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González-García M, Carrillo-Franco L, Morales-Luque C, Ponce-Velasco M, Gago B, Dawid-Milner MS, López-González MV. Uncovering the neural control of laryngeal activity and subglottic pressure in anaesthetized rats: insights from mesencephalic regions. Pflugers Arch 2024; 476:1235-1247. [PMID: 38856775 PMCID: PMC11271367 DOI: 10.1007/s00424-024-02976-3] [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: 01/23/2024] [Revised: 04/15/2024] [Accepted: 05/21/2024] [Indexed: 06/11/2024]
Abstract
To assess the possible interactions between the dorsolateral periaqueductal gray matter (dlPAG) and the different domains of the nucleus ambiguus (nA), we have examined the pattern of double-staining c-Fos/FoxP2 protein immunoreactivity (c-Fos-ir/FoxP2-ir) and tyrosine hydroxylase (TH) throughout the rostrocaudal extent of nA in spontaneously breathing anaesthetised male Sprague-Dawley rats during dlPAG electrical stimulation. Activation of the dlPAG elicited a selective increase in c-Fos-ir with an ipsilateral predominance in the somatas of the loose (p < 0.05) and compact formation (p < 0.01) within the nA and confirmed the expression of FoxP2 bilaterally in all the domains within the nA. A second group of experiments was made to examine the importance of the dlPAG in modulating the laryngeal response evoked after electrical or chemical (glutamate) dlPAG stimulations. Both electrical and chemical stimulations evoked a significant decrease in laryngeal resistance (subglottal pressure) (p < 0.001) accompanied with an increase in respiratory rate together with a pressor and tachycardic response. The results of our study contribute to new data on the role of the mesencephalic neuronal circuits in the control mechanisms of subglottic pressure and laryngeal activity.
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Affiliation(s)
- M González-García
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain.
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, Málaga, Spain.
- IBIMA Plataforma BIONAND, Málaga, Spain.
| | - L Carrillo-Franco
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain
- IBIMA Plataforma BIONAND, Málaga, Spain
| | - C Morales-Luque
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain
| | - M Ponce-Velasco
- IBIMA Plataforma BIONAND, Málaga, Spain
- Department of Cell Biology, University of Málaga, Málaga, Spain
| | - B Gago
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain
- IBIMA Plataforma BIONAND, Málaga, Spain
| | - M S Dawid-Milner
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, Málaga, Spain
- IBIMA Plataforma BIONAND, Málaga, Spain
| | - M V López-González
- Department of Human Physiology, Faculty of Medicine, University of Málaga, Málaga, Spain.
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, Málaga, Spain.
- IBIMA Plataforma BIONAND, Málaga, Spain.
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Rocha I, González-García M, Carrillo-Franco L, Dawid-Milner MS, López-González MV. Influence of Brainstem's Area A5 on Sympathetic Outflow and Cardiorespiratory Dynamics. BIOLOGY 2024; 13:161. [PMID: 38534431 DOI: 10.3390/biology13030161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 03/28/2024]
Abstract
Area A5 is a noradrenergic cell group in the brain stem characterised by its important role in triggering sympathetic activity, exerting a profound influence on the sympathetic outflow, which is instrumental in the modulation of cardiovascular functions, stress responses and various other physiological processes that are crucial for adaptation and survival mechanisms. Understanding the role of area A5, therefore, not only provides insights into the basic functioning of the sympathetic nervous system but also sheds light on the neuronal basis of a number of autonomic responses. In this review, we look deeper into the specifics of area A5, exploring its anatomical connections, its neurochemical properties and the mechanisms by which it influences sympathetic nervous system activity and cardiorespiratory regulation and, thus, contributes to the overall dynamics of the autonomic function in regulating body homeostasis.
