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Rein JL, Mackie K, Kleyman TR, Satlin LM. Cannabinoid receptor type 1 activation causes a water diuresis by inducing an acute central diabetes insipidus in mice. Am J Physiol Renal Physiol 2024; 326:F917-F930. [PMID: 38634131 DOI: 10.1152/ajprenal.00320.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
Cannabis and synthetic cannabinoid consumption are increasing worldwide. Cannabis contains numerous phytocannabinoids that act on the G protein-coupled cannabinoid receptor type 1 (CB1R) and cannabinoid receptor type 2 expressed throughout the body, including the kidney. Essentially every organ, including the kidney, produces endocannabinoids, which are endogenous ligands to these receptors. Cannabinoids acutely increase urine output in rodents and humans, thus potentially influencing total body water and electrolyte homeostasis. As the kidney collecting duct (CD) regulates total body water, acid/base, and electrolyte balance through specific functions of principal cells (PCs) and intercalated cells (ICs), we examined the cell-specific immunolocalization of CB1R in the mouse CD. Antibodies against either the C-terminus or N-terminus of CB1R consistently labeled aquaporin 2 (AQP2)-negative cells in the cortical and medullary CD and thus presumably ICs. Given the well-established role of ICs in urinary acidification, we used a clearance approach in mice that were acid loaded with 280 mM NH4Cl for 7 days and nonacid-loaded mice treated with the cannabinoid receptor agonist WIN55,212-2 (WIN) or a vehicle control. Although WIN had no effect on urinary acidification, these WIN-treated mice had less apical + subapical AQP2 expression in PCs compared with controls and developed acute diabetes insipidus associated with the excretion of large volumes of dilute urine. Mice maximally concentrated their urine when WIN and 1-desamino-8-d-arginine vasopressin [desmopressin (DDAVP)] were coadministered, consistent with central rather than nephrogenic diabetes insipidus. Although ICs express CB1R, the physiological role of CB1R in this cell type remains to be determined.NEW & NOTEWORTHY The CB1R agonist WIN55,212-2 induces central diabetes insipidus in mice. This research integrates existing knowledge regarding the diuretic effects of cannabinoids and the influence of CB1R on vasopressin secretion while adding new mechanistic insights about total body water homeostasis. Our findings provide a deeper understanding about the potential clinical impact of cannabinoids on human physiology and may help identify targets for novel therapeutics to treat water and electrolyte disorders such as hyponatremia and volume overload.
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Affiliation(s)
- Joshua L Rein
- Renal Section, Department of Medicine, James J. Peters Veterans Affairs Medical Center, Bronx, New York, United States
- Barbara T. Murphy Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Ken Mackie
- Gill Center for Biomolecular Medicine, Indiana University, Bloomington, Indiana, United States
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York, United States
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Korogod SM, Stern JE, Cymbalyuk GS. Microgeometrical dendritic factors predict electrical decoupling between somatic and dendritic compartments in magnocellular neurosecretory neurons. Front Cell Neurosci 2023; 17:1125029. [PMID: 37032839 PMCID: PMC10081025 DOI: 10.3389/fncel.2023.1125029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
It is generally assumed that dendritic release of neuropeptides from magnocellular neurosecretory neurons (MNNs), a critical process involved in homeostatic functions, is an activity-dependent process that requires backpropagating action potentials (APs). Still, growing evidence indicates that dendritic release can occur in the absence of APs, and axonal APs have been shown to fail to evoke dendritic release. These inconsistencies strongly suggest that APs in MNNs may fail to backpropagating into dendrites. Here we tested whether simple factors of electrical signal attenuation could lead to effective decoupling between cell's body and dendritic release site within typical geometrical characteristics of MNN. We developed a family of linear mathematical models of MNNs and evaluated whether the somato-dendritic transfer of electrical signals is influenced by the geometrical characteristics. We determined the prerequisites for critically strong dendritic attenuation of the somatic input which are sufficient to explain the failure of APs initiated in the soma to backpropagating into dendritic compartments. Being measured in 100 μm from soma voltage attenuations down to 0.1 and 0.01 of the input value were chosen as the markers of electrical decoupling of dendritic sites from the soma, considering 0.1 insufficient for triggering dendritic spikes and 0.01 indistinguishable from background noise. The tested micro-geometrical factors were the dendritic stem diameter, varicosities, and size of peri-dendritic space limited by glial sheath wrapping. Varicosities increased the attenuation along homogeneous proximal dendrites by providing an increased current leak at the junction with the proximal dendritic section. The glial sheath wrapping a dendrite section promoted greater attenuation by increasing longitudinal resistance of the interstitial peri-dendritic space thus playing the insulating role. These decoupling effects were strengthened in the case of the dendritic stems with thinner diameters of and/or increased conductivity of the membrane. These micro-geometrical factors are biophysically realistic and predict electrical decoupling between somatic and dendritic compartments in MNNs.
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Affiliation(s)
- Sergiy M. Korogod
- The Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Department of Molecular Biophysics, O. O. Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Javier E. Stern
- The Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA, United States
| | - Gennady S. Cymbalyuk
- The Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA, United States
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3
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Perkinson MR, Kirchner MK, Zhang M, Augustine RA, Stern JE, Brown CH. α-Melanocyte-stimulating hormone inhibition of oxytocin neurons switches to excitation in late pregnancy and lactation. Physiol Rep 2022; 10:e15226. [PMID: 35312181 PMCID: PMC8935534 DOI: 10.14814/phy2.15226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023] Open
Abstract
Oxytocin is secreted into the periphery by magnocellular neurons of the hypothalamic supraoptic and paraventricular nuclei (SON and PVN) to trigger uterine contraction during birth and milk ejection during suckling. Peripheral oxytocin secretion is triggered by action potential firing, which is regulated by afferent input activity and by feedback from oxytocin secreted into the extracellular space from magnocellular neuron somata and dendrites. A prominent input to oxytocin neurons arises from proopiomelanocortin neurons of the hypothalamic arcuate nucleus that secrete an alpha-melanocyte-stimulating hormone (α-MSH), which inhibits oxytocin neuron firing in non-pregnant rats by increasing somato-dendritic oxytocin secretion. However, α-MSH inhibition of oxytocin neuron firing is attenuated in mid-pregnancy and somato-dendritic oxytocin becomes auto-excitatory in late-pregnancy and lactation. Therefore, we hypothesized that attenuated α-MSH inhibition of oxytocin neuron firing marks the beginning of a transition from inhibition to excitation to facilitate peripheral oxytocin secretion for parturition and lactation. Intra-SON microdialysis administration of α-MSH inhibited oxytocin neuron firing rate by 33 ± 9% in non-pregnant rats but increased oxytocin neuron firing rate by 37 ± 12% in late-pregnant rats and by 28 ± 10% in lactating rats. α-MSH-induced somato-dendritic oxytocin secretion measured ex vivo with oxytocin receptor-expressing "sniffer" cells, was of similar amplitude in PVN slices from non-pregnant and lactating rats but longer-lasting in slices from lactating rats. Hence, α-MSH inhibition of oxytocin neuron activity switches to excitation over pregnancy while somato-dendritic oxytocin secretion is maintained, which might enhance oxytocin neuron excitability to facilitate the increased peripheral secretion that is required for normal parturition and milk ejection.
