Effects of ATP on TTX-sensitive and TTX-resistant sodium currents in rat sensory neurons.
Differential effects of ATP on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) sodium currents in rat dorsal root ganglion neurons were studied using the whole-cell variation of path-clamp technique. Currents were evoked by step depolarizations to 0 mV from a holding potential of -80 mV. ATP suppressed TTX-S sodium currents while it increased TTX-R sodium currents. The effects were concentration-dependent and were reversible upon washout with ATP-free external solution. ATP-gamma-S, a hydrolysis-resistant ATP analog, also affected two types of sodium currents similarly to ATP, excluding the possibility that the effects were caused by the products of ATP hydrolysis, namely adenosine. ATP by modulating sodium currents may exert profound effects on the transmission of sensory information such as nociception.
Song
J H
JH
Department of Pharmacology, Chung-Ang University, College of Medicine, 221 Heuk-Suk Dong, Dong-Jak Ku, Seoul 156-756, South Korea.
Shin
Y K
YK
Lee
C S
CS
Bang
H
H
Park
M
M
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D000345:Affinity Labels / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D010146:Pain / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D018408:Patch-Clamp Techniques; D051381:Rats; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology*
D000345:Affinity Labels; D018047:Receptors, Purinergic P1; D018048:Receptors, Purinergic P2; D015222:Sodium Channels; C022571:adenosine 5'-O-(3-thiotriphosphate); D013779:Tetrodotoxin; D000255:Adenosine Triphosphate