Voltage-gated ionic currents and their roles in timing coding in auditory neurons of the nucleus magnocellularis of the chick

Content Provider	Semantic Scholar
Author	Koyano, Konomi Funabiki, Kazuo Ohmori, Harunori
Copyright Year	1996
Abstract	Avian cochlear neurons of the nucleus magnocellularis (NMC) are known to encode temporal information of sound. The neuron generated only a single action potential at a stable timing even though suprathreshold currents of long duration (> 100 ms) was injected. The threshold for the action potential was -42 mV. In voltage-clamp experiments, a TTX-sensitive Na current was activated at membrane potentials more positive than -50 mV. A low voltage activated (LVA) Ca current and a high voltage activated (HVA) Ca current were observed. The LVA Ca current was activated from -65 mV and showed a voltage dependent inactivation. The HVA Ca current was activated from -40 mV and did not show any inactivation. The LVA Ca current and the HVA Ca current were sensitive to Ni2+ (0.1 mM) and Nifedipine (10-20 mM), respectively. NMC neurons showed a TEA-sensitive K current and a 4-AP-sensitive K current. With 4-AP (0.5 mM) in a bathing medium, the threshold of action potential was decreased to -49 mV and the timing of action potential generation showed a wider distribution than that of control. Ni2+ (0.1 mM) reversed effects of 4-AP on the threshold and the variability of action potential onsets. It is concluded that a 4-AP-sensitive current counteracts the LVA Ca current that facilitates Na spike generation, and sets a threshold to a higher level for generating a single action potential at a precise timing following synaptic inputs from the auditory nerve.
Starting Page	29
Ending Page	45
Page Count	17
File Format	PDF HTM / HTML
DOI	10.1016/0168-0102(96)01071-1
PubMed reference number	8895890
Journal	Medline
Volume Number	26
Alternate Webpage(s)	https://api.elsevier.com/content/article/pii/0168010296010711
Alternate Webpage(s)	https://www.sciencedirect.com/science/article/pii/0168010296010711?dgcid=api_sd_search-api-endpoint
Alternate Webpage(s)	https://doi.org/10.1016/0168-0102%2896%2901071-1
Journal	Neuroscience Research
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article