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Mota CMD, Madden CJ. Mediobasal hypothalamic neurons contribute to the control of brown adipose tissue sympathetic nerve activity and cutaneous vasoconstriction. J Therm Biol 2023; 114:103551. [PMID: 37216765 PMCID: PMC10330581 DOI: 10.1016/j.jtherbio.2023.103551] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/01/2023] [Accepted: 03/20/2023] [Indexed: 05/24/2023]
Abstract
The mediobasal hypothalamus (MBH) contains heterogeneous neuronal populations that regulate food intake and energy expenditure. However, the role of MBH neurons in the neural control of thermoeffector activity for thermoregulation is not known. This study sought to determine the effects of modulating the activity of MBH neurons on the sympathetic outflow to brown adipose tissue (BAT), BAT thermogenesis, and cutaneous vasomotion. Pharmacological inhibition of MBH neurons by local administration of muscimol, a GABAA receptor agonist, reduced skin cooling-evoked BAT thermogenesis, expired CO2, body temperature, heart rate, and mean arterial pressure, while blockade of GABAA receptors by nanoinjection of bicuculline in the MBH induced large increases in BAT sympathetic nerve activity (SNA), BAT temperature, body temperature, expired CO2, heart rate, and cutaneous vasoconstriction. Neurons in the MBH send projections to neurons in the dorsal hypothalamic area and dorsomedial hypothalamus (DMH), which excite sympathetic premotor neurons in the rostral raphe pallidus area (rRPa) that control sympathetic outflow to BAT. The increases in BAT SNA, BAT temperature, and expired CO2 elicited by blockade of GABAA receptors in the MBH were reversed by blocking excitatory amino acid receptors in the DMH or in the rRPa. Together, our data show that MBH neurons provide a modest contribution to BAT thermogenesis for cold defense, while GABAergic disinhibition of these neurons produces large increases in the sympathetic outflow to BAT, and cutaneous vasoconstriction. Activation of glutamate receptors on BAT thermogenesis-promoting neurons of the DMH and rRPa is necessary for the increased sympathetic outflow to BAT evoked by disinhibition of MBH neurons. These data demonstrate neural mechanisms that contribute to the control of thermoeffector activity, and may have important implications for regulating body temperature and energy expenditure.
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Affiliation(s)
- Clarissa M D Mota
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR, USA
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR, USA.
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Larsen LE, Lysebettens WV, Germonpré C, Carrette S, Daelemans S, Sprengers M, Thyrion L, Wadman WJ, Carrette E, Delbeke J, Boon P, Vonck K, Raedt R. Clinical Vagus Nerve Stimulation Paradigms Induce Pronounced Brain and Body Hypothermia in Rats. Int J Neural Syst 2016; 27:1750016. [PMID: 28178853 DOI: 10.1142/s0129065717500162] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Vagus nerve stimulation (VNS) is a widely used neuromodulation technique that is currently used or being investigated as therapy for a wide array of human diseases such as epilepsy, depression, Alzheimer's disease, tinnitus, inflammatory diseases, pain, heart failure and many others. Here, we report a pronounced decrease in brain and core temperature during VNS in freely moving rats. Two hours of rapid cycle VNS (7s on/18s off) decreased brain temperature by around [Formula: see text]C, while standard cycle VNS (30[Formula: see text]s on/300[Formula: see text]s off) was associated with a decrease of around [Formula: see text]C. Rectal temperature similarly decreased by more than [Formula: see text]C during rapid cycle VNS. The hypothermic effect triggered by VNS was further associated with a vasodilation response in the tail, which reflects an active heat release mechanism. Despite previous evidence indicating an important role of the locus coeruleus-noradrenergic system in therapeutic effects of VNS, lesioning this system with the noradrenergic neurotoxin DSP-4 did not attenuate the hypothermic effect. Since body and brain temperature affect most physiological processes, this finding is of substantial importance for interpretation of several previously published VNS studies and for the future direction of research in the field.
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Affiliation(s)
- Lars Emil Larsen
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Wouter Van Lysebettens
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Charlotte Germonpré
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Sofie Carrette
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Sofie Daelemans
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Mathieu Sprengers
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Lisa Thyrion
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Wytse Jan Wadman
- 2 Swammerdam Institute of Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, 1090GE, The Netherlands
| | - Evelien Carrette
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Jean Delbeke
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Paul Boon
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Kristl Vonck
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
| | - Robrecht Raedt
- 1 Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Department of Internal Medicine, Ghent University, De Pintelaan 185, Ghent, 9000, Belgium
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Schlenker EH. Sexual dimorphism of cardiopulmonary regulation in the arcuate nucleus of the hypothalamus. Respir Physiol Neurobiol 2016; 245:37-44. [PMID: 27756648 DOI: 10.1016/j.resp.2016.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/11/2016] [Accepted: 10/12/2016] [Indexed: 11/19/2022]
Abstract
The arcuate nucleus of the hypothalamus (ANH) interacts with other hypothalamic nuclei, forebrain regions, and downstream brain sites to affect autonomic nervous system outflow, energy balance, temperature regulation, sleep, arousal, neuroendocrine function, reproduction, and cardiopulmonary regulation. Compared to studies of other ANH functions, how the ANH regulates cardiopulmonary function is less understood. Importantly, the ANH exhibits structural and functional sexually dimorphic characteristics and contains numerous neuroactive substances and receptors including leptin, neuropeptide Y, glutamate, acetylcholine, endorphins, orexin, kisspeptin, insulin, Agouti-related protein, cocaine and amphetamine-regulated transcript, dopamine, somatostatin, components of renin-angiotensin system and gamma amino butyric acid that modulate physiological functions. Moreover, several clinically relevant disorders are associated with ANH ventilatory control dysfunction. This review highlights how ANH neurotransmitter systems and receptors modulate breathing differently in male and female rodents. Results highlight the significance of the ANH in cardiopulmonary regulation. The paucity of studies in this area that will hopefully spark investigations of sexually dimorphic ANH-modulation of breathing.
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Affiliation(s)
- Evelyn H Schlenker
- Division of Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, 414 East Clark St., Vermillion, SD, 57069, United States.
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