Nicotinic acetylcholine receptors regulate vestibular afferent gain and activation timing

作者：Morley Barbara J^*; Lysakowski Anna; Vijayakumar Sarath; Menapace Deanna; Jones Timothy A

来源：Journal of Comparative Neurology, 2017, 525(5): 1216-1233.

DOI：10.1002/cne.24131

• utricle
• saccule
• macula
• latency
• amplitude
• evoked potential
• efferent
• RRID:AB_2079751
• RRID:AB_ 90764
• RRID:AB_2616561
• RRID:SCK_002865
• RRID:IMSR_JAX:000664
• RRID:SCR_00207

Little is known about the function of the cholinergic efferents innervating peripheral vestibular hair cells. We measured vestibular sensory evoked potentials (VsEPs) in 9 knockout (KO) mice, 10 KO mice, 7 KO mice, 9/10 and 7/9 double KO mice, and wild-type (WT) controls. We also studied the morphology and ultrastructure of efferent terminals on vestibular hair cells in 9, 10, and 9/10 KOs. Both type I and type ll vestibular hair cells express the 9 and 10 subunits. The efferent boutons on vestibular cells in 9, 10, and 9/10 KOs appeared normal, but a quantitative analysis was not performed. Mean VsEP thresholds were significantly elevated in 9 and 9/10 KO animals. Some 9 and 9/10 KO animals, however, had normal or near-normal thresholds, whereas others were greatly affected. Despite individual variability in threshold responses, latencies were consistently shortened. The double 7/9 KO resulted in decreased variance by normalizing waveforms and latencies. The phenotypes of the 7 and 10 single KOs were identical. Both 7 and 10 KO mice evidenced normal thresholds, decreased activation latencies, and larger amplitudes compared with WT mice. The data suggest a complex interaction of nicotinic acetylcholine receptors (nAChRs) in regulating vestibular afferent gain and activation timing. Although the 9/10 heteromeric nAChR is an important component of vestibular efferent activity, other peripheral or central nAChRs involving the 7 subunit or 10 subunit and 9 homomeric receptors are also important. J. Comp. Neurol. 525:1216-1233, 2017.

• 出版日期2017-4-1