamide-related peptide-3 inhibition in female Syrian hamsters. J Neuroendocrinol 2019; 31:e12798. [PMID: 31550401 PMCID: PMC6991702 DOI: 10.1111/jne.12798] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 08/15/2019] [Accepted: 09/19/2019] [Indexed: 12/15/2022]
Abstract
In spontaneously ovulating rodent species, the timing of the luteinising hormone (LH) surge is controlled by the master circadian pacemaker in the suprachiasmatic nucleus (SCN). The SCN initiates the LH surge via the coordinated control of two opposing neuropeptidergic systems that lie upstream of the gonadotrophin-releasing hormone (GnRH) neuronal system: the stimulatory peptide, kisspeptin, and the inhibitory peptide, RFamide-related peptide-3 (RFRP-3; the mammalian orthologue of avian gonadotrophin-inhibitory hormone [GnIH]). We have previously shown that the GnRH system exhibits time-dependent sensitivity to kisspeptin stimulation, further contributing to the precise timing of the LH surge. To examine whether this time-dependent sensitivity of the GnRH system is unique to kisspeptin or a more common mechanism of regulatory control, we explored daily changes in the response of the GnRH system to RFRP-3 inhibition. Female Syrian hamsters were ovariectomised to eliminate oestradiol (E2 )-negative-feedback and RFRP-3 or saline was centrally administered in the morning or late afternoon. LH concentrations and Lhβ mRNA expression did not differ between morning RFRP-3-and saline-treated groups, although they were markedly suppressed by RFRP-3 administration in the afternoon. However, RFRP-3 inhibition of circulating LH at the time of the surge does not appear to act via the GnRH system because no differences in medial preoptic area Gnrh or RFRP-3 receptor Gpr147 mRNA expression were observed. Rather, RFRP-3 suppressed arcuate nucleus Kiss1 mRNA expression and potentially impacted pituitary gonadotrophs directly. Taken together, these findings reveal time-dependent responsiveness of the reproductive axis to RFRP-3 inhibition, possibly via variation in the sensitivity of arcuate nucleus kisspeptin neurones to this neuropeptide.
Collapse
Affiliation(s)
- Neta Gotlieb
- Department of Psychology, University of California Berkeley, Berkeley, CA, USA
| | - Cydni N. Baker
- Department of Psychology, University of California Berkeley, Berkeley, CA, USA
| | - Jacob Moeller
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - Lance J. Kriegsfeld
- Department of Psychology, University of California Berkeley, Berkeley, CA, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
- Graduate Group in Endocrinology, University of California Berkeley, Berkeley, CA, USA
- The Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| |
Collapse
|
21
|
Moore AM, Coolen LM, Lehman MN. Kisspeptin/Neurokinin B/Dynorphin (KNDy) cells as integrators of diverse internal and external cues: evidence from viral-based monosynaptic tract-tracing in mice. Sci Rep 2019; 9:14768. [PMID: 31611573 PMCID: PMC6791851 DOI: 10.1038/s41598-019-51201-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/25/2019] [Indexed: 02/01/2023] Open
Abstract
Neurons in the hypothalamic arcuate nucleus (ARC) that co-express kisspeptin, neurokinin B and dynorphin (KNDy cells) are essential for mammalian reproduction as key regulators of gonadotropin-releasing hormone (GnRH) secretion. Although multiple endogenous and exogenous signals act indirectly via KNDy neurons to regulate GnRH, the identity of upstream neurons that provide synaptic input to this subpopulation is unclear. We used rabies-mediated tract-tracing in transgenic Kiss1-Cre mice combined with whole-brain optical clearing and multiple-label immunofluorescence to create a comprehensive and quantitative brain-wide map of neurons providing monosynaptic input to KNDy cells, as well as identify the estrogen receptor content and peptidergic phenotype of afferents. Over 90% of monosynaptic input to KNDy neurons originated from hypothalamic nuclei in both male and female mice. The greatest input arose from non-KNDy ARC neurons, including proopiomelanocortin-expressing cells. Significant female-dominant sex differences in afferent input were detected from estrogen-sensitive hypothalamic nuclei critical for reproductive endocrine function and sexual behavior in mice, indicating KNDy cells may provide a unique site for the coordination of sex-specific behavior and gonadotropin release. These data provide key insight into the structural framework underlying the ability of KNDy neurons to integrate endogenous and environmental signals important for the regulation of reproductive function.
