Mechanosensitivity of voltage-gated K+ currents in rat trigeminal ganglion neurons.
We investigated the mechanosensitivity of voltage-gated K+ channel (VGPC) currents by using whole-cell patch clamp recording in rat trigeminal ganglion (TG) neurons. On the basis of biophysical and pharmacological properties, two types of VGPC currents were isolated. One was transient (I(K,A)), the other sustained (I(K,V)). Hypotonic stimulation (200 mOsm) markedly increased both I(K,A) and I(K,V) without affecting their activation and inactivation kinetics. Gadolinium, a well-known blocker of mechanosensitive channels, failed to block the enhancement of I(K,A) and I(K,V) induced by hypotonic stimulation. During hypotonic stimulation, cytochalasin D, an actin-based cytoskeletal disruptor, further increased I(K,A) and I(K,V), whereas phalloidin, an actin-based cytoskeletal stabilizer, reduced I(K,A) and I(K,V). Confocal imaging with Texas red-phalloidin showed that actin-based cytoskeleton was disrupted by hypotonic stimulation, which was similar to the effect of cytochalasin D. Our results suggest that both I(K,A) and I(K,V) are mechanosensitive and that actin-based cytoskeleton is likely to regulate the mechanosensitivity of VGPC currents in TG neurons.
Department of Physiology and Molecular and Cellular Neuroscience Program, College of Dentistry and Dental Research Institute, Seoul National University, Chongno-Ku, Seoul, Korea.
Lin
L
Piao
Haeyeong
H
Lee
Hai Ying
HY
Li
Chul-Kyu
CK
Park
Ik-Hyun
IH
Cho
Zheng Gen
ZG
Piao
Sung Jun
SJ
Jung
Se-Young
SY
Choi
Sung Joong
SJ
Lee
Kyungpyo
K
Park
Joong-Soo
JS
Kim
Seog Bae
SB
Oh
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D007038:Hypotonic Solutions / Q000494:pharmacology; D008465:Mechanoreceptors / Q000378:metabolism*; D040542:Mechanotransduction, Cellular / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018613:Microscopy, Confocal; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010590:Phalloidine / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012668:Trigeminal Ganglion / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014966:Xanthenes
D007038:Hypotonic Solutions; D019384:Nucleic Acid Synthesis Inhibitors; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D014966:Xanthenes; D010590:Phalloidine; D015638:Cytochalasin D; C034657:Texas red