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Payant MA, Spencer CD, Ly NKK, Chee MJ. Inhibitory actions of melanin-concentrating hormone in the lateral septum. J Physiol 2024. [PMID: 38874572 DOI: 10.1113/jp284845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/21/2024] [Indexed: 06/15/2024] Open
Abstract
Melanin-concentrating hormone (MCH) neurons can co-express several neuropeptides or neurotransmitters and send widespread projections throughout the brain. Notably, there is a dense cluster of nerve terminals from MCH neurons in the lateral septum (LS) that innervate LS cells by glutamate release. The LS is also a key region integrating stress- and anxiety-like behaviours, which are also emerging roles of MCH neurons. However, it is not known if or where the MCH peptide acts within the LS. We analysed the projections from MCH neurons in male and female mice anteroposteriorly throughout the LS and found spatial overlap between the distribution pattern of MCH-immunoreactive (MCH-ir) fibres with MCH receptor Mchr1 mRNA hybridization or MCHR1-ir cells. This overlap was most prominent along the ventral and lateral border of the rostral part of the LS (LSr). Most MCHR1-labelled LS neurons lay adjacent to passing MCH-ir fibres, but some MCH-ir varicosities directly contacted the soma or cilium of MCHR1-labelled LS neurons. We thus performed whole-cell patch-clamp recordings from MCHR1-rich LSr regions to determine if and how LS cells respond to MCH. Bath application of MCH to acute brain slices activated a bicuculline-sensitive chloride current that directly hyperpolarized LS cells. This MCH-mediated hyperpolarization was blocked by calphostin C, which suggested that the inhibitory actions of MCH were mediated by protein kinase C-dependent activation of GABAA receptors. Taken together, these findings define potential hotspots within the LS that may elucidate the contributions of MCH to stress- or anxiety-related feeding behaviours. KEY POINTS: Melanin-concentrating hormone (MCH) neurons have dense nerve terminals within the lateral septum (LS), a key region underlying stress- and anxiety-like behaviours that are emerging roles of the MCH system, but the function of MCH in the LS is not known. We found spatial overlap between MCH-immunoreactive fibres, Mchr1 mRNA, and MCHR1 protein expression along the lateral border of the LS. Within MCHR1-rich regions, MCH directly inhibited LS cells by increasing chloride conductance via GABAA receptor activation in a protein kinase C-dependent manner. Electrophysiological MCH effects in brain slices have been elusive, and few studies have described the mechanisms of MCH action. Our findings demonstrated, to our knowledge, the first description of MCHR1 Gq-coupling in brain slices, which was previously predicted in cell or primary culture models only. Together, these findings defined hotspots and mechanistic underpinnings for MCH effects such as in feeding and anxiety-related behaviours.
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Affiliation(s)
- Mikayla A Payant
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - C Duncan Spencer
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Nikita K Koziel Ly
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Melissa J Chee
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
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2
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Kuebler IRK, Suárez M, Wakabayashi KT. Sex differences and sex-specific regulation of motivated behavior by Melanin-concentrating hormone: a short review. Biol Sex Differ 2024; 15:33. [PMID: 38570844 PMCID: PMC10993549 DOI: 10.1186/s13293-024-00608-0] [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: 11/11/2023] [Accepted: 03/23/2024] [Indexed: 04/05/2024] Open
Abstract
Recent preclinical research exploring how neuropeptide transmitter systems regulate motivated behavior reveal the increasing importance of sex as a critical biological variable. Neuropeptide systems and their central circuits both contribute to sex differences in a range of motivated behaviors and regulate sex-specific behaviors. In this short review, we explore the current research of how sex as a biological variable influences several distinct motivated behaviors that are modulated by the melanin-concentrating hormone (MCH) neuropeptide system. First, we review how MCH regulates feeding behavior within the context of energy homeostasis differently between male and female rodents. Then, we focus on MCH's role in lactation as a sex-specific process within the context of energy homeostasis. Next, we discuss the sex-specific effects of MCH on maternal behavior. Finally, we summarize the role of MCH in drug-motivated behaviors. While these topics are traditionally investigated from different scientific perspectives, in this short review we discuss how these behaviors share commonalities within the larger context of motivated behaviors, and that sex differences discovered in one area of research may impact our understanding in another. Overall, our review highlights the need for further research into how sex differences in energy regulation associated with reproduction and parental care contribute to regulating motivated behaviors.