Collapse
Affiliation(s)
- Aleisha M Moore
- Brain Health Research Institute and Dept. of Biological Sciences, Kent State University, Kent, OH, USA.
| | - Lique M Coolen
- Brain Health Research Institute and Dept. of Biological Sciences, Kent State University, Kent, OH, USA
| | - Michael N Lehman
- Brain Health Research Institute and Dept. of Biological Sciences, Kent State University, Kent, OH, USA
| |
Collapse
|
22
|
Bittman EL. Circadian Function in Multiple Cell Types Is Necessary for Proper Timing of the Preovulatory LH Surge. J Biol Rhythms 2019; 34:622-633. [PMID: 31530063 DOI: 10.1177/0748730419873511] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The timing of the preovulatory surge of luteinizing hormone (LH), which occurs on the evening of proestrus in female mice, is determined by the circadian system. The identity of cells that control the phase of the LH surge is unclear: evidence supports a role of arginine vasopressin (AVP) cells of the suprachiasmatic nucleus (SCN), but it is not known whether vasopressinergic neurons are necessary or sufficient to account for circadian control of ovulation. Among other cell types, evidence also suggests important roles of circadian function of kisspeptin cells of the anteroventral periventricular nucleus (AvPV) and gonadotropin-releasing hormone (GnRH) neurons of the preoptic area (POA), whose discharge is immediately responsible for the discharge of LH from the anterior pituitary. The present studies used an ovariectomized, estradiol-treated preparation to determine critical cell types whose clock function is critical to the timing of LH secretion. As expected, the LH surge occurred at or shortly after ZT12 in control mice. In further confirmation of circadian control, the surge was advanced by 2 h in tau mutant animals. The timing of the surge was altered to varying degrees by conditional deletion of Bmal1 in AVPCre, KissCreBAC, and GnRHCreBAC mice. Excision of the mutant Cnsk1e (tau) allele in AVP neurons resulted in a reversion of the surge to the ZT12. Conditional deletion of Bmal1 in Kiss1 or GnRH neurons had no noticeable effect on locomotor rhythms, but targeting of AVP neurons produced variable effects on circadian period that did not always correspond to changes in the phase of LH secretion. The results indicate that circadian function in multiple cell types is necessary for proper timing of the LH surge.
Collapse
Affiliation(s)
- Eric L Bittman
- Department of Biology and Program in Neuroscience and Behavior, University of Massachusetts, Amherst, Massachusetts
| |
Collapse
|
23
|
McQuillan HJ, Han SY, Cheong I, Herbison AE. GnRH Pulse Generator Activity Across the Estrous Cycle of Female Mice. Endocrinology 2019; 160:1480-1491. [PMID: 31083714 DOI: 10.1210/en.2019-00193] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 04/16/2019] [Indexed: 11/19/2022]
Abstract
A subpopulation of kisspeptin neurons located in the arcuate nucleus (ARN) operate as the GnRH pulse generator. The activity of this population of neurons can be monitored in real-time for long periods using kisspeptin neuron-selective GCaMP6 fiber photometry. Using this approach, we find that ARN kisspeptin neurons exhibit brief (∼50 seconds) periods of synchronized activity that precede pulses of LH in intact female mice. The dynamics and frequency of these synchronization episodes (SEs) are stable at approximately one event every 40 minutes throughout metestrus, diestrus, and proestrus, but slow considerably on estrus to occur approximately once every 10 hours. Evaluation of ARN kisspeptin neuron activity across the light-dark transition, including the time of onset of the proestrus LH surge, revealed no changes in SE frequency. Longer 24-hour recordings across proestrus into estrus demonstrated that an abrupt decrease in SEs occurred ∼4 to 5 hours after the onset of the LH surge to reach the low frequency of SEs observed on estrus. The frequency of SEs was stable across the 24-hour period from metestrus to diestrus. Administration of progesterone to diestrus mice resulted in the abrupt slowing of SEs. These observations show that the GnRH pulse generator exhibits an unvarying pattern of activity from metestrus through to the late evening of proestrus, at which time it slows dramatically, likely in response to postovulation progesterone secretion. The GnRH pulse generator maintains a constant frequency of activity across the time of the LH surge, demonstrating that it is not involved directly in surge generation.
Collapse
Affiliation(s)
- H James McQuillan
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Su Young Han
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Isaiah Cheong
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| | - Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, University of Otago School of Biomedical Sciences, Dunedin, New Zealand
| |
Collapse
|
24
|
Glucocorticoids stimulate hypothalamic dynorphin expression accounting for stress-induced impairment of GnRH secretion during preovulatory period. Psychoneuroendocrinology 2019; 99:47-56. [PMID: 30176377 DOI: 10.1016/j.psyneuen.2018.08.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/03/2018] [Accepted: 08/27/2018] [Indexed: 11/24/2022]
Abstract
Stress-induced reproductive dysfunction is frequently associated with increased glucocorticoid (GC) levels responsible for suppressed GnRH/LH secretion and impaired ovulation. Besides the major role of the hypothalamic kisspeptin system, other key regulators may be involved in such regulatory mechanisms. Herein, we identify dynorphin as a novel transcriptional target of GC. We demonstrate that only priming with high estrogen (E2) concentrations prevailing during the late prooestrus phase enables stress-like GC concentrations to specifically stimulate Pdyn (prodynorphin) expression both in vitro (GT1-7 mouse hypothalamic cell line) and ex vivo (ovariectomized E2-supplemented mouse brains). Our results indicate that stress-induced GC levels up-regulate dynorphin expression within a specific kisspeptin neuron-containing hypothalamic region (antero-ventral periventricular nucleus), thus lowering kisspeptin secretion and preventing preovulatory GnRH/LH surge at the end of the prooestrus phase. To further characterize the molecular mechanisms of E2 and GC crosstalk, chromatin immunoprecipitation experiments and luciferase reporter gene assays driven by the proximal promoter of Pdyn show that glucocorticoid receptors bind specific response elements located within the Pdyn promoter, exclusively in presence of E2. Altogether, our work provides novel understanding on how stress affects hypothalamic-pituitary-gonadal axis and underscores the role of dynorphin in mediating GC inhibitory actions on the preovulatory GnRH/LH surge to block ovulation.