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Affiliation(s)
- Michael R. Perkinson
- Brain Health Research CentreUniversity of OtagoDunedinAotearoa New Zealand
- Centre for NeuroendocrinologyUniversity of OtagoDunedinAotearoa New Zealand
- Department of PhysiologyUniversity of OtagoDunedinAotearoa New Zealand
| | - Matthew K. Kirchner
- Center for Neuroinflammation and Cardiometabolic DiseasesGeorgia State UniversityAtlantaGeorgiaUSA
| | - Meng Zhang
- Center for Neuroinflammation and Cardiometabolic DiseasesGeorgia State UniversityAtlantaGeorgiaUSA
| | - Rachael A. Augustine
- Brain Health Research CentreUniversity of OtagoDunedinAotearoa New Zealand
- Centre for NeuroendocrinologyUniversity of OtagoDunedinAotearoa New Zealand
- Department of PhysiologyUniversity of OtagoDunedinAotearoa New Zealand
| | - Javier E. Stern
- Center for Neuroinflammation and Cardiometabolic DiseasesGeorgia State UniversityAtlantaGeorgiaUSA
| | - Colin H. Brown
- Brain Health Research CentreUniversity of OtagoDunedinAotearoa New Zealand
- Centre for NeuroendocrinologyUniversity of OtagoDunedinAotearoa New Zealand
- Department of PhysiologyUniversity of OtagoDunedinAotearoa New Zealand
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Brown CH, Ludwig M, Tasker JG, Stern JE. Somato-dendritic vasopressin and oxytocin secretion in endocrine and autonomic regulation. J Neuroendocrinol 2020; 32:e12856. [PMID: 32406599 PMCID: PMC9134751 DOI: 10.1111/jne.12856] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/29/2020] [Accepted: 04/11/2020] [Indexed: 12/29/2022]
Abstract
Somato-dendritic secretion was first demonstrated over 30 years ago. However, although its existence has become widely accepted, the function of somato-dendritic secretion is still not completely understood. Hypothalamic magnocellular neurosecretory cells were among the first neuronal phenotypes in which somato-dendritic secretion was demonstrated and are among the neurones for which the functions of somato-dendritic secretion are best characterised. These neurones secrete the neuropeptides, vasopressin and oxytocin, in an orthograde manner from their axons in the posterior pituitary gland into the blood circulation to regulate body fluid balance and reproductive physiology. Retrograde somato-dendritic secretion of vasopressin and oxytocin modulates the activity of the neurones from which they are secreted, as well as the activity of neighbouring populations of neurones, to provide intra- and inter-population signals that coordinate the endocrine and autonomic responses for the control of peripheral physiology. Somato-dendritic vasopressin and oxytocin have also been proposed to act as hormone-like signals in the brain. There is some evidence that somato-dendritic secretion from magnocellular neurosecretory cells modulates the activity of neurones beyond their local environment where there are no vasopressin- or oxytocin-containing axons but, to date, there is no conclusive evidence for, or against, hormone-like signalling throughout the brain, although it is difficult to imagine that the levels of vasopressin found throughout the brain could be underpinned by release from relatively sparse axon terminal fields. The generation of data to resolve this issue remains a priority for the field.
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Affiliation(s)
- Colin H. Brown
- Department of Physiology, Brain Health Research Centre, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Department of Immunology, Centre for Neuroendocrinology, University of Pretoria, Pretoria, South Africa
| | - Jeffrey G. Tasker
- Department of Cell and Molecular Biology, Brain Institute, Tulane University, New Orleans, LA, USA
| | - Javier E. Stern
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
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Social Stimuli Induce Activation of Oxytocin Neurons Within the Paraventricular Nucleus of the Hypothalamus to Promote Social Behavior in Male Mice. J Neurosci 2020; 40:2282-2295. [PMID: 32024781 DOI: 10.1523/jneurosci.1515-18.2020] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 01/20/2020] [Accepted: 01/23/2020] [Indexed: 01/09/2023] Open
Abstract
Oxytocin (OT) is critical for the expression of social behavior across a wide array of species; however, the role of this system in the encoding of socially relevant information is not well understood. In the present study, we show that chemogenetic activation of OT neurons within the paraventricular nucleus of the hypothalamus (PVH) of male mice (OT-Ires-Cre) enhanced social investigation during a social choice test, while chemogenetic inhibition of these neurons abolished typical social preferences. These data suggest that activation of the OT system is necessary to direct behavior preferentially toward social stimuli. To determine whether the presence of a social stimulus is sufficient to induce activation of PVH-OT neurons, we performed the first definitive recording of OT neurons in awake mice using two-photon calcium imaging. These recordings demonstrate that social stimuli activate PVH-OT neurons and that these neurons differentially encode social and nonsocial stimuli, suggesting that PVH-OT neurons may act to convey social salience of environmental stimuli. Finally, an attenuation of social salience is associated with social disorders, such as autism. We therefore also examined possible OT system dysfunction in a mouse model of autism, Shank3b knock-out (KO) mice. Male Shank3b KO mice showed a marked reduction in PVH-OT neuron number and administration of an OT receptor agonist improved social deficits. Overall, these data suggest that the presence of a social stimulus induces activation of the PVH-OT neurons to promote adaptive social behavior responses.SIGNIFICANCE STATEMENT Although the oxytocin (OT) system is well known to regulate a diverse array of social behaviors, the mechanism in which OT acts to promote the appropriate social response is poorly understood. One hypothesis is that the presence of social conspecifics activates the OT system to generate an adaptive social response. Here, we selectively recorded from OT neurons in the paraventricular hypothalamic nucleus (PVH) to show that social stimulus exposure indeed induces activation of the OT system. We also show that activation of the OT system is necessary to promote social behavior and that mice with abnormal social behavior have reduced numbers of PVH-OT neurons. Finally, aberrant social behavior in these mice was rescued by administration of an OT receptor agonist.
