Effects of leucine-enkephalin on potassium currents in neurons in the rat respiratory center in vitro.
Experiments to identify the neuronal mechanisms underlying the respiratory activity of the opioid peptide leucine-enkephalin were performed on transverse slices of the rat brainstem in voltage-clamped conditions; studies addressed the effects of this peptide (10 nM-1 microM) on the potassium A current and the inward potassium current of neurons in two areas of the respiratory center: the ventrolateral area of the solitary tract nucleus and the pre-Bötzinger complex. The parameters of the A current assessed in all respiratory center neurons studied showed no change in the presence of leucine-enkephalin. At the same time, leucine-enkephalin produced reversible increases in the amplitude of the inward potassium current. These results provide evidence that the inhibitory effect of leucine-enkephalin at the level of respiratory center neurons is at least in part explained by its stimulatory action on the inward potassium current but is not associated with modulation of the potassium A current.
Inyushkin
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Samara State University, 1 Academician Pavlov Street, 443011 Samara, Russia.
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D004743:Enkephalin, Leucine / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects* / Q000528:radiation effects; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques / Q000379:methods; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012125:Respiratory Center / Q000166:cytology*; D019789:Tetraethylammonium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D000779:Anesthetics, Local; D018377:Neurotransmitter Agents; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D013779:Tetrodotoxin; D004743:Enkephalin, Leucine; D019789:Tetraethylammonium