Mytilus inhibitory peptide (MIP) induces a Na+-activated K+-current in snail neurons

T. Kiss, Y. Fujisawa, Z. Laszlo, Y. Muneoka

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Two microelectrode voltage-clamp and single-channel recordings were performed on D-cluster neurons of snail right parietal ganglion in order to study the properties of MIP-activated potassium current. It was found that the octapeptide member of the MIP-family, ASHIPRFVa elicits an outward current, which possesses all the properties characteristic for the hexapeptide(s) inward membrane response. The main component of the peptide elicited response is highly [K+](o) dependent, however the response was attenauted in Na-free extracellular saline. The peptide elicited response was mimicked by raising the [Na+](i) by pressure injection of Na+ into the cell. Single channel recordings indicated that MIP-induced outward K-current is Na-dependent. The probability to find a channel in open state increases with increasing intracellular Na+-concentration. Excised inside-out patches obtained from D-neurons contained I(K(Na)) channels could be activated by exposure of the cytoplasmic face of the patch membrane to 40 mM Na+, and 40 mM Li+, as well. The single channel current amplitude at -60 mV is 15 pA and the single channel conductance is 212 pS between -80 and 0 mV. It was concluded that MIP's activate a novel type of K+-current in the snail neurons. This current is the Na-activated K+-current. The single channel properties of the MIP activated channel is in concert with I(K(Na)) data obtained on different vertebrate and invertebrate preparations.

Original languageEnglish
Pages (from-to)133-145
Number of pages13
JournalActa biologica Hungarica
Volume51
Issue number2-4
Publication statusPublished - Sep 28 2000

Keywords

  • Cation-activated potassium channels
  • Invertebrates
  • Neuron
  • Neuropeptide
  • Snail

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Environmental Science(all)
  • Neurology

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