Collapse
|
25
|
Briski KP, Shakya M. Mu Opioid Receptor Regulation of Gonadotropin-Releasing Hormone-Luteinizing Hormone Axis during Short-Term Food Deprivation: Role of Alpha1-Adrenoreceptor Signaling. NEURO ENDOCRINOLOGY LETTERS 2018; 39:363-370. [PMID: 30664341 PMCID: PMC7506469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/02/2018] [Indexed: 06/09/2023]
Abstract
OBJECTIVES Brain bio-energetic stability is required for optimal gonadal steroid positive-feedback activation of the gonadotropin-releasing hormone-I (GnRH-I)-pituitary luteinizing hormone (LH) neuroendocrine axis. Caudal hindbrain metabolic-sensory noradrenergic neurons counter energy deficiency by curtailing the mid-cycle LH surge. Central mu opioid receptors (mu-R) impose inhibitory effects of diverse physiological stimuli, including stress, on LH. DESIGN/MATERIAL AND METHODS To address the premise that mu-R attenuate the LH surge due to metabolic stress of food deprivation (FD), this study examined impacts of lateral ventricular administration of the selective mu-R antagonist CTOP on FD-associated patterns of GnRH-I protein expression and LH release in estradiol-primed ovariectomized female rats. RESULTS FD caused CTOP-reversible reductions in circulating LH and in micropunch-dissected neural tissue GnRH-I and upstream neurotransmitter (kisspeptin)/biosynthetic enzyme (neuronal nitric oxide synthase) protein content. FD up-regulated mu-R protein expression in reproduction-relevant preoptic structures, e.g. anteroventral periventricular (AVPV) and medial preoptic (MPN) nuclei, responses that were abolished by the alpha1-adrenergic receptor (α1A-R) inverse agonist prazosin. CONCLUSIONS Current data implicate mu-R in FD attenuation of the E positive-feedback - induced LH surge. Results imply that FD-triggered noradrenergic input to the GnRH-I/LH axis acts in part to enhance reproductive neuroendocrine sensitivity to mu-R inhibition. Further studies are needed to characterize the neurochemical phenotype of AVPV and MPN neurons that express α1A- and/or mu-R, and to determine how these cells are organized within regulatory pathways to impose FD restraint of GnRH-1.
Collapse
Affiliation(s)
- Karen P Briski
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA
| | - Manita Shakya
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA
| |
Collapse
|
26
|
Schafer D, Kane G, Colledge WH, Piet R, Herbison AE. Sex- and sub region-dependent modulation of arcuate kisspeptin neurones by vasopressin and vasoactive intestinal peptide. J Neuroendocrinol 2018; 30:e12660. [PMID: 30422333 DOI: 10.1111/jne.12660] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/11/2018] [Accepted: 11/07/2018] [Indexed: 02/04/2023]
Abstract
A population of kisspeptin neurones located in the hypothalamic arcuate nucleus (ARN) very likely represent the gonadotrophin-releasing hormone pulse generator responsible for driving pulsatile luteinising hormone secretion in mammals. As such, it has become important to understand the neural inputs that modulate the activity of ARN kisspeptin (ARNKISS ) neurones. Using a transgenic GCaMP6 mouse model allowing the intracellular calcium levels ([Ca2+ ]i ) of individual ARNKISS neurones to be assessed simultaneously, we examined whether the circadian neuropeptides vasoactive intestinal peptide (VIP) and arginine vasopressin (AVP) modulated the activity of ARNKISS neurones directly. To validate this methodology, we initially evaluated the effects of neurokinin B (NKB) on [Ca2+ ]i in kisspeptin neurones residing within the rostral, middle and caudal ARN subregions of adult male and female mice. All experiments were undertaken in the presence of tetrodotoxin and ionotropic amino acid antagonists. NKB was found to evoke an abrupt increase in [Ca2+ ]i in 95%-100% of kisspeptin neurones throughout the ARN of both sexes. By contrast, both VIP and AVP were found to primarily activate kisspeptin neurones located in the caudal ARN of female mice. Although 58% and 59% of caudal ARN kisspeptin neurones responded to AVP and VIP, respectively, in female mice, only 0%-8% of kisspeptin neurones located in other ARN subregions responded in females and 0%-12% of cells in any subregion in males (P < 0.05). These observations demonstrate unexpected sex differences and marked heterogeneity in functional neuropeptide receptor expression amongst ARNKISS neurones organised on a rostro-caudal basis. The functional significance of this unexpected influence of VIP and AVP on ARNKISS neurones remains to be established.