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Affiliation(s)
- Isabel R K Kuebler
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, 68588-0308, USA
| | - Mauricio Suárez
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, 68588-0308, USA
| | - Ken T Wakabayashi
- Neurocircuitry of Motivated Behavior Laboratory, Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, 68588-0308, USA.
- Rural Drug Addiction Research Center, University of Nebraska-Lincoln, 660 N 12th St., Lincoln, NE, 68588, USA.
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3
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The increase in the number of amylin neurons in the medial preoptic area throughout the lactational period and its relationship with melanin-concentrating hormone. J Chem Neuroanat 2023; 129:102241. [PMID: 36738851 DOI: 10.1016/j.jchemneu.2023.102241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
The amylin and the melanin-concentrating hormone [MCH] are two peptides related to energetic homeostasis. During lactation, it is possible to locate neurons expressing these peptides in the preoptic area of rat dams. In addition, it was demonstrated that the number of MCH neurons in this region is modulated by litter size. Taken together, the aims of this work were (1) to verify the time course of amylin immunoreactivity during lactation; (2) to verify whether litter size modulates the number of amylin-ir neurons (3) to verify whether there is colocalization between the amylin-ir and MCH-ir neurons. Our results show that (1) there is an increase in the number of amylin-ir neurons during lactation, which reaches a peak at postpartum day 19 and drastically reduces after weaning; (2) there is no correlation between litter size and the number of amylin-ir neurons; and (3) there is minimal overlap between amylin-ir and MCH-ir neurons.
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Orikasa C. Social Network Plasticity of Mice Parental Behavior. Front Neurosci 2022; 16:882850. [PMID: 35747212 PMCID: PMC9209706 DOI: 10.3389/fnins.2022.882850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Neural plasticity occurs during developmental stages and is essential for sexual differentiation of the brain and the ensuing sex-dependent behavioral changes in adults. Maternal behavior is primarily affected by sex-related differences in the brain; however, chronic social isolation even in mature male mice can induce maternal retrieving and crouching behavior when they are first exposed to pups. Social milieus influence the inherent behavior of adults and alter the molecular architecture in the brain, thereby allowing higher levels of associated gene expression and molecular activity. This review explores the possibility that although the development of neural circuits is closely associated with maternal behavior, the brain can still retain its neuroplasticity in adults from a neuromolecular perspective. In addition, neuronal machinery such as neurotransmitters and neuropeptides might influence sociobehavioral changes. This review also discusses that the neural circuits regulating behaviors such as parenting and infanticide (including neglect behavior), might be controlled by neural relay on melanin concentrating hormone (MCH)–oxytocin in the hypothalamus during the positive and negative mode of action in maternal behavior. Furthermore, MCH–oxytocin neural relay might contribute to the anxiolytic effect on maternal behavior, which is involved with reward circuits.
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Moinho TM, Tavares MR, Campos AM, Frazão R, Metzger M, Donato J. Simple method to induce denaturation of fluorescent proteins in free-floating brain slices. J Neurosci Methods 2022; 371:109500. [DOI: 10.1016/j.jneumeth.2022.109500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 10/19/2022]
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Oxytocin and Food Intake Control: Neural, Behavioral, and Signaling Mechanisms. Int J Mol Sci 2021; 22:ijms221910859. [PMID: 34639199 PMCID: PMC8509519 DOI: 10.3390/ijms221910859] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 09/29/2021] [Accepted: 10/03/2021] [Indexed: 11/16/2022] Open
Abstract
The neuropeptide oxytocin is produced in the paraventricular hypothalamic nucleus and the supraoptic nucleus of the hypothalamus. In addition to its extensively studied influence on social behavior and reproductive function, central oxytocin signaling potently reduces food intake in both humans and animal models and has potential therapeutic use for obesity treatment. In this review, we highlight rodent model research that illuminates various neural, behavioral, and signaling mechanisms through which oxytocin’s anorexigenic effects occur. The research supports a framework through which oxytocin reduces food intake via amplification of within-meal physiological satiation signals rather than by altering between-meal interoceptive hunger and satiety states. We also emphasize the distributed neural sites of action for oxytocin’s effects on food intake and review evidence supporting the notion that central oxytocin is communicated throughout the brain, at least in part, through humoral-like volume transmission. Finally, we highlight mechanisms through which oxytocin interacts with various energy balance-associated neuropeptide and endocrine systems (e.g., agouti-related peptide, melanin-concentrating hormone, leptin), as well as the behavioral mechanisms through which oxytocin inhibits food intake, including effects on nutrient-specific ingestion, meal size control, food reward-motivated responses, and competing motivations.
