The effect of MII α-conotoxin and its N-terminal derivatives on Ca- and Na-signals induced by nicotine in SH-SY5Y neuroblastoma cells.
- Resource Type
- Article
- Authors
- Surin, A.; Kryukova, E.; Strukov, A.; Zhmak, M.; Talka, R.; Tuominen, R.; Salminen, O.; Khiroug, L.; Kasheverov, I.; Tsetlin, V.
- Source
- Russian Journal of Bioorganic Chemistry. Mar2012, Vol. 38 Issue 2, p184-191. 8p.
- Subject
- *CONOTOXINS
*NICOTINIC receptors
*INTRACELLULAR calcium
*NEUROBLASTOMA
*NICOTINE
- Language
- ISSN
- 1068-1620
Nicotinic acetylcholine receptors (nAChRs) are involved in the regulation of intracellular Ca-dependent processes both in normal and pathological states. α-Conotoxins from the venom of Conus marine mollusks are a valuable tool for the investigation of the pharmacological action and functional role of nAChRs. Analogues of α-conotoxin MII labeled by Bolton-Hunter reagent (BH-MII) or fluorescein isothiocyanate (FITC-MII) on the N-terminal glycine residue have been synthesized in the present work. Fluorescence microscopy studies of SH-SY5Y neuroblastoma cells loaded with Ca indicator Fura-2, or by both Ca indicator Fluo-4 and Na indicator SBFI, were used to test the effect of MII modification on its ability to block Ca and Na signals induced by nicotine. Measurements in SH-SY5Y cells showed that kinetics of the increase and recovery of the concentration of free Ca ([Ca]) upon nicotine application and washout was different from that for free Na ([Na]), this being evidence of differences in the mechanism of Ca and Na homeostasis regulation. MII suppressed the nicotine-induced increase of [Ca] and [Na] in a concentration-dependent manner. An additional tyrosine residue added to the N-terminus of one of the MII derivatives caused a significant decrease in the inhibitory action of MII; this decrease was even more pronounced when a large FITC label was introduced into MII. The BH-MII derivative had an inhibitory effect similar to that of unmodified α-conotoxin. MII and its iodinated derivatives are promising tools for radioligand assays. [ABSTRACT FROM AUTHOR]