Voltage-dependent sodium channels in an invertebrate striated muscle.
Striated skeletal muscles from the planktonic arrowworm Sagitta elegans (phylum Chaetognatha) were voltage-clamped. The muscles displayed classical voltage-dependent sodium channels that (i) showed peak transient currents when the membrane was depolarized 90 millivolts from rest, (ii) opened rapidly with peak currents flowing within 0.4 milliseconds at 4 degrees C, (iii) showed voltage-dependent inactivation with 50 percent inactivation at +25 millivolts from rest, and (iv) were blocked by 500 nanomolar tetrodotoxin.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000845:Annelida / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D009036:Moths; D009132:Muscles / Q000502:physiology*; D011896:Rana temporaria; D012964:Sodium / Q000378:metabolism*; D013045:Species Specificity; D013779:Tetrodotoxin / Q000633:toxicity
D007473:Ion Channels; D013779:Tetrodotoxin; D012964:Sodium