[Voltage-gated influx ion channels expressed in Xenopus oocytes after the administration of brain mRNA].
Expression of "fast", TTX-sensitive sodium and high-threshold calcium channels in the membrane of Xenopus oocytes following mRNA injection from the rat brain has been detected using two microelectrode voltage clamp technique. Barium current through expressed calcium channels was blocked by 200 mumol/l Cd2+ and was insensitive to D-600 (20 mumol/l) and nitrendipine (50 mumol/l). Expressed barium current was inhibited within 20-40 min by omega-conotoxin, a peptide neurotoxin known to block high-threshold calcium channels of the neuronal membrane, in 1 mumol/l concentration. A steady-state inactivation curve for this current could be fitted by the Boltzmann relation with V1/2 = -50 mV and k = 14 mV. Voltage-dependent and pharmacological properties of calcium channels which appeared in the oocyte membrane following mRNA injection from the mammalian brain resembled most of all those of high-threshold inactivating (HTI- or N-type) calcium channels of neurons in spite they did not demonstrate prominent time-dependent inactivation. Evidences in favour of expressed calcium channels heterogeneity were not obtained.
Gerasimenko
O V
OV
Kostiuk
P G
PG
Liubanova
O P
OP
Fedulova
S A
SA
Shuba
Ia M
IaM
D000818:Animals; D001464:Barium / Q000378:metabolism; D001921:Brain / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D015640:Ion Channel Gating / Q000187:drug effects* / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008978:Mollusk Venoms / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010456:Peptides, Cyclic / Q000494:pharmacology; D011061:Poly A / Q000302:isolation & purification / Q000494:pharmacology*; D012333:RNA, Messenger / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014982:Xenopus laevis / Q000502:physiology*; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D007473:Ion Channels; D008978:Mollusk Venoms; D010456:Peptides, Cyclic; D012333:RNA, Messenger; D015222:Sodium Channels; D013757:Tetraethylammonium Compounds; D020960:omega-Conotoxins; C053423:Conus magus toxin; D011061:Poly A; D001464:Barium; D013779:Tetrodotoxin
Potentsialupravliaemye ionnye kanaly vkhodiashchego toka, ékspressirovannye v ootsitakh Xenopus posle vvedeniia mozgovoĭ mRNK.