Collapse
Affiliation(s)
- Danielle Schafer
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Grace Kane
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - William H Colledge
- Reproductive Physiology Group, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Richard Piet
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Allan E Herbison
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| |
Collapse
|
27
|
Moore AM, Coolen LM, Porter DT, Goodman RL, Lehman MN. KNDy Cells Revisited. Endocrinology 2018; 159:3219-3234. [PMID: 30010844 PMCID: PMC6098225 DOI: 10.1210/en.2018-00389] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/05/2018] [Indexed: 12/29/2022]
Abstract
In the past decade since kisspeptin/neurokinin B/dynorphin (KNDy) cells were first identified in the mammalian hypothalamus, a plethora of new research has emerged adding insights into the role of this neuronal population in reproductive neuroendocrine function, including the basis for GnRH pulse generation and the mechanisms underlying the steroid feedback control of GnRH secretion. In this mini-review, we provide an update of evidence regarding the roles of KNDy peptides and their postsynaptic receptors in producing episodic GnRH release and assess the relative contribution of KNDy neurons to the "GnRH pulse generator." In addition, we examine recent work investigating the role of KNDy neurons as mediators of steroid hormone negative feedback and review evidence for their involvement in the preovulatory GnRH/LH surge, taking into account species differences that exist among rodents, ruminants, and primates. Finally, we summarize emerging roles of KNDy neurons in other aspects of reproductive function and in nonreproductive functions and discuss critical unresolved questions in our understanding of KNDy neurobiology.
Collapse
Affiliation(s)
- Aleisha M Moore
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - Lique M Coolen
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
- Department of Physics and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Danielle T Porter
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert L Goodman
- Department of Physiology, Pharmacology, and Neuroscience, West Virginia University, Morgantown, West Virginia
| | - Michael N Lehman
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi
| |
Collapse
|
28
|
Shakya M, Shrestha PK, Briski KP. Hindbrain 5'-Adenosine Monophosphate-activated Protein Kinase Mediates Short-term Food Deprivation Inhibition of the Gonadotropin-releasing Hormone-Luteinizing Hormone Axis: Role of Nitric Oxide. Neuroscience 2018; 383:46-59. [PMID: 29746990 DOI: 10.1016/j.neuroscience.2018.04.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 04/24/2018] [Accepted: 04/27/2018] [Indexed: 10/17/2022]
Abstract
Hindbrain-derived stimuli restrain the gonadotropin-releasing hormone (GnRH)-pituitary luteinizing hormone (LH) reproductive neuroendocrine axis during energy insufficiency. Interruption of food intake, planned or unplanned, is emblematic of modern life. This study investigated the premise that the hindbrain energy sensor 5'-adenosine monophosphate-activated protein kinase (AMPK) inhibits reproductive neuroendocrine function in short term, e.g. 18-h food-deprived (FD) estradiol (E)-implanted ovariectomized female rats. Intra-caudal fourth ventricular administration of the AMPK inhibitor Compound C (Cc) reversed FD-induced inhibition of rostral preoptic (rPO) GnRH protein expression and LH release in animals given E to replicate proestrus (high-E dose-, but not metestrus (low-E dose)-stage plasma steroid levels. FD caused Cc-reversible augmentation or diminution of preoptic norepinephrine (NE) activity in high- versus low-E rats, respectively, and AMPK-independent reductions in hypothalamic NE accumulation in the latter. Nitric oxide (NO) and kisspeptin are key stimulatory signals for the preovulatory LH surge. Here, FD inhibited rPO neuronal nitric oxide synthase protein expression in high-, but not low-E-dosed animals. Lateral ventricular delivery of the NO donor 3-morpholinosydnonimine (SIN-1) reversed inhibitory GnRH and LH responses to FD in high-E rats, and normalized rPO Vglut2, anteroventral periventricular KiSS1, and dorsomedial hypothalamic RFRP-3 mRNA and/or protein profiles. Data show that FD curtails reproductive neuroendocrine outflow by hindbrain AMPK-dependent mechanisms in the presence of peak estrous cycle E levels. Results indicate that neural networks linking this sensor to GnRH neurons likely involve NO signaling, which may function upstream of one or more neurotransmitters identified here by SIN-1-reversible inhibitory responses to FD.