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Affiliation(s)
- Isabel Rocha
- Lisbon School of Medicine and CCUL@Rise, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Marta González-García
- Department of Human Physiology, Faculty of Medicine, University of Malaga, 29590 Malaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Malaga, 29590 Malaga, Spain
- Biomedical Research Institute of Malaga (IBIMA), 29590 Malaga, Spain
| | - Laura Carrillo-Franco
- Department of Human Physiology, Faculty of Medicine, University of Malaga, 29590 Malaga, Spain
- Biomedical Research Institute of Malaga (IBIMA), 29590 Malaga, Spain
| | - Marc Stefan Dawid-Milner
- Department of Human Physiology, Faculty of Medicine, University of Malaga, 29590 Malaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Malaga, 29590 Malaga, Spain
- Biomedical Research Institute of Malaga (IBIMA), 29590 Malaga, Spain
| | - Manuel Victor López-González
- Department of Human Physiology, Faculty of Medicine, University of Malaga, 29590 Malaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Malaga, 29590 Malaga, Spain
- Biomedical Research Institute of Malaga (IBIMA), 29590 Malaga, Spain
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González-García M, Carrillo-Franco L, Morales-Luque C, Dawid-Milner MS, López-González MV. Central Autonomic Mechanisms Involved in the Control of Laryngeal Activity and Vocalization. BIOLOGY 2024; 13:118. [PMID: 38392336 PMCID: PMC10886357 DOI: 10.3390/biology13020118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/07/2024] [Accepted: 02/10/2024] [Indexed: 02/24/2024]
Abstract
In humans, speech is a complex process that requires the coordinated involvement of various components of the phonatory system, which are monitored by the central nervous system. The larynx in particular plays a crucial role, as it enables the vocal folds to meet and converts the exhaled air from our lungs into audible sounds. Voice production requires precise and sustained exhalation, which generates an air pressure/flow that creates the pressure in the glottis required for voice production. Voluntary vocal production begins in the laryngeal motor cortex (LMC), a structure found in all mammals, although the specific location in the cortex varies in humans. The LMC interfaces with various structures of the central autonomic network associated with cardiorespiratory regulation to allow the perfect coordination between breathing and vocalization. The main subcortical structure involved in this relationship is the mesencephalic periaqueductal grey matter (PAG). The PAG is the perfect link to the autonomic pontomedullary structures such as the parabrachial complex (PBc), the Kölliker-Fuse nucleus (KF), the nucleus tractus solitarius (NTS), and the nucleus retroambiguus (nRA), which modulate cardiovascular autonomic function activity in the vasomotor centers and respiratory activity at the level of the generators of the laryngeal-respiratory motor patterns that are essential for vocalization. These cores of autonomic structures are not only involved in the generation and modulation of cardiorespiratory responses to various stressors but also help to shape the cardiorespiratory motor patterns that are important for vocal production. Clinical studies show increased activity in the central circuits responsible for vocalization in certain speech disorders, such as spasmodic dysphonia because of laryngeal dystonia.
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Affiliation(s)
- Marta González-García
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Laura Carrillo-Franco
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Carmen Morales-Luque
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
| | - Marc Stefan Dawid-Milner
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
| | - Manuel Víctor López-González
- Department of Human Physiology, Faculty of Medicine, University of Málaga, 29010 Málaga, Spain
- Unit of Neurophysiology of the Autonomic Nervous System (CIMES), University of Málaga, 29010 Málaga, Spain
- Biomedical Research Institute of Málaga (IBIMA Plataforma BIONAND), 29010 Málaga, Spain
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Impact of the glutamatergic neurotransmission within the A5 region on the cardiorespiratory response evoked from the midbrain dlPAG. Pflugers Arch 2023; 475:505-516. [PMID: 36543918 PMCID: PMC10011341 DOI: 10.1007/s00424-022-02777-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022]
Abstract
Stimulation of the dorsolateral periaqueductal grey matter (dlPAG) in rats evokes an active defensive behaviour together with a cardiorespiratory response characterised by tachypnoea, tachycardia and hypertension. The dlPAG neurons involved in these responses are excitatory, presumably glutamatergic, due to the presence of vesicular glutamate transporter VGLUT2 within their axon terminals. Previously, our group described a functional interaction between dlPAG and the pontine A5 region. Accordingly, in the present work, in order to characterize the role of glutamate within this interaction, experiments were carried out in spontaneously breathing anaesthetized rats (sodium pentobarbitone 60 mg/kg i.p., suplemented with 20 mg/kg i.p.). The cardiorespiratory response evoked by electrical stimulation of the dlPAG (1 ms pulses, 20-50 μA, given at 100 Hz, during 5 s) was analysed before and after the microinjection, within the A5 region, of either kynurenic acid (non-specific glutamate receptor antagonist; 5-10 nmol), DAP-5 (NMDA antagonist; 1 pmol), CNQX (non-NMDA antagonist; 1 pmol) or MCPG (metabotropic antagonist; 0,1 nmol). Kynurenic acid decreased the intensity of both the tachypnoea (p < 0,001) and tachycardia (p < 0,001) induced by dl-PAG stimulation. Blockade of no-NMDA receptors reduced the increase of respiratory frequency, heart rate and pressor response to dl-PAG stimulation (p < 0,01, p < 0,001, p < 0,05 respectively). Blockade of either NMDA or metabotropic receptors reduced the dlPAG-evoked tachycardia and pressor response (p < 0,01; p < 0,05 respectively). These results suggest a neuromodulatory role for A5 region via glutamate neurotransmission of the dlPAG-evoked cardiorespiratory response, confirming the role of the ventrolateral pons in the neuronal circuits involved in respiratory and heart rate control.
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