Banca de DEFESA: THAWANN MALFATTI BORGES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: THAWANN MALFATTI BORGES
DATA: 26/06/2015
HORA: 13:00
LOCAL: INSTITUTO DO CÉREBRO
TÍTULO:

VALIDATION OF OPTOGENETIC PROTEIN EXPRESSION IN THE DORSAL COCHLEAR NUCLEUS – MOLECULAR BASIS FOR IN VITRO AND IN VIVO INVESTIGATION OF TINNITUS IN MICE

 

 

 


PALAVRAS-CHAVES:
Optogenetics, Dorsal cochlear nucleus, Auditory system, Tinnitus

PÁGINAS: 60
GRANDE ÁREA: Ciências Biológicas
ÁREA: Fisiologia
RESUMO:

 

Tinnitus is the perception of a sound in the absence of a corresponding physical stimulus. It is not clear yet what mechanisms are involved in tinnitus and how it starts and/or becomes chronic. Due to the relationship between tinnitus and somatosensory trauma/stimuli, the dorsal cochlear nucleus (DCN), a region known to integrate somatosensory and auditory pathways, has been identified as a potential key structure in the generation of phantom sound perception. Here, we target specific neuronal populations in the DCN to allow further investigation on how this region may contribute to the generation of tinnitus signals that spread to other auditory areas. We examined the expression of optogenetic proteins (Channelrhodopsin 2 - ChR2; and enhanced Archaerhodopsin 3.0 - eArch3.0), targeting neurons expressing Calmoduline Kinase II alpha (CaMKIIa) promoter in wild-type C57/Bl6 mice and neurons expressing nicotinic acetylcholine receptor subunit alpha-2 promoter (ChRNA2) in ChRNA2- Cre transgenic C57/Bl6 mice, using local virus injection, verified by fluorescence microscopy. Unit responses were differentiated based on their electrophysiological response to sound. We then investigated if firing of neurons expressing optogenetic tools can be controlled in vivo and if the same neurons also fire action potentials in response to precisely timed sound stimulation. Both in vivo and preliminary in vitro data shows that neurons expressing ChR2 do respond to sound, and that they furthermore also can respond to light stimulation with a stable and similar waveform. Moreover, in vivo data shows that neurons expressing eArch3.0, responding to sound, will decrease their firing rate when exposed to green light. Thereby showing that optogenetic tools can be used functionally in the DCN, it is possible to further test tinnitus theories by, for example, producing an increased firing rate in the DCN, trying to mimic tinnitus; or inhibiting increased spontaneous firing rate in the DCN of animals with noise-induced or salycilate-induced tinnitus.


 


MEMBROS DA BANCA:
Presidente - 1976236 - EMELIE KATARINA SVAHN LEAO
Externo à Instituição - RICARDO MAURÍCIO XAVIER LEÃO - USP
Interno - 1824636 - RICHARDSON NAVES LEAO
Notícia cadastrada em: 12/06/2015 10:48
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