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Neural Contributions of the Hypothalamus to Parental Behaviour. Int J Mol Sci 2021; 22:ijms22136998. [PMID: 34209728 PMCID: PMC8268030 DOI: 10.3390/ijms22136998] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/23/2022] Open
Abstract
Parental behaviour is a comprehensive set of neural responses to social cues. The neural circuits that govern parental behaviour reside in several putative nuclei in the brain. Melanin concentrating hormone (MCH), a neuromodulator that integrates physiological functions, has been confirmed to be involved in parental behaviour, particularly in crouching behaviour during nursing. Abolishing MCH neurons in innate MCH knockout males promotes infanticide in virgin male mice. To understand the mechanism and function of neural networks underlying parental care and aggression against pups, it is essential to understand the basic organisation and function of the involved nuclei. This review presents newly discovered aspects of neural circuits within the hypothalamus that regulate parental behaviours.
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Campos AMP, Wasinski F, Klein MO, Bittencourt JC, Metzger M, Donato J. Fasting reduces the number of TRH immunoreactive neurons in the hypothalamic paraventricular nucleus of male rats, but not in mice. Neurosci Lett 2021; 752:135832. [PMID: 33746008 DOI: 10.1016/j.neulet.2021.135832] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 01/09/2023]
Abstract
During fasting or weight loss, the fall in leptin levels leads to suppression of thyrotropin-releasing hormone (TRH) expression in the paraventricular nucleus of the hypothalamus (PVH) and, consequently, inhibition of the hypothalamic-pituitary-thyroid (HPT) axis. However, differently than rats, just few PVHTRH neurons express the leptin receptor in mice. In the present study, male adult rats and mice were submitted to 48 -h fasting to evaluate the consequences on proTRH peptide expression at the PVH level. Additionally, the proTRH peptide expression was also assessed in the brains of leptin-deficient (Lepob/ob) mice. We observed that approximately 50 % of PVHTRH neurons of leptin-injected rats exhibited phosphorylation of the signal transducer and activator of transcription 3 (pSTAT3), a marker of leptin receptor activation. In contrast, very few PVHTRH neurons of leptin-injected mice exhibited pSTAT3. Rats submitted to 48 -h fasting showed a significant reduction in the number of PVHTRH immunoreactive neurons, as compared to fed rats. On the other hand, no changes in the number of PVHTRH immunoreactive neurons were observed between fasted and fed mice. Next, the number of TRH immunoreactive cells was determined in the PVH, dorsomedial nucleus of the hypothalamus and nucleus raphe pallidus of Lepob/ob and wild-type mice and no significant differences were observed, despite reduced plasma T4 levels in Lepob/ob mice. Taken together, these findings provide additional evidence of the important species-specific differences in the mechanisms used by fasting and/or leptin to regulate the HPT axis.
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Affiliation(s)
- Ana M P Campos
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, Brazil
| | - Frederick Wasinski
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, Brazil
| | - Marianne O Klein
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, Sao Paulo, Brazil
| | - Jackson C Bittencourt
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Anatomia, Sao Paulo, Brazil
| | - Martin Metzger
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, Brazil
| | - Jose Donato
- Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Departamento de Fisiologia e Biofisica, Sao Paulo, Brazil.