Collapse
Affiliation(s)
- Manita Shakya
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, College of Health and Pharmaceutical Sciences, The University of Louisiana at Monroe, Monroe, LA 71201, United States
| | - Prem K Shrestha
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, College of Health and Pharmaceutical Sciences, The University of Louisiana at Monroe, Monroe, LA 71201, United States
| | - Karen P Briski
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, College of Health and Pharmaceutical Sciences, The University of Louisiana at Monroe, Monroe, LA 71201, United States.
| |
Collapse
|
29
|
Weems PW, Lehman MN, Coolen LM, Goodman RL. The Roles of Neurokinins and Endogenous Opioid Peptides in Control of Pulsatile LH Secretion. VITAMINS AND HORMONES 2018; 107:89-135. [PMID: 29544644 DOI: 10.1016/bs.vh.2018.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Work over the last 15 years on the control of pulsatile LH secretion has focused largely on a set of neurons in the arcuate nucleus (ARC) that contains two stimulatory neuropeptides, critical for fertility in humans (kisspeptin and neurokinin B (NKB)) and the inhibitory endogenous opioid peptide (EOP), dynorphin, and are now known as KNDy (kisspeptin-NKB-dynorphin) neurons. In this review, we consider the role of each of the KNDy peptides in the generation of GnRH pulses and the negative feedback actions of ovarian steroids, with an emphasis on NKB and dynorphin. With regard to negative feedback, there appear to be important species differences. In sheep, progesterone inhibits GnRH pulse frequency by stimulating dynorphin release, and estradiol inhibits pulse amplitude by suppressing kisspeptin. In rodents, the role of KNDy neurons in estrogen negative feedback remains controversial, progesterone may inhibit GnRH via dynorphin, but the physiological significance of this action is unclear. In primates, an EOP, probably dynorphin, mediates progesterone negative feedback, and estrogen inhibits kisspeptin expression. In contrast, there is now compelling evidence from several species that kisspeptin is the output signal from KNDy neurons that drives GnRH release during a pulse and may also act within the KNDy network to affect pulse frequency. NKB is thought to act within this network to initiate each pulse, although there is some redundancy in tachykinin signaling in rodents. In ruminants, dynorphin terminates GnRH secretion at the end of pulse, most likely acting on both KNDy and GnRH neurons, but the data on the role of this EOP in rodents are conflicting.
Collapse
Affiliation(s)
- Peyton W Weems
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | - Michael N Lehman
- University of Mississippi Medical Center, Jackson, MS, United States
| | - Lique M Coolen
- University of Mississippi Medical Center, Jackson, MS, United States
| | | |
Collapse
|
30
|
Liu Y, Li S, Wang Q, Chen Y, Qi X, Liu Y, Liu X, Lin H, Zhang Y. Molecular identification of the Dyn/Kor system and its potential role in the reproductive axis of goldfish. Gen Comp Endocrinol 2018; 257:29-37. [PMID: 28242307 DOI: 10.1016/j.ygcen.2017.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 12/12/2022]
Abstract
To ascertain the significance of the dynorphin/kappa-opioid receptor (Dyn/Kor) system in fish reproduction, prodynorphin (pdyn) cDNA was cloned from goldfish. Two Dyn peptides (DynA and DynB) are present in the goldfish prodynorphin precursor. Both DynA and DynB are biologically active as they are able to functionally interact with the goldfish Kor expressed in cultured eukaryotic cells to suppress forskolin-induced CRE promoter activity. RT-PCR analysis showed that pdyn is widely expressed in brain regions, with the highest expression in hypothalamus. During ovarian development, hypothalamic pdyn and kor mRNA levels are lower in the early vitellogenic stage. Then the biological effects of Dyn peptides on salmon gonadotropin releasing hormone (sgnrh), luteinizing hormone beta (lhb) and follicle stimulating hormone beta (fshb) mRNA synthesis were further investigated in goldfish. Intraperitoneal injections of DynA and DynB significantly reduced hypothalamic sgnrh and pituitary lhb and fshb mRNA levels in male goldfish, but these two peptides only down-regulated sgnrh and lhb mRNA expression in female goldfish. In vitro studies revealed that DynA also decreased lhb mRNA levels in primary cultures of pituitary cells, indicating that this peptide can exert its actions at the pituitary level. Our findings suggest that the Dyn/Kor system plays a negative role in regulating the reproductive axis in goldfish.
Collapse
Affiliation(s)
- Yali Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Shuisheng Li
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| | - Qing Wang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yu Chen
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xin Qi
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yun Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xiaochun Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Haoran Lin
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yong Zhang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| |
Collapse
|
31
|
das Neves W, de Oliveira LF, da Silva RP, Alves CRR, Lancha AH. Fasting: a major limitation for resistance exercise training effects in rodents. ACTA ACUST UNITED AC 2017; 51:e5427. [PMID: 29185588 PMCID: PMC5685054 DOI: 10.1590/1414-431x20175427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/28/2017] [Indexed: 11/21/2022]
Abstract
Protocols that mimic resistance exercise training (RET) in rodents present several limitations, one of them being the electrical stimulus, which is beyond the physiological context observed in humans. Recently, our group developed a conditioning system device that does not use electric shock to stimulate rats, but includes fasting periods before each RET session. The current study was designed to test whether cumulative fasting periods have some influence on skeletal muscle mass and function. Three sets of male Wistar rats were used in the current study. The first set of rats was submitted to a RET protocol without food restriction. However, rats were not able to perform exercise properly. The second and third sets were then randomly assigned into three experimental groups: 1) untrained control rats, 2) untrained rats submitted to fasting periods, and 3) rats submitted to RET including fasting periods before each RET session. While the second set of rats performed a short RET protocol (i.e., an adaptation protocol for 3 weeks), the third set of rats performed a longer RET protocol including overload (i.e., 8 weeks). After the short-term protocol, cumulative fasting periods promoted loss of weight (P<0.001). After the longer RET protocol, no difference was observed for body mass, extensor digitorum longus (EDL) morphology or skeletal muscle function (P>0.05 for all). Despite no effects on EDL mass, soleus muscle displayed significant atrophy in the fasting experimental groups (P<0.01). Altogether, these data indicate that fasting is a major limitation for RET in rats.
