Ionic Composition of Haemolymph and Nervous Function in the Cockroach, Periplaneta Americana L
Open Access
- 1 August 1968
- journal article
- Published by The Company of Biologists in Journal of Experimental Biology
- Vol. 49 (1), 31-38
- https://doi.org/10.1242/jeb.49.1.31
Abstract
1. Resting and action potentials have been recorded in giant axons of the cockroach when the intact nerve cord was bathed in the insect's own haemolymph. 2. Low resting potentials (43.0±4.8 mV.) and large action potentials (105.1±6.8 mV.) were obtained in these preparations as compared with those recorded in de-sheathed nerve cords. 3. Recordings of the maximum rates of rise and fall have shown that the shape of the action potential was essentially similar in de-sheathed preparations and in intact nerve cords. 4. These results have been discussed in terms of the unequal distribution of ions between the haemolymph, the extracellular fluid and the axoplasm of the giant axons. 5. The low measured resting potential agrees with a K+ concentration in the haemolymph of about 20 mM./l., a value which is only slightly lower than the measured one (Pichon, 1963). 6.The occurrence of large action potentials in these apparently depolarized axons may be related to the stabilizing action of divalent cations such as Ca2+ which are contained in the extracellular fluid in relatively large amounts. 7. The very large recorded overshoots (62.1±7.0 mV.) may be linked with a low sodium concentration in the axoplasm and a high sodium concentration in the extracellular fluid of the giant axons of intact nerve cords, thus resulting in a high sodium equilibrium potential, ENa.This publication has 16 references indexed in Scilit:
- Haemocytes and the Measurement of Potassium in Insect BloodNature, 1967
- Dependence of excitability of cockroach giant axons on external divalent cationsComparative Biochemistry and Physiology, 1966
- Modifications of the ionic content of the haemolymph and of the activity of Periplaneta americana in relation to dietJournal of Insect Physiology, 1963
- Distribution of Water and Inorganic Ions in the Central Nervous System of an Insect (Periplaneta Americana L.)Nature, 1962
- The effects of potassium and sodium ions on the resting and action potentials of the cockroach giant axonJournal of Insect Physiology, 1959
- PROPERTIES OF THE CONNECTIVE TISSUE SHEATH OF THE COCKROACH ABDOMINAL NERVE CORD ,The Biological Bulletin, 1956
- The Chemical Composition of the Haemolymph in Periplaneta AmericanaArchives Néerlandaises de Zoologie, 1956
- The sodium and potassium content of cephalopod nerve fibresThe Journal of Physiology, 1951
- The effect of potassium and calcium on the nervous system of the cockroach, periplaneta americanaJournal of Cellular and Comparative Physiology, 1948
- The high potassium and low sodium in the body fluid and tissues of a phytophagous insect, the silkworm Bombyx mori and the change before pupationJournal of Cellular and Comparative Physiology, 1948