ATP evokes different currents in TTX-sensitive and TTX-resistant cells of dorsal root ganglia.
The relationship between the level of expression of tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) sodium currents and the occurrence of two kinetically different ATP-induced currents in rat dorsal root ganglion neurons was studied. ATP evoked two distinct types of currents, one with fast activation and desensitization (I-fast) and the other with slow and persistent development (I-slow). In all TTX-S cells which expressed solely TTX-S sodium currents ATP evoked I-fast. The other cells expressed a variable proportion of TTX-S and TTX-R sodium currents. Only 15% of these TTX-R+S cells responded to ATP with I-fast. I-slow was evoked in both cell types but the magnitude of response was much greater in TTX-R+S cells. This result suggests that a different array of ion channels is equipped in different types of sensory neurons.
Song
J H
JH
Department of Pharmacology, Chung-Ang University, College of Medicine, Seoul, South Korea.
Shin
Y K
YK
Lee
C S
CS
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D004351:Drug Resistance; D004553:Electric Conductivity; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology*; D013997:Time Factors
D015222:Sodium Channels; D013779:Tetrodotoxin; D000255:Adenosine Triphosphate