Collapse
Affiliation(s)
- W das Neves
- Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - L F de Oliveira
- Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - R P da Silva
- Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - C R R Alves
- Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - A H Lancha
- Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| |
Collapse
|
32
|
He W, Li X, Adekunbi D, Liu Y, Long H, Wang L, Lyu Q, Kuang Y, O'Byrne KT. Hypothalamic effects of progesterone on regulation of the pulsatile and surge release of luteinising hormone in female rats. Sci Rep 2017; 7:8096. [PMID: 28808344 PMCID: PMC5556103 DOI: 10.1038/s41598-017-08805-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/12/2017] [Indexed: 01/10/2023] Open
Abstract
Progesterone can block the oestradiol-induced GnRH/LH surge and inhibit LH pulse frequency. Recent studies reported that progesterone prevented premature LH surges during ovarian hyperstimulation in women. As the most potent stimulator of GnRH/LH release, kisspeptin is believed to mediate the positive and negative feedback effects of oestradiol in the hypothalamic anteroventral periventricular (AVPV) and arcuate (ARC) nuclei, while the region-specific role of progesterone receptors in these nuclei remains unknown. This study examined the hypothesis that progesterone inhibits LH surge and pulsatile secretion via its receptor in the ARC and/or AVPV nuclei. Adult female rats received a single injection of pregnant mare serum gonadotropin followed by progesterone or vehicle. Progesterone administration resulted in a significant prolongation of the oestrous cycle and blockade of LH surge. However, microinjection of the progesterone receptor antagonist, RU486, into the AVPV reversed the prolonged cycle length and rescued the progesterone blockade LH surge, while RU486 into the ARC shortened LH pulse interval in the progesterone treated rats. These results demonstrated that progesterone's inhibitory effect on the GnRH/LH surge and pulsatile secretion is mediated by its receptor in the kisspeptin enriched hypothalamic AVPV and ARC respectively, which are essential for progesterone regulation of oestrous cyclicity in rats.
Collapse
Affiliation(s)
- Wen He
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Xiaofeng Li
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, Guy's Campus, London, UK
| | - Daniel Adekunbi
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, Guy's Campus, London, UK
| | - Yali Liu
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Hui Long
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Li Wang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Qifeng Lyu
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Yanping Kuang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
| | - Kevin T O'Byrne
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, Guy's Campus, London, UK.
| |
Collapse
|
33
|
Fergani C, Routly JE, Jones DN, Pickavance LC, Smith RF, Dobson H. KNDy neurone activation prior to the LH surge of the ewe is disrupted by LPS. Reproduction 2017. [PMID: 28630099 DOI: 10.1530/rep-17-0191] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In the ewe, steroid hormones act on the hypothalamic arcuate nucleus (ARC) to initiate the GnRH/LH surge. Within the ARC, steroid signal transduction may be mediated by estrogen receptive dopamine-, β-endorphin- or neuropeptide Y (NPY)-expressing cells, as well as those co-localising kisspeptin, neurokinin B (NKB) and dynorphin (termed KNDy). We investigated the time during the follicular phase when these cells become activated (i.e., co-localise c-Fos) relative to the timing of the LH surge onset and may therefore be involved in the surge generating mechanism. Furthermore, we aimed to elucidate whether these activation patterns are altered after lipopolysaccharide (LPS) administration, which is known to inhibit the LH surge. Follicular phases of ewes were synchronised by progesterone withdrawal and blood samples were collected every 2 h. Hypothalamic tissue was retrieved at various times during the follicular phase with or without the administration of LPS (100 ng/kg). The percentage of activated dopamine cells decreased before the onset of sexual behaviour, whereas activation of β-endorphin decreased and NPY activation tended to increase during the LH surge. These patterns were not disturbed by LPS administration. Maximal co-expression of c-Fos in dynorphin immunoreactive neurons was observed earlier during the follicular phase, compared to kisspeptin and NKB, which were maximally activated during the surge. This indicates a distinct role for ARC dynorphin in the LH surge generation mechanism. Acute LPS decreased the percentage of activated dynorphin and kisspeptin immunoreactive cells. Thus, in the ovary-intact ewe, KNDy neurones are activated prior to the LH surge onset and this pattern is inhibited by the administration of LPS.
