[Effect of alpha-conotoxin MII and its N-terminal derivatives on Ca2+ and Na+ signals induced by nicotine in neuroblastoma cell line SH-SY5Y].

Abstract

Nicotinic acetylcholine receptors (nAChRs) are implicated in the regulation ofintracellular Ca2+-dependent processes in cells both in normal and pathological states, alpha-Conotoxins isolated from Conus snails venom are a valuable tool for the study of pharmacological properties and functional role of nAChRs. In the present study the alpha-conotoxin MII analogue with the additional tyrosine attached to the N terminus (Y0-MII) was prepared. Also we synthesized analogs with the N-terminal glycine residue labeled with the Bolton- Hunter reagent (BH-MII) or fluorestsein isothiocyanate (FITC-MII). Fluorescence microscopy studies of the neuroblastoma SH-SY5Y cells loaded with Ca2+ indicator Fura-2 or with Ca2+ and Na+ indicators Fluo-4 and SBFI were performed to examine effect of MII modification on its ability to inhibit nicotin-induced increases in intracellular free Ca2+ and Na+ concentrations ([Ca2+] and [Na+]i respectively). Monitoring of individual cell [Ca2+]i and [Na+]i signals revealed different kinetics of [Ca2+]i and [Na+]i rise and decay in responses to brief nicotine (Nic) applications (10-30 microM, 3-5 min), which indicates to different mechanisms of Ca2+ and Na+ homeostasis control in SH-SY5Y cells. MII inhibited in concentration-dependent manner the both [Ca2+]i and [Na+]i increase induced by Nic. Additional tyrosine in the Y0-MII or, especially, more sizeable label in FITC-MII significantly reduced the inhibitory effect of MII. Whereas the efficiency of the Ca2+ response inhibition by BH-MII was found to be close to the efficiency of its inhibition by natural alpha-conotoxin MII, radioiodinated derivatives BH-MII can be used in radioligand assay.

• Authors: A M Surin, E V Kriukova, A S Strukov, M N Zhmak, R Talka, R Tuominen, O Salminen, L Khiroug, I E Kasheverov, V I Tsetlin
• Journal: Bioorganicheskaia khimiia (Bioorg Khim) 2012 Mar-Apr Vol. 38 Issue 2 Pg. 214-22 ISSN: 0132-3423 [Print] Russia (Federation)
• PMID: 22792725 (Publication Type: English Abstract, Journal Article)

Chemical References

• Conotoxins
• Neoplasm Proteins
• Nicotinic Agonists
• Receptors, Nicotinic
• Nicotine
• Sodium
• Calcium

Topics

• Calcium (metabolism)
• Calcium Signaling (drug effects)
• Cell Line, Tumor
• Conotoxins (pharmacology)
• Humans
• Neoplasm Proteins (agonists, metabolism)
• Neuroblastoma (metabolism, pathology)
• Nicotine (pharmacology)
• Nicotinic Agonists (pharmacology)
• Receptors, Nicotinic (metabolism)
• Sodium (metabolism)