Convergence of excitatory and inhibitory hair cell transmitters shapes vestibular afferent responses.
The vestibular semicircular canals respond to angular acceleration that is integrated to angular velocity by the biofluid mechanics of the canals and is the primary origin of afferent responses encoding velocity. Surprisingly, some afferents actually report angular acceleration. Our data indicate that hair-cell/afferent synapses introduce a mathematical derivative in these afferents that partially cancels the biomechanical integration and results in discharge rates encoding angular acceleration. We examined the role of convergent synaptic inputs from hair cells to this mathematical differentiation. A significant reduction in the order of the differentiation was observed for low-frequency stimuli after gamma-aminobutyric acid type B receptor antagonist administration. Results demonstrate that gamma-aminobutyric acid participates in shaping the temporal dynamics of afferent responses.
Holstein
Gay R
GR
Departments of Neurology and Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA. gay.holstein@mssm.edu
Rabbitt
Richard D
RD
Martinelli
Giorgio P
GP
Friedrich
Victor L
VL
Boyle
Richard D
RD
Highstein
Stephen M
SM
D000054:Acceleration; D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000818:Animals; D024541:Batrachoidiformes / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D058788:GABA-B Receptor Antagonists; D018069:Hair Cells, Vestibular / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008959:Models, Neurological; D010721:Phosphinic Acids / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D018080:Receptors, GABA-B / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D058788:GABA-B Receptor Antagonists; D010721:Phosphinic Acids; D011412:Propanolamines; D018080:Receptors, GABA-B; C085075:CGP 55845A; D005680:gamma-Aminobutyric Acid