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Kawai F. Somatic ion channels and action potentials in olfactory receptor cells and vomeronasal receptor cells. J Neurophysiol 2024; 131:455-471. [PMID: 38264787 DOI: 10.1152/jn.00137.2023] [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: 04/02/2023] [Revised: 01/10/2024] [Accepted: 01/17/2024] [Indexed: 01/25/2024] Open
Abstract
Olfactory receptor cells are primary sensory neurons that catch odor molecules in the olfactory system, and vomeronasal receptor cells catch pheromones in the vomeronasal system. When odor or pheromone molecules bind to receptor proteins expressed on the membrane of the olfactory cilia or vomeronasal microvilli, receptor potentials are generated in their receptor cells. This initial excitation is transmitted to the soma via dendrites, and action potentials are generated in the soma and/or axon and transmitted to the central nervous system. Thus, olfactory and vomeronasal receptor cells play an important role in converting chemical signals into electrical signals. In this review, the electrophysiological characteristics of ion channels in the somatic membrane of olfactory receptor cells and vomeronasal receptor cells in various species are described and the differences between the action potential dynamics of olfactory receptor cells and vomeronasal receptor cells are compared.
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Affiliation(s)
- Fusao Kawai
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
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Hernandez-Clavijo A, Sánchez Triviño CA, Guarneri G, Ricci C, Mantilla-Esparza FA, Gonzalez-Velandia KY, Boscolo-Rizzo P, Tofanelli M, Bonini P, Dibattista M, Tirelli G, Menini A. Shedding light on human olfaction: Electrophysiological recordings from sensory neurons in acute slices of olfactory epithelium. iScience 2023; 26:107186. [PMID: 37456832 PMCID: PMC10345129 DOI: 10.1016/j.isci.2023.107186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/19/2023] [Accepted: 06/16/2023] [Indexed: 07/18/2023] Open
Abstract
The COVID-19 pandemic brought attention to our limited understanding of human olfactory physiology. While the cellular composition of the human olfactory epithelium is similar to that of other vertebrates, its functional properties are largely unknown. We prepared acute slices of human olfactory epithelium from nasal biopsies and used the whole-cell patch-clamp technique to record electrical properties of cells. We measured voltage-gated currents in human olfactory sensory neurons and supporting cells, and action potentials in neurons. Additionally, neuronal inward current and action potentials responses to a phosphodiesterase inhibitor suggested a transduction cascade involving cAMP as a second messenger. Furthermore, responses to odorant mixtures demonstrated that the transduction cascade was intact in this preparation. This study provides the first electrophysiological characterization of olfactory sensory neurons in acute slices of the human olfactory epithelium, paving the way for future research to expand our knowledge of human olfactory physiology.
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Affiliation(s)
- Andres Hernandez-Clavijo
- Neuroscience Area, SISSA, Scuola Internazionale Superiore di Studi Avanzati, 34136 Trieste, Italy
| | | | - Giorgia Guarneri
- Neuroscience Area, SISSA, Scuola Internazionale Superiore di Studi Avanzati, 34136 Trieste, Italy
| | - Chiara Ricci
- Neuroscience Area, SISSA, Scuola Internazionale Superiore di Studi Avanzati, 34136 Trieste, Italy
| | | | | | - Paolo Boscolo-Rizzo
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy
| | - Margherita Tofanelli
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy
| | - Pierluigi Bonini
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy
| | - Michele Dibattista
- Department of Translational Biomedicine and Neuroscience, University of Bari A. Moro, 70121 Bari, Italy
| | - Giancarlo Tirelli
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy
| | - Anna Menini
- Neuroscience Area, SISSA, Scuola Internazionale Superiore di Studi Avanzati, 34136 Trieste, Italy
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Ting CY, Shih CL, Yu MC, Wu CL, Wu SN. Characterization of Stimulatory Action on Voltage-Gated Na + Currents Caused by Omecamtiv Mecarbil, Known to Be a Myosin Activator. Biomedicines 2023; 11:biomedicines11051351. [PMID: 37239022 DOI: 10.3390/biomedicines11051351] [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: 03/02/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
Omecamtiv mecarbil (OM, CK-1827452) is recognized as an activator of myosin and has been demonstrated to be beneficial for the treatment of systolic heart failure. However, the mechanisms by which this compound interacts with ionic currents in electrically excitable cells remain largely unknown. The objective of this study was to investigate the effects of OM on ionic currents in GH3 pituitary cells and Neuro-2a neuroblastoma cells. In GH3 cells, whole-cell current recordings showed that the addition of OM had different potencies in stimulating the transient (INa(T)) and late components (INa(L)) of the voltage-gated Na+ current (INa) with different potencies in GH3 cells. The EC50 value required to observe the stimulatory effect of this compound on INa(T) or INa(L) in GH3 cells was found to be 15.8 and 2.3 µM, respectively. Exposure to OM did not affect the current versus voltage relationship of INa(T). However, the steady-state inactivation curve of the current was observed to shift towards a depolarized potential of approximately 11 mV, with no changes in the slope factor of the curve. The addition of OM resulted in an increase in the decaying time constant during the cumulative inhibition of INa(T) in response to pulse-train depolarizing stimuli. Furthermore, the presence of OM led to a shortening of the recovery time constant in the slow inactivation of INa(T). Adding OM also resulted in an augmentation of the strength of the window Na+ current, which was evoked by a short ascending ramp voltage. However, the OM exposure had little to no effect on the magnitude of L-type Ca2+ currents in GH3 cells. On the other hand, the delayed-rectifier K+ currents in GH3 cells were observed to be mildly suppressed in its presence. Neuro-2a cells also showed a susceptibility to the differential stimulation of INa(T) or INa(L) upon the addition of OM. Molecular analysis revealed potential interactions between the OM molecule and hNaV1.7 channels. Overall, the direct stimulation of INa(T) and INa(L) by OM is assumed to not be mediated by an interaction with myosin, and this has potential implications for its pharmacological or therapeutic actions occurring in vivo.
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Affiliation(s)
- Chih-Yu Ting
- Department of Emergency Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Chia-Lung Shih
- Clinical Research Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Meng-Cheng Yu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
| | - Chao-Liang Wu
- Clinical Research Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- School of Medicine, National Sun Yat-Sen University College of Medicine, Kaohsiung 80424, Taiwan
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