Effects of lysophosphatidic acid on sodium currents in rat dorsal root ganglion neurons.
Lysophosphatidic acid (LPA), a simple phospholipid, induces pain. To elucidate an involvement of ion channel mechanism in the LPA-induced pain, its effects on sodium currents in rat dorsal root ganglion (DRG) neurons were investigated. LPA suppressed tetrodotoxin-sensitive (TTX-S) sodium current, but increased tetrodotoxin-resistant (TTX-R) sodium current, when currents were evoked by step depolarizations to 0 mV from a holding potential of -80 mV. In both types of currents, LPA produced a hyperpolarizing shift of both activation and inactivation voltages. LPA had a negligible effect on the maximal conductance of TTX-S current, but increased that of TTX-R current. The results suggest that the enhancement of TTX-R current may contribute to the LPA-induced pain.
Seung Lee
Woo
W
Department of Pharmacology, Chung-Ang University, College of Medicine, 221 Heuksuk-Dong, Dongjak-Ku, Seoul 156-756, Republic of Korea.
Hong
Min-Pyo
MP
Hoon Kim
Tae
T
Kyoo Shin
Yong
Y
Soo Lee
Chung
C
Park
Mijung
M
Song
Jin-Ho
JH
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004347:Drug Interactions; D005727:Ganglia, Spinal / Q000166:cytology*; D008246:Lysophospholipids / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009474:Neurons / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D008246:Lysophospholipids; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin; C032881:lysophosphatidic acid