Expression of the neuron-specific potassium chloride cotransporter KCC2 in adult rat cochlear.
Auditory transduction in the cochlear is subject to modulate higher auditory centers in the brain via the efferent systems, which provide protection against damage caused by excessive excitation during auditory over stimulation. GABA is a proven inhibitory neurotransmitter in the efferent systems in mammalian cochlear. KCC2 is a neuron-specific potassium chloride cotransporter whose role in mature central neurons is to maintain the low intracellular Cl(-) concentrations required for the hyperpolarizing responses to the inhibitory amino acids GABA and glycine. However, there is a lack of information concerning KCC2 expression in the mammalian cochlear. In this study, reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were used to detect the expression and localization of KCC2 in the mammalian cochlear. The results showed that these neuron-specific KCC2 transporters were present in most spiral ganglion neurons (SGNs) corresponding to the distribution of GABA(A)Rs. In addition, less intense reactions were observed on the organ of Corti, stria vascularis, and fibrocytes of the spiral ligament. These data suggest that KCC2 may play an important role in the modulation of a GABA neurotransmitter's function in a mammalian cochlear. Moreover, the presence of KCC2 on the organ of Corti and its surrounding tissues may contribute to maintaining normal K+ cycling. It is also presumed to be related to Cl(-) transportation in hair cells.
Yang
Kun
K
Department of Otolaryngology-Head & Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, People's Republic of China.
Huang
Zhi-Wu
ZW
Huang
Juan
J
Zhang
Xiao-Jun
XJ
Xiao
Bo-Kui
BK
D000818:Animals; D015870:Gene Expression / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism; D013136:Spiral Ganglion / Q000166:cytology*; D027981:Symporters / Q000235:genetics / Q000378:metabolism*; D000096922:K Cl- Cotransporters
D012333:RNA, Messenger; D011963:Receptors, GABA-A; D027981:Symporters; D000096922:K Cl- Cotransporters