Difference in calcium sensitivities of the sodium transporting systems in the nervous system of susceptible and kdr-resistant houseflies, Musca domestica L.
1. The synaptosomal preparations from the kdr-resistant strains have lower responsiveness to externally applied Ca2+ than the susceptible counterparts with respect to their Na+/Ca2+ exchange, Na+ uptake, Na+-Ca2+ protein kinase-phosphatase and its phosphorylation activities. 2. In vivo toxicity tests support the above in vitro observation in that the kdr-resistant strain shows a significant cross-resistance to agents known to affect the Na+ channel operations, those which increase intracellular Ca2+ or act as effective Ca2+ substitutes. 3. Such evidence indicates a possibility of a causal relationship between kdr resistance and the reduction of Ca2+ sensitivity by these ATP-utilizing systems including the Na+ transporting systems in the resistant insects.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D003634:DDT / Q000494:pharmacology; D004351:Drug Resistance; D006793:Houseflies / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D009420:Nervous System / Q000378:metabolism; D009498:Neurotoxins / Q000494:pharmacology; D010882:Piperonyl Butoxide / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013045:Species Specificity
D007306:Insecticides; D009498:Neurotoxins; D012964:Sodium; D003634:DDT; D000252:Calcium-Transporting ATPases; D010882:Piperonyl Butoxide; D002118:Calcium