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. 1979 Jun;291:327–337. doi: 10.1113/jphysiol.1979.sp012816

Intracellular citrate or externally applied tetraethylammonium ions produce calcium-dependent action potentials in an insect motoneurone cell body

Robert M Pitman 1
PMCID: PMC1280904  PMID: 480220

Abstract

1. Electrophysiological observations have been made upon the cell body of an identified motoneurone of the cockroach, Periplaneta americana. Normal responses were compared with those observed after intracellular injection of citrate anions or when the preparation was bathed in solutions containing tetraethylammonium ions (TEA+).

2. Normally when depolarized, the motoneurone soma gave a series of damped oscillations; the amplitude of these responses increased with increase in the applied current.

3. After citrate ions had been injected into the neurone soma, all-or-none action potentials were evoked by depolarization; such responses appeared about 5-10 min after the onset of citrate injection. Injection of EGTA produced similar effects. Citrate and EGTA probably produce their effect through a reduction in the intracellular free calcium concentration.

4. When preparations were bathed in saline solution containing 50 mM-TEA+, soma depolarization produced prolonged all-or-none action potentials (up to approximately 100 msec duration).

5. The action potentials produced by citrate injection or externally applied TEA+ appeared to have a similar ionic mechanism; they were not depressed by sodium-free solutions or by tetrodotoxin (4 × 10-6 M) but were reversibly blocked in saline solution containing 40 mM-manganous chloride.

6. The overshoot amplitude of action potentials recorded after injection of citrate anions or in solutions containing TEA+ showed a 22·5 mV change for a ten-fold change in the external calcium concentration.

7. Both intracellular citrate and external TEA+ caused a significant increase in the input resistance and membrane time constant of the motoneurone.

8. It is concluded that action potentials generated under various experimental conditions in the soma of this insect motoneurone map have differing ionic mechanisms.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. FATT P., GINSBORG B. L. The ionic requirements for the production of action potentials in crustacean muscle fibres. J Physiol. 1958 Aug 6;142(3):516–543. doi: 10.1113/jphysiol.1958.sp006034. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. FATT P., KATZ B. Conduction of impulses in crustacean muscle fibres. J Physiol. 1951 Sep;115(1):45–P. [PubMed] [Google Scholar]
  3. FATT P., KATZ B. The electrical properties of crustacean muscle fibres. J Physiol. 1953 Apr 28;120(1-2):171–204. doi: 10.1113/jphysiol.1953.sp004884. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. FRANKENHAEUSER B., HODGKIN A. L. The action of calcium on the electrical properties of squid axons. J Physiol. 1957 Jul 11;137(2):218–244. doi: 10.1113/jphysiol.1957.sp005808. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Godfraind J. M., Kawamura H., Krnjević K., Pumain R. Actions of dinitrophenol and some other metabolic inhibitors on cortical neurones. J Physiol. 1971 May;215(1):199–222. doi: 10.1113/jphysiol.1971.sp009465. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Godfraind J. M., Krnjević K., Pumain R. Unexpected features of the action of dinitrophenol on cortical neurones. Nature. 1970 Nov 7;228(5271):562–564. doi: 10.1038/228562a0. [DOI] [PubMed] [Google Scholar]
  7. Gorman A. L., McReynolds J. S. Control of membrane N+ permeability in a hyperpolarizing photoreceptor: similar effect of light and metabolic inhibitors. Science. 1974 Aug 16;185(4151):620–621. doi: 10.1126/science.185.4151.620. [DOI] [PubMed] [Google Scholar]
  8. HAGIWARA S., NAKA K. I., CHICHIBU S. MEMBRANE PROPERTIES OF BARNACLE MUSCLE FIBER. Science. 1964 Mar 27;143(3613):1446–1448. doi: 10.1126/science.143.3613.1446. [DOI] [PubMed] [Google Scholar]
  9. HAGIWARA S., NAKA K. I. THE INITIATION OF SPIKE POTENTIAL IN BARNACLE MUSCLE FIBERS UNDER LOW INTRACELLULAR CA++. J Gen Physiol. 1964 Sep;48:141–162. doi: 10.1085/jgp.48.1.141. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hagiwara S., Nakajima S. Differences in Na and Ca spikes as examined by application of tetrodotoxin, procaine, and manganese ions. J Gen Physiol. 1966 Mar;49(4):793–806. doi: 10.1085/jgp.49.4.793. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hoyle G., Burrows M. Neural mechanisms underlying behavior in the locust Schistocerca gregaria. II. Integrative activity in metathoracic neurons. J Neurobiol. 1973;4(1):43–67. doi: 10.1002/neu.480040105. [DOI] [PubMed] [Google Scholar]
  12. Isnberg G. Is potassium conductance of cardiac Purkinje fibres controlled by (Ca2+)? Nature. 1975 Jan 24;253(5489):273–274. doi: 10.1038/253273a0. [DOI] [PubMed] [Google Scholar]
  13. Kleinhaus A. L., Prichard J. W. Calcium dependent action potentials produced in leech Retzius cells by tetraethylammonium chloride. J Physiol. 1975 Mar;246(2):351–369. doi: 10.1113/jphysiol.1975.sp010894. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Krnjevíc K., Puil E., Werman R. Evidence for Ca2+-activated K+ conductance in cat spinal motoneurons from intracellular EGTA injections. Can J Physiol Pharmacol. 1975 Dec;53(6):1214–1218. doi: 10.1139/y75-171. [DOI] [PubMed] [Google Scholar]
  15. Meech R. W., Standen N. B. Potassium activation in Helix aspersa neurones under voltage clamp: a component mediated by calcium influx. J Physiol. 1975 Jul;249(2):211–239. doi: 10.1113/jphysiol.1975.sp011012. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Meech R. W. The sensitivity of Helix aspersa neurones to injected calcium ions. J Physiol. 1974 Mar;237(2):259–277. doi: 10.1113/jphysiol.1974.sp010481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Naitoh Y., Eckert R., Friedman K. A regenerative calcium response in Paramecium. J Exp Biol. 1972 Jun;56(3):667–681. doi: 10.1242/jeb.56.3.667. [DOI] [PubMed] [Google Scholar]
  18. Pearson K. G., Iles J. F. Discharge patterns of coxal levator and depressor motoneurones of the cockroach, Periplaneta americana. J Exp Biol. 1970 Feb;52(1):139–165. doi: 10.1242/jeb.52.1.139. [DOI] [PubMed] [Google Scholar]
  19. Pitman R. M., Tweedle C. D., Cohen M. J. Electrical responses of insect central neurons: augmentation by nerve section or colchicine. Science. 1972 Nov 3;178(4060):507–509. doi: 10.1126/science.178.4060.507. [DOI] [PubMed] [Google Scholar]

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