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Leng G, Russell JA. The osmoresponsiveness of oxytocin and vasopressin neurones: Mechanisms, allostasis and evolution. J Neuroendocrinol 2019; 31:e12662. [PMID: 30451331 DOI: 10.1111/jne.12662] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/29/2018] [Accepted: 11/15/2018] [Indexed: 12/27/2022]
Abstract
In the rat supraoptic nucleus, every oxytocin cell projects to the posterior pituitary, and is involved both in reflex milk ejection during lactation and in regulating uterine contractions during parturition. All are also osmosensitive, regulating natriuresis. All are also regulated by signals that control appetite, including the neural and hormonal signals that arise from the gut after food intake and from the sites of energy storage. All are also involved in sexual behaviour, anxiety-related behaviours and social behaviours. The challenge is to understand how a single population of neurones can coherently regulate such a diverse set of functions and adapt to changing physiological states. Their multiple functions arise from complex intrinsic properties that confer sensitivity to a wide range of internal and environmental signals. Many of these properties have a distant evolutionary origin in multifunctional, multisensory neurones of Urbilateria, the hypothesised common ancestor of vertebrates, insects and worms. Their properties allow different patterns of oxytocin release into the circulation from their axon terminals in the posterior pituitary into other brain areas from axonal projections, as well as independent release from their dendrites.
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Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - John A Russell
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
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Ladyman SR, Augustine RA, Scherf E, Phillipps HR, Brown CH, Grattan DR. Attenuated hypothalamic responses to α-melanocyte stimulating hormone during pregnancy in the rat. J Physiol 2016; 594:1087-101. [PMID: 26613967 DOI: 10.1113/jp271605] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/23/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Increased appetite and weight gain occurs during pregnancy, associated with development of leptin resistance, and satiety responses to the anorectic peptide α-melanocyte stimulating hormone (α-MSH) are suppressed. This study investigated hypothalamic responses to α-MSH during pregnancy, using c-fos expression in specific hypothalamic nuclei as a marker of neuronal signalling, and in vivo electrophysiology in supraoptic nucleus (SON) oxytocin neurons, as a representative α-MSH-responsive neuronal population that shows a well-characterised α-MSH-induced inhibition of firing. While icv injection of α-MSH significantly increased the number of c-fos-positive cells in the paraventricular, supraoptic, arcuate and ventromedial hypothalamic nuclei in non-pregnant rats, this response was suppressed in pregnant rats. Similarly, SON oxytocin neurons in pregnant rats did not demonstrate characteristic α-MSH-induced inhibition of firing that was observed in non-pregnant animals. Given the known functions of α-MSH in the hypothalamus, the attenuated responses are likely to facilitate adaptive changes in appetite regulation and oxytocin secretion during pregnancy. ABSTRACT During pregnancy, a state of positive energy balance develops to support the growing fetus and to deposit fat in preparation for the subsequent metabolic demands of lactation. As part of this maternal adaptation, the satiety response to the anorectic peptide α-melanocyte stimulating hormone (α-MSH) is suppressed. To investigate whether pregnancy is associated with changes in the response of hypothalamic α-MSH target neurons, non-pregnant and pregnant rats were treated with α-MSH or vehicle and c-fos expression in hypothalamic nuclei was then examined. Furthermore, the firing rate of supraoptic nucleus (SON) oxytocin neurons, a known α-MSH responsive neuronal population, was examined in non-pregnant and pregnant rats following α-MSH treatment. Intracerebroventricular injection of α-MSH significantly increased the number of c-fos-positive cells in the paraventricular, arcuate and ventromedial hypothalamic nuclei in non-pregnant rats, but no significant increase was observed in any of these regions in pregnant rats. In the SON, α-MSH did induce expression of c-fos during pregnancy, but this was significantly reduced compared to that observed in the non-pregnant group. Furthermore, during pregnancy, SON oxytocin neurons did not demonstrate the characteristic α-MSH-induced inhibition of firing rate that was observed in non-pregnant animals. Melanocortin receptor mRNA levels during pregnancy were similar to non-pregnant animals, suggesting that receptor down-regulation is unlikely to be a mechanism underlying the attenuated responses to α-MSH during pregnancy. Given the known functions of α-MSH in the hypothalamus, the attenuated responses will facilitate adaptive changes in appetite regulation and oxytocin secretion during pregnancy.
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Affiliation(s)
- S R Ladyman
- Department of Anatomy and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - R A Augustine
- Department of Physiology and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - E Scherf
- Department of Anatomy and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - H R Phillipps
- Department of Anatomy and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - C H Brown
- Department of Physiology and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - D R Grattan
- Department of Anatomy and Centre for Neuroendocrinology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
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Abstract
The posterior pituitary gland secretes oxytocin and vasopressin (the antidiuretic hormone) into the blood system. Oxytocin is required for normal delivery of the young and for delivery of milk to the young during lactation. Vasopressin increases water reabsorption in the kidney to maintain body fluid balance and causes vasoconstriction to increase blood pressure. Oxytocin and vasopressin secretion occurs from the axon terminals of magnocellular neurons whose cell bodies are principally found in the hypothalamic supraoptic nucleus and paraventricular nucleus. The physiological functions of oxytocin and vasopressin depend on their secretion, which is principally determined by the pattern of action potentials initiated at the cell bodies. Appropriate secretion of oxytocin and vasopressin to meet the challenges of changing physiological conditions relies mainly on integration of afferent information on reproductive, osmotic, and cardiovascular status with local regulation of magnocellular neurons by glia as well as intrinsic regulation by the magnocellular neurons themselves. This review focuses on the control of magnocellular neuron activity with a particular emphasis on their regulation by reproductive function, body fluid balance, and cardiovascular status. © 2016 American Physiological Society. Compr Physiol 6:1701-1741, 2016.
