title: [The effect of sodium, potassium and calcium ions on the functional characteristics of catfish electroreceptors].
abstract: Afferent responses of single afferent fibre from small pit organs to various concentration of potassium, sodium and calcium ions were studied in the catfish (Ictalurus nebulosus). The receptors were stimulated with d. c. pulses. Calcium concentration between 0.4-5 mM/1 were practically ineffective. Calcium concentration from 5 to 100 7m/1 increased the threshold to electrical stimulation. 2mM/1 sodium and potassium solutions caused an increase in the threshold to the anodic stimuli and elimination of the responses to the cathodic ones. This effect disappeared after the addition of 0.4 mM/1 CaCl2 or application of long anodic stimuli of great intensity (10(-8)-10(-7) A/mm2). With an increase in potassium concentration to 10-20 mM/1 the threshold returned to the initial level. Potassium concentrations above 20 mM/1 increased the threshold to electrical stimuli. The effect of ions was compared with the action of electric current.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004560:Electricity; D004594:Electrophysiology; D005399:Fishes; D011188:Potassium / Q000494:pharmacology*; D011984:Sensory Receptor Cells / Q000187:drug effects*; D012964:Sodium / Q000494:pharmacology*
chemical_list: D012964:Sodium; D011188:Potassium; D002118:Calcium
vernacular_title: Vliianie ionov natriia, kaliia i kal'tsiia na funktsional'nye kharakteristiki élektroretseptorov karlikovykh somikov