Collapse
Affiliation(s)
- C Fergani
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| | - J E Routly
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| | - D N Jones
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| | - L C Pickavance
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| | - R F Smith
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| | - H Dobson
- School of Veterinary Science, University of Liverpool, Liverpool, UK
| |
Collapse
|
34
|
Abstract
This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
| |
Collapse
|
35
|
Abstract
PURPOSE OF REVIEW The mechanism of puberty initiation remains an enigma, despite extensive research in the field. Pulsatile pituitary gonadotropin secretion under the guidance of hypothalamic gonadotropin-releasing hormone (GnRH) constitutes a sine qua non for pubertal onset. In turn, the secretion of GnRH in the human hypothalamus is regulated by kisspeptin and its receptor as well as by permissive or opposing signals mediated by neurokinin B and dynorphin acting on their respective receptors. These three supra-GnRH regulators compose the Kisspeptin, Neurokinin B and Dynorhin neurons (KNDy) system, a key player in pubertal onset and progression. RECENT FINDINGS The recent discovery that makorin ring finger protein 3 is also involved in puberty initiation provided further insights into the regulation of the KNDy pathway. In fact, the inhibitory (γ-amino butyric acid, neuropeptide Y, and RFamide-related peptide-3) and stimulatory signals (glutamate) acting upstream of KNDy called into question the role of makorin ring finger protein 3 as the gatekeeper of puberty. Meanwhile, the findings that 'neuroestradiol' produced locally and endocrine disruptors from the environment may influence GnRH secretion is intriguing. Finally, epigenetic mechanisms have been implicated in pubertal onset through recently discovered mechanisms. SUMMARY The exact molecular machinery underlying puberty initiation in humans is under intensive investigation. In this review, we summarize research evidence in the field, while emphasizing the areas of uncertainty and underlining the impact of current information on the evolving theory regarding this fascinating phenomenon.
Collapse
|
36
|
Stathopoulos AM, Helena CV, Cristancho-Gordo R, Gonzalez-Iglesias AE, Bertram R. Influence of dynorphin on estradiol- and cervical stimulation-induced prolactin surges in ovariectomized rats. Endocrine 2016; 53:585-94. [PMID: 27038317 DOI: 10.1007/s12020-016-0938-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/21/2016] [Indexed: 11/28/2022]
Abstract
Prolactin is an anterior pituitary hormone necessary for fertility, pregnancy maintenance, lactation, and aspects of maternal behavior. In rodents, there is a surge of prolactin on the afternoon of proestrus, and a semi-circadian pattern of prolactin surges during early pregnancy, with a diurnal and nocturnal surge every day. Both of these patterns can be replicated in ovariectomized rats. A prior study demonstrated that central antagonism of κ-opioid receptors, the target of dynorphin, largely abolished the nocturnal prolactin surge in pregnant rats. We build on this to determine whether dynorphin, perhaps from the arcuate population that co-express kisspeptin, neurokinin B, and dynorphin (KNDy neurons), also contributes to the estradiol- or cervical stimulation-induced surges in ovariectomized rats. Ovariectomized rats were treated with either estradiol or cervical stimulation to induce prolactin surge(s). Blood samples were taken around the expected surge time to determine the effect of either acute κ-opioid receptor antagonism or previous chemical ablation of the KNDy population on prolactin levels. Dynorphin antagonism does significantly disrupt the nocturnal prolactin surge, but it does not contribute to the estradiol-induced surge. Chemical ablation of KNDy neurons had opposite effects; ablation of 40 % of the KNDy neurons had no impact on the nocturnal prolactin surge, while a somewhat larger ablation significantly reduced the size of the estradiol-induced surge. We conclude that dynorphin is likely a controlling factor for the nocturnal surge induced by cervical stimulation, and that other KNDy neuron products must play a role in the estradiol-induced surge.
Collapse
Affiliation(s)
- Andrea M Stathopoulos
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Cleyde V Helena
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Ruth Cristancho-Gordo
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Arturo E Gonzalez-Iglesias
- Program in Neuroscience and Departments of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Richard Bertram
- Program in Neuroscience and Departments of Mathematics, Florida State University, Tallahassee, FL, 32306, USA.