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Affiliation(s)
- Colin H Brown
- Brain Health Research Centre, Centre for Neuroendocrinology and Department of Physiology, University of Otago, Dunedin, New Zealand
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Abstract
Some of the earliest reports of the effects of cannabis consumption on humans were related to endocrine system changes. In this review, the effects of cannabinoids and the role of the CB1 cannabinoid receptor in the regulation of the following endocrine systems are discussed: the hypothalamic-pituitary-gonadal axis, prolactin and oxytocin, thyroid hormone and growth hormone, and the hypothalamic-pituitary-adrenal axis. Preclinical and human study results are presented.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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Stachniak TJ, Trudel E, Bourque CW. Cell-specific retrograde signals mediate antiparallel effects of angiotensin II on osmoreceptor afferents to vasopressin and oxytocin neurons. Cell Rep 2014; 8:355-62. [PMID: 25043186 DOI: 10.1016/j.celrep.2014.06.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 05/24/2014] [Accepted: 06/18/2014] [Indexed: 11/16/2022] Open
Abstract
Homeostatic control of extracellular fluid osmolality in rats requires a parallel excitation of vasopressin (VP) and oxytocin (OT) neurosecretory neurons by osmoreceptor afferents to regulate the amount of water and sodium in the urine under normal conditions. However, during decreased blood volume (hypovolemia), natriuresis is suppressed, whereas osmotically driven antidiuresis is enhanced to promote retention of isotonic fluid. Because Angiotensin II (Ang II) is released centrally to indicate hypovolemia, we hypothesized that Ang II can evoke a state-dependent switch in circuit function. Here, we show that Ang II, a neuropeptide released centrally during hypovolemia, suppresses osmoreceptor-mediated synaptic excitation of OT neurons while potentiating excitation of VP neurons. Ang II does this by inducing cell-autonomous release of nitric oxide by VP neurons and endocannabinoids by OT neurons to respectively enhance and reduce glutamate release by osmoreceptor afferents. These findings indicate that peptide modulators such as Ang II can regulate synaptic communication to achieve a state-dependent and target-specific modulation of circuit activity.
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Affiliation(s)
- Tevye J Stachniak
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, QC H3G1A4, Canada; Discovery Neuroscience, F. Hoffman-La Roche AG, Basel 4051, Switzerland
| | - Eric Trudel
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, QC H3G1A4, Canada
| | - Charles W Bourque
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal, QC H3G1A4, Canada.
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Makani V, Sultana R, Sie KS, Orjiako D, Tatangelo M, Dowling A, Cai J, Pierce W, Butterfield DA, Hill J, Park J. Annexin A1 complex mediates oxytocin vesicle transport. J Neuroendocrinol 2013; 25:1241-1254. [PMID: 24118254 PMCID: PMC3975805 DOI: 10.1111/jne.12112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 09/24/2013] [Accepted: 09/29/2013] [Indexed: 12/20/2022]
Abstract
Oxytocin is a major neuropeptide that modulates the brain functions involved in social behaviour and interaction. Despite of the importance of oxytocin for the neural control of social behaviour, little is known about the molecular mechanism(s) by which oxytocin secretion in the brain is regulated. Pro-oxytocin is synthesised in the cell bodies of hypothalamic neurones in the supraoptic and paraventricular nuclei and processed to a 9-amino-acid mature form during post-Golgi transport to the secretion sites at the axon terminals and somatodendritic regions. Oxytocin secreted from the somatodendritic regions diffuses throughout the hypothalamus and its neighbouring brain regions. Some oxytocin-positive axons innervate and secrete oxytocin to the brain regions distal to the hypothalamus. Brain oxytocin binds to its receptors in the brain regions involved in social behaviour. Oxytocin is also secreted from the axon terminal at the posterior pituitary gland into the blood circulation. We have discovered a new molecular complex consisting of annexin A1 (ANXA1), A-kinase anchor protein 150 (AKAP150) and microtubule motor that controls the distribution of oxytocin vesicles between the axon and the cell body in a protein kinase A (PKA)- and protein kinase C (PKC)-sensitive manner. ANXA1 showed significant co-localisation with oxytocin vesicles. Activation of PKA enhanced the association of kinesin-2 with ANXA1, thus increasing the axon-localisation of oxytocin vesicles. Conversely, activation of PKC decreased the binding of kinesin-2 to ANXA1, thus attenuating the axon-localisation of oxytocin vesicles. The result of the present study suggest that ANXA1 complex coordinates the actions of PKA and PKC to control the distribution of oxytocin vesicles between the axon and the cell body.
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Affiliation(s)
- Vishruti Makani
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Rukhsana Sultana
- Department of Chemistry, University of Kentucky, Lexington, KY 40506
| | - Khin Sander Sie
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Doris Orjiako
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Marco Tatangelo
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Abigail Dowling
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Jian Cai
- Department of Pharmacology, University of Louisville, Louisville, KY 40292
| | - William Pierce
- Department of Pharmacology, University of Louisville, Louisville, KY 40292
| | | | - Jennifer Hill
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Joshua Park
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
- To whom correspondence should be addressed. Department of Neurosciences, University of Toledo College of Medicine, Toledo, Ohio 43614, , Phone: (419) 383-4085, Fax: (419) 383-3008
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Romano A, Cassano T, Tempesta B, Cianci S, Dipasquale P, Coccurello R, Cuomo V, Gaetani S. The satiety signal oleoylethanolamide stimulates oxytocin neurosecretion from rat hypothalamic neurons. Peptides 2013; 49:21-6. [PMID: 23959001 DOI: 10.1016/j.peptides.2013.08.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 01/26/2023]
Abstract
The anandamide monounsaturated analogue oleoylethanolamide (OEA) acts as satiety signal released from enterocytes upon the ingestion of dietary fats to prolong the interval to the next meal. This effect, which requires intact vagal fibers and intestinal PPAR-alpha receptors, is coupled to the increase of c-fos and oxytocin mRNA expression in neurons of the paraventricular nucleus (PVN) and is prevented by the intracerebroventricular administration of a selective oxytocin antagonist, thus suggesting a necessary role of oxytocinergic neurotransmission in the pro-satiety effect of OEA. By brain microdialysis and immunohistochemistry, in this study we demonstrate that OEA treatment can stimulate oxytocin neurosecretion from the PVN and enhance oxytocin expression at both axonal and somatodendritic levels of hypothalamic neurons. Such effects, which are maximum 2h after OEA administration, support the hypothesis that the satiety-inducing action of OEA is mediated by the activation of oxytocin hypothalamic neurons.
