ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Comparative measurements have been made of the transepidermal voltage recorded between the haemolymph space and the outer surface of the cuticle (a) at the site of sensilla and (b) at epidermal sites free of sensilla for representatives of various orders of insects and for terrestrial species of Crustacea and Arachnidae. 1. The transepidermal voltage at the site of sensilla has been found between 20 and 80 mV, with the cuticular side being positive, in contrast to about 0 mV at epidermal regions free of sensilla (Donnan-type voltages within the cuticle excluded by sufficiently high electrolyte concentrations). a. The locally increased voltage is present at sensilla of all groups of hemi- and holometabolous insects and also of a representative of Crustacea (wood-louseArmadillidium) tested, however, not of spiders. b. The locally increased voltage is present at all insect sensilla for all modalities of adequate stimuli tested (Table 1). 2. Anoxia or cyanide reduce the local voltage at sensilla to the voltage found remote from sensilla. During anoxia the main voltage component at insect sensilla decays within 1 or a few minutes; it is re-established within some 10s following resupply of O2 after some minutes of anoxia. A smaller component at insect sensilla and the total voltage at isopod sensilla decays only irreversibly within 1/2 to 1 h of anoxia. 3. The amplitude of the acutely O2-dependent voltage is strongly reduced during a few days before ecdysis (molting). On the basis of the subsequent paper (Küppers and Thurm, 1979) the acutely O2-dependent voltage at insect sensilla is interpreted as reflecting local electrogenic ion transport activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00610470
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