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Benites NM, Rodrigues B, da Silveira CH, Kushmerick C, Leao RM. Development of electrophysiological properties of fusiform neurons from the dorsal cochlear nucleus of mice before and after hearing onset. J Neurophysiol 2023. [PMID: 37222444 DOI: 10.1152/jn.00239.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
The dorsal cochlear nucleus (DCN) in the auditory brainstem integrates auditory and somatosensory information. Mature DCN fusiform neurons fall into two qualitatively distinct types: quiet, with no spontaneous regular action potential firing, or active, with regular spontaneous action potential firing. However, how these firing states and other electrophysiological properties of fusiform neurons develop during early post-natal days to adulthood is not known. Thus, we recorded fusiform neurons from mice from P4 to P21 and analyzed their electrophysiological properties. In the pre-hearing phase (P4-P13), we found that most fusiform neurons are quiet, with active neurons emerging after hearing onset at P14. Subthreshold properties underwent significant changes before hearing onset, whereas changes to the action potential waveform occurred mainly after P14, with the depolarization and repolarization phases becoming markedly faster and half-width significantly decreased. The activity threshold in post-hearing neurons was more negative than in pre-hearing cells. Persistent sodium current (INaP) was increased after P14, coinciding with the emergence of spontaneous firing. Thus, we suggest that post-hearing expression of INaP leads to hyperpolarization of the activity threshold and the active state of the fusiform neuron. At the same time, other changes refine the passive membrane properties and increase the speed of action potential firing of fusiform neurons.
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Affiliation(s)
- Nikollas Moreira Benites
- Department of Physiology, School of Medicine, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Beatriz Rodrigues
- Department of Physiology, School of Medicine, University of Sao Paulo, Ribeirao Preto, SP, Brazil
| | - Carlos H da Silveira
- Institute of Technological Sciences, Federal University of Itajubá, Itabira, MG, Brazil
| | - Christopher Kushmerick
- Department of Physiology and Biophysics, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte MG, Brazil
| | - Ricardo M Leao
- Department of Physiology, School of Medicine, University of Sao Paulo, Ribeirao Preto, SP, Brazil
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Cunha AOS, Moradi M, de Deus JL, Ceballos CC, Benites NM, de Barcellos Filho PCG, de Oliveira JAC, Garcia-Cairasco N, Leão R. Alterations in brainstem auditory processing, the acoustic startle response and sensorimotor gating of startle in Wistar audiogenic rats (WAR), an animal model of reflex epilepsies. Brain Res 2020; 1727:146570. [PMID: 31811837 DOI: 10.1016/j.brainres.2019.146570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/05/2019] [Accepted: 11/23/2019] [Indexed: 11/30/2022]
Abstract
While acute audiogenic seizures in response to acoustic stimulus appear as an alteration in sensory-motor processing in the brainstem, the repetition of the stimulus leads to the spread of epileptic activity to limbic structures. Here, we investigated whether animals of the Wistar Audiogenic Rat (WAR) strain, genetically selected by inbreeding for seizure susceptibility, would have alterations in their auditory response, assessed by the auditory brainstem responses (ABR) and sensory-motor gating, measured as pre-pulse inhibition (PPI), which could be related to their audiogenic seizures susceptibility or severity. We did not find differences between the amplitudes and latencies of ABR waves in response to clicks for WARs when compared to Wistars. Auditory gain and symmetry between ears were also similar. However, hearing thresholds in response to some tones were lower and amplitudes of wave II were larger in WARs. WARs had smaller acoustic startle reflex amplitudes and the percentages of startle inhibited by an acoustic prepulse were higher for WARs than for Wistars. However, no correlation was found between these alterations and brainstem-dependent seizure severity or limbic seizure frequency during audiogenic kindling. Our data show that while WARs present moderate alterations in primary auditory processing, the sensory motor gating measured in startle/PPI tests appears to be more drastically altered. The observed changes might be correlated with audiogenic seizure susceptibility but not seizures severity.
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Affiliation(s)
| | - Marzieh Moradi
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil; Department of Neuroscience and Behavioral Sciences, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Junia Lara de Deus
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Cesar Celis Ceballos
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Nikollas Moreira Benites
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | | | - Norberto Garcia-Cairasco
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ricardo Leão
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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de Barros NR, Heredia-Vieira SC, Borges FA, Benites NM, dos Reis CE, Miranda MCR, Cardoso CAL, Herculano RD. Natural rubber latex biodevice as controlled release system for chronic wounds healing. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aab33a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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