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Affiliation(s)
- Adele Romano
- Department of Physiology and Pharmacology, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
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Schechter M, Weller A, Pittel Z, Gross M, Zimmer A, Pinhasov A. Endocannabinoid receptor deficiency affects maternal care and alters the dam's hippocampal oxytocin receptor and brain-derived neurotrophic factor expression. J Neuroendocrinol 2013; 25:898-909. [PMID: 23895426 DOI: 10.1111/jne.12082] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 07/10/2013] [Accepted: 07/24/2013] [Indexed: 01/12/2023]
Abstract
Maternal care is the newborn's first experience of social interaction, and this influences infant survival, development and social competences throughout life. We recently found that postpartum blocking of the endocannabinoid receptor-1 (CB1R) altered maternal behaviour. In the present study, maternal care was assessed by the time taken to retrieve pups, pups' ultrasonic vocalisations (USVs) and pup body weight, comparing CB1R deleted (CB1R KO) versus wild-type (WT) mice. After culling on postpartum day 8, hippocampal expression of oxytocin receptor (OXTR), brain-derived neurotrophic factor (BDNF) and stress-mediating factors were evaluated in CB1R KO and WT dams. Comparisons were also performed with nulliparous (NP) CB1R KO and WT mice. Compared to WT, CB1R KO dams were slower to retrieve their pups. Although the body weight of the KO pups did not differ from the weight of WT pups, they emitted fewer USVs. This impairment of the dam-pup relationship correlated with a significant reduction of OXTR mRNA and protein levels among CB1R KO dams compared to WT dams. Furthermore, WT dams exhibited elevated OXTR mRNA expression, as well as increased levels of mineralocorticoid and glucocorticoid receptors, compared to WT NP mice. By contrast, CB1R KO dams showed no such elevation of OXTR expression, alongside lower BDNF and mineralocorticoid receptors, as well as elevated corticotrophin-releasing hormone mRNA levels, when compared to CB1R KO NP. Thus, it appears that the disruption of endocannabinoid signalling by CB1R deletion alters expression of the OXTR, apparently leading to deleterious effects upon maternal behaviour.
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Affiliation(s)
- M Schechter
- Department of Molecular Biology, Ariel University, Ariel, Israel; Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel; Gonda Brain Research Center, Bar Ilan University, Ramat-Gan, Israel
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14
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Abstract
Oxytocin neurons have a physiological role in food intake and energy balance. Central administration of oxytocin is powerfully anorexigenic, reducing food intake and meal duration. The central mechanisms underlying this effect of oxytocin have become better understood in the past few years. Parvocellular neurons of the paraventricular nucleus project to the caudal brainstem to regulate feeding via autonomic functions including the gastrointestinal vago-vagal reflex. In contrast, magnocellular neurons of the supraoptic and paraventricular nuclei release oxytocin from their dendrites to diffuse to distant hypothalamic targets involved in satiety. The ventromedial hypothalamus, for example, expresses a high density of oxytocin receptors but does not contain detectable oxytocin nerve fibers. Magnocellular neurons represent targets for the anorexigenic neuropeptide α-melanocyte stimulating hormone. In addition to homeostatic control, oxytocin may also have a role in reward-related feeding. Evidence suggests that oxytocin can selectively suppress sugar intake and that it may have a role in limiting the intake of palatable food by inhibiting the reward pathway.
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Affiliation(s)
- Nancy Sabatier
- Centre for Integrative Physiology, School of Biomedical Sciences, The University of EdinburghEdinburgh, UK
| | - Gareth Leng
- Centre for Integrative Physiology, School of Biomedical Sciences, The University of EdinburghEdinburgh, UK
| | - John Menzies
- Centre for Integrative Physiology, School of Biomedical Sciences, The University of EdinburghEdinburgh, UK
- *Correspondence: John Menzies, Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh, EH8 9XD, UK. e-mail:
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Lawson EA, Holsen LM, Santin M, Meenaghan E, Eddy KT, Becker AE, Herzog DB, Goldstein JM, Klibanski A. Oxytocin secretion is associated with severity of disordered eating psychopathology and insular cortex hypoactivation in anorexia nervosa. J Clin Endocrinol Metab 2012; 97:E1898-908. [PMID: 22872688 PMCID: PMC3674290 DOI: 10.1210/jc.2012-1702] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Animal data suggest that oxytocin is a satiety hormone. We have demonstrated that anorexia nervosa (anorexia), a disorder characterized by food restriction, low weight, and hypoleptinemia, is associated with decreased nocturnal oxytocin secretion. We have also reported functional magnetic resonance imaging (fMRI) hypoactivation in anorexia in brain regions involved in food motivation. The relationships between oxytocin, food-motivation neurocircuitry, and disordered eating psychopathology have not been investigated in humans. OBJECTIVE The objective of the study was to determine whether the oxytocin response to feeding in anorexia differs from healthy women and to establish the relationship between oxytocin secretion and disordered eating psychopathology and food-motivation neurocircuitry. DESIGN This was a cross-sectional study. SETTING The study was conducted at a clinical research center. PARTICIPANTS Participants included 35 women: 13 anorexia (AN), nine weight-recovered anorexia (ANWR), and 13 healthy controls (HC). MEASURES Peripheral oxytocin and leptin levels were measured fasting and 30, 60, and 120 min after a standardized mixed meal. The Eating Disorder Examination-Questionnaire was used to assess disordered eating psychopathology. fMRI was performed during visual processing of food and nonfood stimuli to measure brain activation before and after the meal. RESULTS Mean oxytocin levels were higher in AN than HC at 60 and 120 min and lower in ANWR than HC at 0, 30, and 120 min and AN at all time points. Mean oxytocin area under the curve (AUC) was highest in AN, intermediate in HC, and lowest in ANWR. Mean leptin levels at all time points and AUC were lower in AN than HC and ANWR. Oxytocin AUC was associated with leptin AUC in ANWR and HC but not in AN. Oxytocin AUC was associated with the severity of disordered eating psychopathology in AN and ANWR, independent of leptin secretion, and was associated with between-group variance in fMRI activation in food motivation brain regions, including the hypothalamus, amygdala, hippocampus, orbitofrontal cortex, and insula. CONCLUSIONS Oxytocin may be involved in the pathophysiology of anorexia.
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Affiliation(s)
- Elizabeth A Lawson
- Neuroendocrine Unit, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, Massachusetts 02114, USA.
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Volume transmission of beta-endorphin via the cerebrospinal fluid; a review. Fluids Barriers CNS 2012; 9:16. [PMID: 22883598 PMCID: PMC3439317 DOI: 10.1186/2045-8118-9-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 07/07/2012] [Indexed: 02/08/2023] Open
Abstract
There is increasing evidence that non-synaptic communication by volume transmission in the flowing CSF plays an important role in neural mechanisms, especially for extending the duration of behavioral effects. In the present review, we explore the mechanisms involved in the behavioral and physiological effects of β-endorphin (β-END), especially those involving the cerebrospinal fluid (CSF), as a message transport system to reach distant brain areas. The major source of β-END are the pro-opio-melano-cortin (POMC) neurons, located in the arcuate hypothalamic nucleus (ARH), bordering the 3rd ventricle. In addition, numerous varicose β-END-immunoreactive fibers are situated close to the ventricular surfaces. In the present paper we surveyed the evidence that volume transmission via the CSF can be considered as an option for messages to reach remote brain areas. Some of the points discussed in the present review are: release mechanisms of β-END, independence of peripheral versus central levels, central β-END migration over considerable distances, behavioral effects of β-END depend on location of ventricular administration, and abundance of mu and delta opioid receptors in the periventricular regions of the brain.
