Calcium influx in active Aplysia neurones detected by injected aequorin.

ACTION potentials may be recorded in Aplysia1,2 and Helix3 neurones in sodium and in calcium-free solutions, provided that either ion is present in the medium. The inward current may be due to both, calcium and sodium ions. To test this directly, the calcium activated photoprotein aequorin4–7 was used as it has been for the barnacle muscle fibre8,9, the squid giant axon10 and recently for the squid giant synapse11.

[1]  J. W. Hastings,et al.  Response of Aequorin Bioluminescence to Rapid Changes in Calcium Concentration , 1969, Nature.

[2]  C. Nicholson,et al.  Calcium Transient in Presynaptic Terminal of Auid Giant Synapse: Detection with Aequorin , 1972, Science.

[3]  O. Shimomura,et al.  FURTHER DATA ON THE BIOLUMINESCENT PROTEIN, AEQUORIN. , 1963, Journal of cellular and comparative physiology.

[4]  D. Junge.  Multi-ionic Action Potentials in Molluscan Giant Neurones , 1967, Nature.

[5]  E. Kandel,et al.  MORPHOLOGICAL AND FUNCTIONAL PROPERTIES OF IDENTIFIED NEURONS IN THE ABDOMINAL GANGLION OF APLYSIA CALIFORNICA , 1967 .

[6]  O. Shimomura,et al.  Preparation and use of aequorin for rapid microdetermination of Ca 2+ in biological systems. , 1972, Nature: New biology.

[7]  O. Shimomura,et al.  Microdetermination of Calcium by Aequorin Luminescence , 1963, Science.

[8]  R. Miledi.  Lanthanum Ions abolish the “Calcium Response” of Nerve Terminals , 1971, Nature.

[9]  Baker Pf,et al.  Depolarization and calcium entry in squid giant axons. , 1971 .

[10]  E. B. Ridgway,et al.  Simultaneous Recording of Membrane Potential, Calcium Transient and Tension in Single Muscle Fibres , 1968, Nature.

[11]  B. Katz,et al.  Input–Output Relation of a Single Synapse , 1966, Nature.

[12]  C. Armstrong,et al.  Anomalous Rectification in the Squid Giant Axon Injected with Tetraethylammonium Chloride , 1965, The Journal of general physiology.

[13]  D. Junge,et al.  Sodium and calcium components of action potentials in Aplysia giant neurone , 1968, The Journal of physiology.

[14]  E. B. Ridgway,et al.  Calcium transients in single muscle fibers. , 1967, Biochemical and biophysical research communications.

[15]  O. Shimomura,et al.  Extraction, purification and properties of aequorin, a bioluminescent protein from the luminous hydromedusan, Aequorea. , 1962, Journal of cellular and comparative physiology.