Neurohormone D increases the intracellular Ca2+ level in cockroach neurones through a Cd(2+)-sensitive Ca2+ influx.
The modulating effect of the octapeptide neurohormone D (NHD) on the intracellular calcium level [Ca2+]i of neurones from the dorsal midline of the cockroach terminal ganglion was investigated with fluorescence measurements. [Ca2+]i of cells loaded with Fura 2 was determined by photon counting and imaging at wavelengths of 340 and 380 nm. After application of NHD, [Ca2+]i increased within 3 min from a value of 93 +/- 36 nM to 153 +/- 51 nM, corresponding to an enhancement to 164 +/- 35%. In Ca(2+)-free solution, [Ca2+]i was lowered (52 +/- 6 nM) and NHD no longer affected the intracellular calcium level. The presence of 0.1 mM Cd2+, in normal saline, prevented the NHD-induced increase of [Ca2+]i. The results were explained by postulating a Ca2+ resting current in these cells which is augmented by NHD.
Wicher
D
D
Sächsische Akademie der Wissenschaften zu Leipzig, Jena, FRG.
Reuter
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G
D000818:Animals; D002104:Cadmium / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D016257:Fura-2; D066298:In Vitro Techniques; D007301:Insect Hormones / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000494:pharmacology*; D010526:Periplaneta / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D015220:Calcium Channels; D007301:Insect Hormones; D009479:Neuropeptides; D002104:Cadmium; C043192:glutamyl-valyl-asparaginyl-phenylalanyl-seryl-prolyl-asparaginyl-tryptophanamide; D002118:Calcium; D016257:Fura-2