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17
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G protein-coupled receptors in the hypothalamic paraventricular and supraoptic nuclei--serpentine gateways to neuroendocrine homeostasis. Front Neuroendocrinol 2012; 33:45-66. [PMID: 21802439 PMCID: PMC3336209 DOI: 10.1016/j.yfrne.2011.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/24/2011] [Accepted: 07/06/2011] [Indexed: 12/31/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in the mammalian genome. They are activated by a multitude of different ligands that elicit rapid intracellular responses to regulate cell function. Unsurprisingly, a large proportion of therapeutic agents target these receptors. The paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus are important mediators in homeostatic control. Many modulators of PVN/SON activity, including neurotransmitters and hormones act via GPCRs--in fact over 100 non-chemosensory GPCRs have been detected in either the PVN or SON. This review provides a comprehensive summary of the expression of GPCRs within the PVN/SON, including data from recent transcriptomic studies that potentially expand the repertoire of GPCRs that may have functional roles in these hypothalamic nuclei. We also present some aspects of the regulation and known roles of GPCRs in PVN/SON, which are likely complemented by the activity of 'orphan' GPCRs.
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18
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Menzies JRW, Skibicka KP, Dickson SL, Leng G. Neural substrates underlying interactions between appetite stress and reward. Obes Facts 2012; 5:208-20. [PMID: 22647303 DOI: 10.1159/000338237] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/16/2011] [Indexed: 12/21/2022] Open
Abstract
Neurobiological mechanisms that normally control food intake and energy expenditure can be overcome by environmental cues and by stress. Of particular importance is the influence of the mesolimbic reward pathway. In genetically susceptible individuals, problematic over-eating likely reflects a changing balance in the control exerted by homeostatic versus reward circuits that are strongly influenced by environmental factors such as stress. Both stress and activation of the reward pathway have been shown to increase food intake and promote a preference for palatable, high-energy foods. Recent research has focused on the important role of circulating and central neuropeptides that powerfully regulate the brain response to food cues. For example, ghrelin has a potent positive effect on the motivational aspects of food intake, and central oxytocin may be involved in satiety. Thus, the decision to eat, or indeed to over-eat, involves a complex integrated neurobiology that includes brain centres involved in energy balance, reward and stress and their regulation by metabolic and endocrine factors.
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Affiliation(s)
- John R W Menzies
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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19
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20
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Opposing actions of endothelin-1 on glutamatergic transmission onto vasopressin and oxytocin neurons in the supraoptic nucleus. J Neurosci 2011; 30:16855-63. [PMID: 21159956 DOI: 10.1523/jneurosci.5079-10.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Endothelin (ET-1) given centrally has many reported actions on hormonal and autonomic outputs from the CNS. However, it is unclear whether these effects are due to local ischemia via its vasoconstrictor properties or to a direct neuromodulatory action. ET-1 stimulates the release of oxytocin (OT) and vasopressin (VP) from supraoptic magnocellular (MNCs) neurons in vivo; therefore, we asked whether ET-1 modulates the excitatory inputs onto MNCs that are critical in sculpting the activity of these neurons. To investigate whether ET-1 modulates excitatory synaptic transmission, we obtained whole-cell recordings and analyzed quantal glutamate release onto MNCs in the supraoptic nucleus (SON). Neurons identified as VP-containing neurosecretory cells displayed a decrease in quantal frequency in response to ET-1 (10-100 pm). This decrease was mediated by ET(A) receptor activation and production of a retrograde messenger that targets presynaptic cannabinoid-1 receptors. In contrast, neurons identified as OT-containing MNCs displayed a transient increase in quantal glutamate release in response to ET-1 application via ET(B) receptor activation. Application of TTX to block action potential-dependent glutamate release inhibited the excitatory action of ET-1 in OT neurons. There were no changes in quantal amplitude in either MNC type, suggesting that the effects of ET-1 were via presynaptic mechanisms. A gliotransmitter does not appear to be involved as ET-1 failed to elevate astrocytic calcium in the SON. Our results demonstrate that ET-1 differentially modulates glutamate release onto VP- versus OT-containing MNCs, thus implicating it in the selective regulation of neuroendocrine output from the SON.
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21
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Gorzalka BB, Hill MN, Chang SCH. Male-female differences in the effects of cannabinoids on sexual behavior and gonadal hormone function. Horm Behav 2010; 58:91-9. [PMID: 19733173 DOI: 10.1016/j.yhbeh.2009.08.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 08/18/2009] [Accepted: 08/26/2009] [Indexed: 11/19/2022]
Abstract
The putative role of the endocannabinoid system and the effects of cannabis use in male and female sexual functioning are summarized. The influence of cannabis intake on sexual behavior and arousability appear to be dose-dependent in both men and women, although women are far more consistent in reporting facilitatory effects. Furthermore, evidence from nonhuman species indicate somewhat more beneficial than debilitating effects of cannabinoids on female sexual proceptivity and receptivity while suggesting predominantly detrimental effects on male sexual motivation and erectile functioning. Data from human and nonhuman species converge on the ephemeral nature of THC-induced testosterone decline. However, it is clear that cannabinoid-induced inhibition of male sexual behavior is independent of concurrent declines in testosterone levels. Investigations also reveal a suppression of gonadotropin release by cannabinoids across various species. Historical milestones and promising future directions in the area of cannabinoid and sexuality research are also outlined in this review.
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Affiliation(s)
- Boris B Gorzalka
- Department of Psychology, University of British Columbia, Vancouver, Canada, BC V6T 1Z4.
