Characterization of a transient outward current in a rapidly adapting insect mechanosensory neuron

Päivi H. Torkkeli, Andrew S. French

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

This paper describes the first voltage-clamp recordings from an arthropod cuticular sensory neuron. In the femoral tactile spine neuron of the cockroach Periplaneta americana, a rapidly activating and inactivating outward current, IA, appeared when the neuron was hyperpolarized for a short period before a depolarizing test pulse. IA could be separated from the other outward currents using 5 mM 4-aminopyridine (4-AP), which specifically blocked it. Tetraethylammonium (TEA), (50 mM) did not remove IA, but decreased the steady-state outward current by about 50%. The threshold for IA activation was about -75 mV. The minimum activation and inactivation time constants were approximately 0.2 ms and 15 ms, respectively. The voltage dependencies of activation and inactivation were well fit-ted by Boltzmann distributions, giving values of membrane potential at halfmaximal activation (V50) equal to −56.5 mV and an equivalent gating charge of n=3.9 for activation and V50=-86.7 mV and n=3.4 for inactivation. In current-clamp recordings, 4-AP reversibly reduced the cell's normal adaptation by lowering the threshold for action potentials, but did not affect the amplitude or duration of single action potentials. These results indicate that IA plays a role in short-term adaptation by opposing membrane depolarization and reducing the spike frequency during maintained stimulation.

Original languageEnglish
Pages (from-to)72-78
Number of pages7
JournalPflugers Archiv European Journal of Physiology
Volume429
Issue number1
DOIs
Publication statusPublished - Nov 1994
Externally publishedYes

ASJC Scopus Subject Areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

Fingerprint

Dive into the research topics of 'Characterization of a transient outward current in a rapidly adapting insect mechanosensory neuron'. Together they form a unique fingerprint.

Cite this

Torkkeli, P. H., & French, A. S. (1994). Characterization of a transient outward current in a rapidly adapting insect mechanosensory neuron. Pflugers Archiv European Journal of Physiology, 429(1), 72-78. https://doi.org/10.1007/BF02584032