MrIC, a Novel α-Conotoxin Agonist in the Presence of PNU at Endogenous α7 Nicotinic Acetylcholine Receptors

alpha-Conotoxins are competitive antagonists of nicotinic acetylcholine receptors (nAChRs). Their high selectivity and affinity for the various subtypes of nAChRs have led to significant advances in our understanding of the structure and function of these key ion channels. Here we report the discovery of a novel 4/7 alpha-conotoxin, MrIC from the venom duct of Conus marmoreus, which acts as an agonist at the endogenous human alpha 7 nAChR in SH-SY5Y cells pretreated with PNU120596 (PNU). This unique agonist activity of MrIC at alpha 7 nAChRs may guide the development of novel alpha 7 nAChR modulators.