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22
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The hypothalamic endocannabinoid system participates in the secretion of oxytocin and tumor necrosis factor-alpha induced by lipopolysaccharide. J Neuroimmunol 2010; 221:32-41. [DOI: 10.1016/j.jneuroim.2010.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 02/04/2010] [Accepted: 02/04/2010] [Indexed: 01/21/2023]
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23
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Baskerville TA, Allard J, Wayman C, Douglas AJ. Dopamineâoxytocin interactions in penile erection. Eur J Neurosci 2009; 30:2151-64. [DOI: 10.1111/j.1460-9568.2009.06999.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Ross HE, Young LJ. Oxytocin and the neural mechanisms regulating social cognition and affiliative behavior. Front Neuroendocrinol 2009; 30:534-547. [PMID: 19481567 PMCID: PMC2748133 DOI: 10.1016/j.yfrne.2009.05.004] [Citation(s) in RCA: 535] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 05/14/2009] [Accepted: 05/22/2009] [Indexed: 12/17/2022]
Abstract
Oxytocin is produced in the hypothalamus and released into the circulation through the neurohypophyseal system. Peripherally released oxytocin facilitates parturition and milk ejection during nursing. Centrally released oxytocin coordinates the onset of maternal nurturing behavior at parturition and plays a role in mother-infant bonding. More recent studies have revealed a more general role for oxytocin in modulating affiliative behavior in both sexes. Oxytocin regulates alloparental care and pair bonding in female monogamous prairie voles. Social recognition in male and female mice is also modulated by oxytocin. In humans, oxytocin increases gaze to the eye region of human faces and enhances interpersonal trust and the ability to infer the emotions of others from facial cues. While the neurohypopheseal oxytocin system has been well characterized, less is known regarding the nature of oxytocin release within the brain. Here we review the role of oxytocin in the regulation of prosocial interactions, and discuss the neuroanatomy of the central oxytocin system.
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Affiliation(s)
- Heather E Ross
- Center for Behavioral Neuroscience, Yerkes National Primate Research Center, Atlanta GA, USA
| | - Larry J Young
- Center for Behavioral Neuroscience, Yerkes National Primate Research Center, Atlanta GA, USA; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA.
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25
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López HH, Webb SA, Nash S. Cannabinoid receptor antagonism increases female sexual motivation. Pharmacol Biochem Behav 2009; 92:17-24. [DOI: 10.1016/j.pbb.2008.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 10/07/2008] [Accepted: 10/13/2008] [Indexed: 01/23/2023]
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26
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Saito T, Dayanithi G, Saito J, Onaka T, Urabe T, Watanabe TX, Hashimoto H, Yokoyama T, Fujihara H, Yokota A, Nishizawa S, Hirata Y, Ueta Y. Chronic osmotic stimuli increase salusin-beta-like immunoreactivity in the rat hypothalamo-neurohypophyseal system: possible involvement of salusin-beta on [Ca2+]i increase and neurohypophyseal hormone release from the axon terminals. J Neuroendocrinol 2008; 20:207-19. [PMID: 18047553 DOI: 10.1111/j.1365-2826.2007.01632.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Salusin-alpha and -beta were recently discovered as bioactive endogenous peptides. In the present study, we investigated the effects of chronic osmotic stimuli on salusin-beta-like immunoreactivity (LI) in the rat hypothalamo-neurohypophyseal system. We examined the effects of salusin-beta on synaptic inputs to the rat magnocellular neurosecretory cells (MNCs) of the supraoptic nucleus (SON) and neurohypophyseal hormone release from both freshly dissociated SONs and neurohypophyses in rats. Immunohistochemical studies revealed that salusin-beta-LI neurones and fibres were markedly increased in the SON and the magnocellular division of the paraventricular nucleus after chronic osmotic stimuli resulting from salt loading for 5 days and dehydration for 3 days. Salusin-beta-LI fibres and varicosities in the internal zone of the median eminence and the neurohypophysis were also increased after osmotic stimuli. Whole-cell patch-clamp recordings from rat SON slice preparations showed that salusin-beta did not cause significant changes in the excitatory and inhibitory postsynaptic currents of the MNCs. In vitro hormone release studies showed that salusin-beta evoked both arginine vasopressin (AVP) and oxytocin release from the neurohypophysis, but not the SON. In our hands, in the neurohypophysis, a significant release of AVP and oxytocin was observed only at concentrations from 100 nm and above of salusin-beta. Low concentrations below 100 nm were ineffective both on AVP and oxytocin release. We also measured intracellular calcium ([Ca(2+)](i)) increase induced by salusin-beta on freshly-isolated single nerve terminals from the neurohypophysis devoid of pars intermedia. Furthermore, this salusin-beta-induced [Ca(2+)](i) increase was blocked in the presence of high voltage activated Ca(2+)channel blockers. Our results suggest that salusin-beta may be involved in the regulation of body fluid balance by stimulating neurohypophyseal hormone release from nerve endings by an autocrine/paracrine mechanism.
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Affiliation(s)
- T Saito
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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27
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Endogenous modulators of synaptic transmission: cannabinoid regulation in the supraoptic nucleus. PROGRESS IN BRAIN RESEARCH 2008; 170:129-36. [PMID: 18655878 PMCID: PMC3569497 DOI: 10.1016/s0079-6123(08)00412-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The magnocellular neurons of the hypothalamic supraoptic nucleus (SON) are a major source of both systemic and central release of the neurohypophyseal peptides, oxytocin (OXT) and arginine-vasopressin (AVP). Both OXT and AVP are released from the somatodendritic compartment of magnocellular neurons and act within the SON to modulate the electrophysiological function of these cells. Cannabinoids (CBs) affect hormonal output and the SON may represent a neural substrate through which CBs exert specific physiological and behavioural effects. Dynamic modulation of synaptic inputs is a fundamental mechanism through which neuronal output is controlled. Dendritically released OXT acts on autoreceptors to generate endocannabinoids (eCBs) which modify both excitatory and inhibitory inputs to OXT neurons through actions on presynaptic CB receptors. As such, OXT and eCBs cooperate to shape the electrophysiological properties of magnocellular OXT neurons, regulating the physiological function of this nucleus. Further study of eCB signalling in the SON, including its interaction with AVP neurons, promises to extend our understanding of the synaptic regulation of SON physiological function.