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Chaves FM, Mansano NS, Frazão R, Donato J. Tumor Necrosis Factor α and Interleukin-1β Acutely Inhibit AgRP Neurons in the Arcuate Nucleus of the Hypothalamus. Int J Mol Sci 2020; 21:ijms21238928. [PMID: 33255553 PMCID: PMC7728092 DOI: 10.3390/ijms21238928] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/31/2022] Open
Abstract
Obesity-associated low-grade inflammation favors weight gain, whereas systemic infection frequently leads to anorexia. Thus, inflammatory signals can either induce positive or negative energy balance. In this study, we used whole-cell patch-clamp to investigate the acute effects of three important proinflammatory cytokines, tumor necrosis factor α (TNF-α), interleukin-6, and interleukin-1β (IL-1β) on the membrane excitability of agouti-related peptide (AgRP)- or proopiomelanocortin (POMC)-producing neurons. We found that both TNF-α and IL-1β acutely inhibited the activity of 35-42% of AgRP-producing neurons, whereas very few POMC neurons were depolarized by TNF-α. Interleukin-6 induced no acute changes in the activity of AgRP or POMC neurons. Our findings indicate that the effect of TNF-α and IL-1β, especially on the activity of AgRP-producing neurons, may contribute to inflammation-induced anorexia observed during acute inflammatory conditions.
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Affiliation(s)
- Fernanda M. Chaves
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo 05508-000, Brazil;
| | - Naira S. Mansano
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo 05508-900, Brazil;
| | - Renata Frazão
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo 05508-900, Brazil;
- Correspondence: (R.F.); (J.D.J.)
| | - Jose Donato
- Departamento de Fisiologia e Biofísica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo 05508-000, Brazil;
- Correspondence: (R.F.); (J.D.J.)
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10
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Quaresma PGF, Dos Santos WO, Wasinski F, Metzger M, Donato J. Neurochemical phenotype of growth hormone-responsive cells in the mouse paraventricular nucleus of the hypothalamus. J Comp Neurol 2020; 529:1228-1239. [PMID: 32844436 DOI: 10.1002/cne.25017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022]
Abstract
Multiple neuroendocrine, autonomic and behavioral responses are regulated by the paraventricular nucleus of the hypothalamus (PVH). Previous studies have shown that PVH neurons express the growth hormone (GH) receptor (GHR), although the role of GH signaling on PVH neurons is still unknown. Given the great heterogeneity of cell types located in the PVH, we performed a detailed analysis of the neurochemical identity of GH-responsive cells to understand the possible physiological importance of GH action on PVH neurons. GH-responsive cells were detected via the phosphorylated form of the signal transducer and activator of transcription-5 (pSTAT5) in adult male mice that received an intraperitoneal GH injection. Approximately 51% of GH-responsive cells in the PVH co-localized with the vesicular glutamate transporter 2. Rare co-localizations between pSTAT5 and vesicular GABA transporter or vasopressin were observed, whereas approximately 20% and 38% of oxytocin and tyrosine hydroxylase (TH) cells, respectively, were responsive to GH in the PVH. Approximately 55%, 35% and 63% of somatostatin, thyrotropin-releasing hormone (TRH) and corticotropin-releasing hormone (CRH) neurons expressed GH-induced pSTAT5, respectively. Additionally, 8%, 49% and 75% of neuroendocrine TH, TRH and CRH neurons, and 67%, 32% and 74% of nonneuroendocrine TH, TRH and CRH neurons were responsive to GH in the PVH of Fluoro-Gold-injected mice. Our findings suggest that GH action on PVH neurons is involved in the regulation of the thyroid, somatotropic and adrenal endocrine axes, possibly influencing homeostatic and stress responses.
