TY - JOUR
T1 - Development of acetylcholine receptors in cultured outer hair cells
AU - He, David Z.Z.
AU - Zheng, Jing
AU - Dallos, Peter
N1 - Funding Information:
This work has been supported by a grant from the Deafness Research Foundation and by NIH Grants R01 DC 04696 to D.H., R01 DC 00708 to P.D. from the National Institute of Deafness and Other Communication Disorders. We thank Mr. Kevin Long for some technical assistance.
PY - 2001
Y1 - 2001
N2 - Efferents, originating in the superior olivary complex, preferentially synapse with cochlear outer hair cells (OHCs), with acetylcholine (ACh) as their primary neurotransmitter. The OHC ACh receptors (AChRs), which have unusual pharmacology, have been cloned and identified as a new subunit (α9) of the nicotinic AChR family. The expression of α9 AChRs is first detected before birth and peaks between 6 and 10 days after birth (DAB) in developing mice and rats, while functional maturation of the receptor, as determined by measuring the ACh-induced currents, takes place between 6 and 12 DAB. In this study we attempted to examine the development of AChRs in OHCs grown in explanted cultures, deprived of efferent innervation. ACh-induced currents were used as an assay. Reverse transcription-PCR analysis was also performed to detect the expression of α9 subunit from cultured OHCs. PCR study indicates that mRNA of the α9 subunit was expressed in primary cochlear cultures, similar to that seen in the cochleae of developing animals. Measurement of whole-cell currents showed that ACh-induced outward current was first detected around 5 days in a fraction of cultured OHCs. The number of responsive cells increased between 5 and 12 days in culture. The size of ACh-induced currents also increased during this period. These results suggest that the development of AChRs in cultured OHCs is not affected by removal of efferent innervation.
AB - Efferents, originating in the superior olivary complex, preferentially synapse with cochlear outer hair cells (OHCs), with acetylcholine (ACh) as their primary neurotransmitter. The OHC ACh receptors (AChRs), which have unusual pharmacology, have been cloned and identified as a new subunit (α9) of the nicotinic AChR family. The expression of α9 AChRs is first detected before birth and peaks between 6 and 10 days after birth (DAB) in developing mice and rats, while functional maturation of the receptor, as determined by measuring the ACh-induced currents, takes place between 6 and 12 DAB. In this study we attempted to examine the development of AChRs in OHCs grown in explanted cultures, deprived of efferent innervation. ACh-induced currents were used as an assay. Reverse transcription-PCR analysis was also performed to detect the expression of α9 subunit from cultured OHCs. PCR study indicates that mRNA of the α9 subunit was expressed in primary cochlear cultures, similar to that seen in the cochleae of developing animals. Measurement of whole-cell currents showed that ACh-induced outward current was first detected around 5 days in a fraction of cultured OHCs. The number of responsive cells increased between 5 and 12 days in culture. The size of ACh-induced currents also increased during this period. These results suggest that the development of AChRs in cultured OHCs is not affected by removal of efferent innervation.
UR - http://www.scopus.com/inward/record.url?scp=0035187216&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035187216&partnerID=8YFLogxK
U2 - 10.1016/S0378-5955(01)00376-8
DO - 10.1016/S0378-5955(01)00376-8
M3 - Article
C2 - 11707358
AN - SCOPUS:0035187216
VL - 162
SP - 113
EP - 125
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
IS - 1-2
ER -