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28
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Ji LL, Gottlieb HB, Penny ML, Fleming T, Toney GM, Cunningham JT. Differential effects of water deprivation and rehydration on Fos and FosB/DeltaFosB staining in the rat brainstem. Exp Neurol 2006; 203:445-56. [PMID: 17027755 DOI: 10.1016/j.expneurol.2006.08.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 08/24/2006] [Accepted: 08/28/2006] [Indexed: 11/27/2022]
Abstract
This study examined the effects of dehydration and rehydration with water on Fos and FosB staining in the brainstem of rats. Male rats were water deprived for 48 h (Dehyd, n=7) or 46 h followed by 2 h access to water (Rehyd, n=7). Controls had ad libitum access to water (Con, n=9). Brainstems were stained for Fos and FosB/DeltaFosB using commercially available antibodies. In the nucleus of the solitary tract (NTS), the number of Fos stained neurons was significantly increased by dehydration and increased further following rehydration (Con 5+/-1; Dehyd 22+/-1; Rehyd 48+/-5). The average number of Fos-positive cells in the parabrachial nucleus (PBN) was significantly increased only by rehydration (Con 12+/-2; Dehyd 6+/-2; Rehyd 51+/-4). The area postrema (AP) showed significant increases in Fos staining after dehydration and rehydration (Fos: Con 4+/-1; Dehyd 28+/-3; Rehyd 24+/-3). In the rostral ventrolateral medulla (RVL), Fos staining significantly increased after dehydration and this effect was reduced by rehydration (Con 3+/-1; Dehyd 21+/-2; Rehyd 12+/-1). In contrast, Fos staining in the caudal ventrolateral medulla (CVL) was not significantly influenced following either dehydration or rehydration with water (Con 4+/-1; Dehyd 4+/-1; Rehyd 5+/-1). FosB/DeltaFosB staining in the NTS, AP, and RVL was comparably increased by dehydration and rehydration. In the PBN and CVL, FosB/DeltaFosB staining was not affected by the treatments. Dehydration and rehydration have regionally specific effects on Fos and FosB/DeltaFosB staining in the brainstem.
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Affiliation(s)
- Lisa L Ji
- Department of Pharmacology, and the Center for Biomedical Neuroscience, UTHSCSA, USA
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29
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Sheynzon P, Korf HW. Targeted deletions of Mel1a and Mel1b melatonin receptors affect pCREB levels in lactotroph and pars intermedia cells of mice. Neurosci Lett 2006; 407:48-52. [PMID: 16959416 DOI: 10.1016/j.neulet.2006.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 07/31/2006] [Accepted: 08/01/2006] [Indexed: 11/17/2022]
Abstract
The actions of the pineal hormone melatonin depend on two types of membrane-bound, G-protein-coupled receptors: the MT1 (Mel1a) and MT2 (Mel1b) melatonin receptors. An important target of melatonin is the hypophysial pars tuberalis that controls the activity of lactotroph cells in the pars distalis (PD). To identify the melatonin receptor type responsible for regulation of the lactotroph cells in pars distalis we studied the levels of Ser133-phosphorylated pCREB in immunocytochemically identified lactotroph cells of wild-type mice (MelAABB) and of mice bearing targeted deletions of the Mel1a receptor (MelaaBB), the Mel1b receptor (MelAAbb) or of both receptor types (Melaabb) at five different time points of a light/dark cycle. Moreover, we analyzed whether pCREB levels in pars intermedia cells also depend on intact melatonin signal transduction cascades. In wild type and MelAAbb mice the percentage of lactotroph cells with nuclear pCREB immunoreactions varied significantly over a 24 h period, whereas in MelaaBB and Melaabb mice no significant differences were found between the five time points analyzed. pCREB levels in the pars intermedia did not show rhythmic variation in wild type or Melaabb animals but wild type mice had higher pCREB levels than Melaabb. Our results indicate that Mel1a and Mel1b melatonin receptors are involved in the control of the activity state of lactotroph and pars intermedia cells of mice.
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Affiliation(s)
- Pjotr Sheynzon
- Dr. Senckenbergische Anatomie, Institut für Anatomie II, Fachbereich Medizin der J.W. Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany
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30
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Johnstone LE, Fong TM, Leng G. Neuronal activation in the hypothalamus and brainstem during feeding in rats. Cell Metab 2006; 4:313-21. [PMID: 17011504 DOI: 10.1016/j.cmet.2006.08.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 07/06/2006] [Accepted: 08/08/2006] [Indexed: 10/24/2022]
Abstract
We trained rats to a regime of scheduled feeding, in which food was available for only 2 hr each day. After 10 days, rats were euthanized at defined times relative to food availability, and their brains were analyzed to map Fos expression in neuronal populations to test the hypothesis that some populations are activated by hunger whereas others are activated by satiety signals. Fos expression accompanied feeding in several hypothalamic and brainstem nuclei. Food ingestion was critical for Fos expression in noradrenergic and non-noradrenergic cells in the nucleus tractus solitarii and area postrema and in the supraoptic nucleus, as well as in melanocortin-containing cells of the arcuate nucleus. However, anticipation of food alone activated other neurons in the arcuate nucleus and in the lateral and ventromedial hypothalamus, including orexin neurons. Thus orexigenic populations are strongly and rapidly activated at the onset of food presentation, followed rapidly by activity in anorexigenic populations when food is ingested.
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Affiliation(s)
- Louise E Johnstone
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, United Kingdom.
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31
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Malcher-Lopes R, Di S, Marcheselli VS, Weng FJ, Stuart CT, Bazan NG, Tasker JG. Opposing crosstalk between leptin and glucocorticoids rapidly modulates synaptic excitation via endocannabinoid release. J Neurosci 2006; 26:6643-50. [PMID: 16775153 PMCID: PMC6674033 DOI: 10.1523/jneurosci.5126-05.2006] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) integrates preautonomic and neuroendocrine control of energy homeostasis, fluid balance, and the stress response. We recently demonstrated that glucocorticoids act via a membrane receptor to rapidly cause endocannabinoid-mediated suppression of synaptic excitation in PVN neurosecretory neurons. Leptin, a major signal of nutritional state, suppresses CB(1) cannabinoid receptor-dependent hyperphagia (increased appetite) in fasting animals by reducing hypothalamic levels of endocannabinoids. Here we show that glucocorticoids stimulate endocannabinoid biosynthesis and release via a Galpha(s)-cAMP-protein kinase A-dependent mechanism and that leptin blocks glucocorticoid-induced endocannabinoid biosynthesis and suppression of excitation in the PVN via a phosphodiesterase-3B-mediated reduction in intracellular cAMP levels. We demonstrate this rapid hormonal interaction in both PVN magnocellular and parvocellular neurosecretory cells. Leptin blockade of the glucocorticoid-induced, endocannabinoid-mediated suppression of excitation was absent in leptin receptor-deficient obese Zucker rats. Our findings reveal a novel hormonal crosstalk that rapidly modulates synaptic excitation via endocannabinoid release in the hypothalamus and that provides a nutritional state-sensitive mechanism to integrate the neuroendocrine regulation of energy homeostasis, fluid balance, and the stress response.
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Armstrong WE, Hatton GI. The puzzle of pulsatile oxytocin secretion during lactation: some new pieces. Am J Physiol Regul Integr Comp Physiol 2006; 291:R26-8. [PMID: 16832903 DOI: 10.1152/ajpregu.00879.2005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- William E Armstrong
- Department of Anatomy and Neurobiology, Unversity of Tennessee Medical School, Memphis, Tennessee 38163, USA.
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