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Affiliation(s)
- Paula G F Quaresma
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Willian O Dos Santos
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Frederick Wasinski
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Martin Metzger
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
| | - Jose Donato
- Instituto de Ciências Biomédicas, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, São Paulo, Brazil
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11
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Campos AMP, Teixeira PDS, Wasinski F, Klein MO, Bittencourt JC, Metzger M, Donato J. Differences between rats and mice in the leptin action on the paraventricular nucleus of the hypothalamus: Implications for the regulation of the hypothalamic-pituitary-thyroid axis. J Neuroendocrinol 2020; 32:e12895. [PMID: 32840013 DOI: 10.1111/jne.12895] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/03/2020] [Accepted: 07/20/2020] [Indexed: 12/23/2022]
Abstract
Previous studies indicate that leptin regulates the hypothalamic-pituitary-thyroid (HPT) axis via direct and indirect mechanisms. The indirect mechanism involves leptin action in pro-opiomelanocortin (POMC)- and agouti-related peptide (AgRP)-expressing neurones. These cells innervate the paraventricular nucleus of the hypothalamus (PVH) where they modulate hypophysiotrophic thyrotrophin-releasing hormone (TRH)-producing neurones. The direct mechanism involves the expression of leptin receptor (LepR) in a subpopulation of PVH TRH neurones. However, to our knowledge, the existence of LepR in PVH TRH neurones of mice has not been clearly confirmed. Therefore, we investigated possible species-specific differences between rats and mice with respect to the mechanisms recruited by leptin to regulate the HPT axis. We observed that an acute leptin injection induced phosphorylated signal transducer and activator of transcription 3 (pSTAT3), a marker of leptin-responsive cells, in 46.2 ± 8.0% of PVH proTRH immunoreactive neurones in rats. By contrast, an insignificant number of proTRH positive neurones in the mouse PVH co-expressed leptin-induced pSTAT3 or LepR. Similarly, central leptin injection increased the percentage of PVH proTRH neurones containing cAMP response element-binding protein phosphorylation in rats, but not in mice. We investigated the innervation of AgRP and POMC axons in the PVH and observed that rats exhibited a denser POMC innervation in the PVH compared to mice, whereas rats and mice showed similar density of AgRP axons in the PVH. In conclusion, rats and mice exhibit important species-specific differences in the direct and indirect mechanisms used by leptin to regulate the HPT axis.
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Affiliation(s)
- Ana M P Campos
- Departamento de Fisiologia e Biofísica, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Pryscila D S Teixeira
- Departamento de Fisiologia e Biofísica, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Frederick Wasinski
- Departamento de Fisiologia e Biofísica, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Marianne O Klein
- Departamento de Anatomia, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Jackson C Bittencourt
- Departamento de Anatomia, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Martin Metzger
- Departamento de Fisiologia e Biofísica, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
| | - Jose Donato
- Departamento de Fisiologia e Biofísica, Universidade de Sao Paulo, Instituto de Ciencias Biomedicas, Sao Paulo, Brazil
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Beekly BG, Frankel WC, Berg T, Allen SJ, Garcia-Galiano D, Vanini G, Elias CF. Dissociated Pmch and Cre Expression in Lactating Pmch-Cre BAC Transgenic Mice. Front Neuroanat 2020; 14:60. [PMID: 32982701 PMCID: PMC7475711 DOI: 10.3389/fnana.2020.00060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/04/2020] [Indexed: 12/11/2022] Open
Abstract
The melanin-concentrating hormone (MCH) system plays a role in many physiological processes including reproduction and lactation. However, research regarding the function of MCH on different aspects of the reproductive function lags, due in part to a lack of validated genetic models with which to interrogate the system. This is particularly true in the case of female reproduction, as the anatomy and function of the MCH system is not well-characterized in the female mouse. We set out to determine whether the commercially available Pmch-Cre transgenic mouse line is a viable model to study the role of MCH neurons in distinct female reproductive states. We found that Pmch is transiently expressed in several nuclei of the rostral forebrain at the end of lactation. This includes the medial subdivision of the medial preoptic nucleus, the paraventricular nucleus of the hypothalamus, the ventral subdivision of the lateral septum, the anterodorsal preoptic nucleus and the anterodorsal nucleus of the thalamus. The Pmch expression in these sites, however, does not reliably induce Cre expression in the Pmch-Cre (BAC) transgenic mouse, making this line an inadequate model with which to study the role of MCH in behavioral and/or neuroendocrine adaptations of lactation. We also contribute to the general knowledge of the anatomy of the murine MCH system by showing that lactation-induced Pmch expression in the rostral forebrain is mostly observed in GABAergic (VGAT) neurons, in contrast to the typical MCH neurons of the tuberal and posterior hypothalamus which are glutamatergic (VGLUT2).
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Affiliation(s)
- Bethany G Beekly
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - William C Frankel
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States.,Baylor College of Medicine, Houston, TX, United States
| | - Tova Berg
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Susan J Allen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - David Garcia-Galiano
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Giancarlo Vanini
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Department of Anesthesiology, School of Medicine, University of Michigan, Ann Arbor, MI, United States
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States.,Department of Obstetrics and Gynecology, School of Medicine, University of Michigan, Ann Arbor, MI, United States
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