Trichloroethanol alters action potentials in a subgroup of primary sensory neurones.
We investigated the effects of 2,2,2-trichloroethanol (TCE), the active metabolite of chloral hydrate, on large-conductance calcium-activated K+ channels (BKCa channels) of dorsal root ganglion (DRG) neurones. In outside-out patches, 2 and 5 mM TCE increased the open probability of BKCa channels to 1.7-fold and 2.8-fold of control, respectively. In 50% of the cells investigated (group A) the action potential (AP) was shortened reversibly by TCE by 20% and the whole-cell outward-current was increased by 44%. Both effects could be antagonized by iberiotoxin. In a second group of neurone (group B), TCE prolonged the AP duration. The effects of TCE in group A, which was 20-fold more potent than ethanol on BKCa channels and AP might contribute to the described analgesic effect of chloral hydrate.
Gruss
Marco
M
Physiologisches Institut, Justus-Liebig-Universität, 35385 Giessen, Germany.
Hempelmann
Gunter
G
Scholz
Andreas
A
D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D002697:Chloral Hydrate / Q000494:pharmacology*; D005023:Ethylene Chlorohydrin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005260:Female; D005727:Ganglia, Spinal / Q000187:drug effects* / Q000378:metabolism; D037102:Lectins; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism; D009475:Neurons, Afferent / Q000187:drug effects* / Q000378:metabolism; D009619:Nociceptors / Q000187:drug effects / Q000378:metabolism; D009924:Organ Culture Techniques; D010146:Pain / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D010455:Peptides / Q000494:pharmacology; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D018686:Anesthetics, Intravenous; D037102:Lectins; D010455:Peptides; D024681:Potassium Channels, Calcium-Activated; D002697:Chloral Hydrate; D005023:Ethylene Chlorohydrin; C064719:iberiotoxin; C005849:2,2,2-trichloroethanol