Inhibition of PaCaMKII-E isoform in the dorsal unpaired median neurosecretory cells of cockroach reduces nicotine- and clothianidin-induced currents.
Cellular responses to Ca(2+) require intermediary proteins such as calcium/calmodulin-dependent protein kinase II (CaMKII), which transduces the signal into downstream effects. We recently demonstrated that the cockroach genome encodes five different CaMKII isoforms, and only PaCaMKII-E isoform is specifically expressed in the dorsal unpaired median neurosecretory cells. In the present study, using antisense oligonucleotides, we demonstrated that PaCaMKII-E isoform inhibition reduced nicotine-induced currents through α-bungarotoxin-sensitive and -insensitive nicotinic acetylcholine receptor subtypes. Specifically, PaCaMKII-E isoform is sufficient to repress nicotinic current amplitudes as a result of its depression by antisense oligonucleotides. Similar results were found using the neonicotinoid insecticide clothianidin, which acted as a full agonist of dorsal unpaired median neuron nicotinic acetylcholine receptors. Clothianidin current amplitudes are strongly reduced under bath application of PaCaMKII-E antisense oligonucleotides but no significant results are found with α-bungarotoxin co-applied, demonstrating that CaMKII-E isoform affects nicotine currents through α-bungarotoxin-sensitive and -insensitive receptor subtypes whereas clothianidin currents are reduced via α-bungarotoxin-insensitive receptors. In addition, we found that intracellular calcium increase induced by nicotine and clothianidin were reduced by PaCaMKII-E antisense oligonucleotides, demonstrating that intracellular calcium increase induced by nicotine and clothianidin are affected by PaCaMKII-E inhibition. Cellular responses to Ca(2+) require intermediary proteins such as calcium/calmodulin-dependent protein kinase II (CaMKII). We recently demonstrated that the cockroach genome encodes five different CaMKII isoforms and only PaCaMKII-E isoform was specifically expressed in the dorsal unpaired median neurosecretory cells. Here we show that specific inhibition of PaCaMKII-E isoform is associated with a decrease in nicotine- and clothianidin-induced currents. In addition, analysis of calcium changes demonstrates that PaCaMKII-E inhibition induces a decrease in intracellular calcium concentration.
Laboratoire Récepteurs et Canaux Ioniques Membranaires (RCIM), UPRES EA 2647/USC INRA 1330/SFR 4207 QUASAV, Université d'Angers, UFR Sciences, Angers, France.
Olivier
O
List
Delphine
D
Calas-List
Emiliane
E
Taillebois
Marjorie
M
Juchaux
Emilie
E
Heuland
Steeve H
SH
Thany
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D020013:Calcium Signaling / Q000187:drug effects; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors*; D003058:Cockroaches / Q000502:physiology*; D055724:Electrophysiological Phenomena; D017952:Ganglia, Invertebrate / Q000187:drug effects / Q000378:metabolism; D006146:Guanidines / Q000494:pharmacology*; D007150:Immunohistochemistry; D008297:Male; D000073943:Neonicotinoids; D009490:Neurosecretory Systems / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D060888:Real-Time Polymerase Chain Reaction; D011978:Receptors, Nicotinic / Q000187:drug effects; D013844:Thiazoles / Q000494:pharmacology*
D015220:Calcium Channels; D006146:Guanidines; D000073943:Neonicotinoids; D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; D013844:Thiazoles; C480342:clothianidin; D009538:Nicotine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2
CaMKII; calcium; clothianidin; nicotine; nicotinic receptors