| |
Collapse
|
37
|
Briski KP, Shrestha PK. Hindbrain estrogen receptor-beta antagonism normalizes reproductive and counter-regulatory hormone secretion in hypoglycemic steroid-primed ovariectomized female rats. Neuroscience 2016; 331:62-71. [PMID: 27316550 DOI: 10.1016/j.neuroscience.2016.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/08/2016] [Accepted: 06/09/2016] [Indexed: 12/15/2022]
Abstract
Hindbrain dorsal vagal complex A2 noradrenergic signaling represses the pre-ovulatory luteinizing hormone (LH) surge in response to energy deficiency. Insulin-induced hypoglycemia augments A2 neuron adenosine 5'-monophosphate-activated protein kinase (AMPK) activity and estrogen receptor-beta (ERβ) expression, coincident with LH surge suppression. We hypothesized that ERβ is critical for hypoglycemia-associated patterns of LH secretion and norepinephrine (NE) activity in key reproduction-relevant forebrain structures. The neural mechanisms responsible for tight coupling of systemic energy balance and procreation remain unclear; here, we investigated whether ERβ-dependent hindbrain signals also control glucose counter-regulatory responses to hypoglycemia. Gonadal steroid-primed ovariectomized female rats were pretreated by caudal fourth ventricular administration of the ERβ antagonist 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl]phenol (PHTPP) or vehicle before insulin injection at LH surge onset. Western blot analysis of laser-microdissected A2 neurons revealed hypoglycemic intensification of AMPK activity and dopamine-β-hydroxylase protein expression; the latter response was attenuated by PHTPP pretreatment. PHTPP regularized LH release, but not preoptic GnRH-I precursor protein expression in insulin-injected rats, and reversed hypoglycemic stimulation of glucagon and corticosterone secretion. Hypoglycemia caused PHTPP-reversible changes in NE and prepro-kisspeptin protein content in the hypothalamic arcuate (ARH), but not anteroventral periventricular nucleus. Results provide novel evidence for ERβ-dependent caudal hindbrain regulation of LH and counter-regulatory hormone secretion during hypoglycemia. Observed inhibition of LH likely involves mechanisms at the axon terminal that impede GnRH neurotransmission. Data also show that caudal hindbrain ERβ exerts site-specific control of NE activity in forebrain projection sites during hypoglycemia, including the ARH where prepro-kisspeptin may be a target of that signaling.
Collapse
Affiliation(s)
- Karen P Briski
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71291, United States.
| | - Prem K Shrestha
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71291, United States
| |
Collapse
|
38
|
Mittelman-Smith MA, Krajewski-Hall SJ, McMullen NT, Rance NE. Ablation of KNDy Neurons Results in Hypogonadotropic Hypogonadism and Amplifies the Steroid-Induced LH Surge in Female Rats. Endocrinology 2016; 157:2015-27. [PMID: 26937713 PMCID: PMC4870865 DOI: 10.1210/en.2015-1740] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the human infundibular (arcuate) nucleus, a subpopulation of neurons coexpress kisspeptin and neurokinin B (NKB), 2 peptides required for normal reproductive function. A homologous group of neurons exists in the arcuate nucleus of rodents, termed KNDy neurons based on the coexpression of kisspeptin, NKB, and dynorphin. To study their function, we recently developed a method to selectively ablate KNDy neurons using NK3-SAP, a neurokinin 3 receptor agonist conjugated to saporin (SAP). Here, we ablated KNDy neurons in female rats to determine whether these neurons are required for estrous cyclicity and the steroid induced LH surge. NK3-SAP or Blank-SAP (control) was microinjected into the arcuate nucleus using stereotaxic surgery. After monitoring vaginal smears for 3-4 weeks, rats were ovariectomized and given 17β-estradiol and progesterone in a regimen that induced an afternoon LH surge. Rats were killed at the time of peak LH levels, and brains were harvested for NKB and dual labeled GnRH/Fos immunohistochemistry. In ovary-intact rats, ablation of KNDy neurons resulted in hypogonadotropic hypogonadism, characterized by low levels of serum LH, constant diestrus, ovarian atrophy with increased follicular atresia, and uterine atrophy. Surprisingly, the 17β-estradiol and progesterone-induced LH surge was 3 times higher in KNDy-ablated rats. Despite the marked increase in the magnitude of the LH surge, the number of GnRH or anterior ventral periventricular nucleus neurons expressing Fos was not significantly different between groups. Our studies show that KNDy neurons are essential for tonic levels of serum LH and estrous cyclicity and may play a role in limiting the magnitude of the LH surge.
Collapse
Affiliation(s)
- Melinda A Mittelman-Smith
- Departments of Pathology (M.A.M.-S., S.J.K.-H., N.E.R.) and Cellular and Molecular Medicine and Neurology (N.T.M., N.E.R.) and The Evelyn F. McKnight Brain Institute (N.E.R.), University of Arizona College of Medicine, Tucson, Arizona 85724
| | - Sally J Krajewski-Hall
- Departments of Pathology (M.A.M.-S., S.J.K.-H., N.E.R.) and Cellular and Molecular Medicine and Neurology (N.T.M., N.E.R.) and The Evelyn F. McKnight Brain Institute (N.E.R.), University of Arizona College of Medicine, Tucson, Arizona 85724
| | - Nathaniel T McMullen
- Departments of Pathology (M.A.M.-S., S.J.K.-H., N.E.R.) and Cellular and Molecular Medicine and Neurology (N.T.M., N.E.R.) and The Evelyn F. McKnight Brain Institute (N.E.R.), University of Arizona College of Medicine, Tucson, Arizona 85724
| | - Naomi E Rance
- Departments of Pathology (M.A.M.-S., S.J.K.-H., N.E.R.) and Cellular and Molecular Medicine and Neurology (N.T.M., N.E.R.) and The Evelyn F. McKnight Brain Institute (N.E.R.), University of Arizona College of Medicine, Tucson, Arizona 85724
| |
Collapse
|