High blood potassium in insects in relation to nerve conduction.

Abstract

THE analyses of Bishop1, Bone2, Brecher3, Drilhon4, Tobias5, and others show that in phytophagous insects the potassium concentration in the haemolymph is always high and exceeds 70 mM/litre in some instances. Such values would depolarize vertebrate or crustacean nerve fibres and stop conduction6. Insect nerves may have different properties in regard to potassium, or this may be bound in some way to the organic constituents of the blood. Alternatively7, the fibres may be protected from the high blood potassium by a sheath capable of ionic regulation, providing the axons with a local environment containing a lower potassium concentration than that of the blood.