The nitromethylene heterocycle 1-(pyridin-3-yl-methyl)-2-nitromethylene-imidazolidine distinguishes mammalian from insect nicotinic receptor subtypes.

Effects of the insecticidal compound 1-(pyridin-3-yl-methyl)-2-nitromethylene-imidazolidine (PMNI) on different subtypes of the nicotinic acetylcholine receptor were studied in voltage-clamped locust thoracic ganglion neurons, mouse BC3H1 muscle cells and mouse N1E-115 neuroblastoma cells. In locust neurons 10 microM PMNI induced agonistic effects and subsequent complete block of 1 mM acetylcholine-induced inward currents. The same concentration of PMNI produced no significant agonistic and antagonistic effects on the endplate type nicotinic receptor in BC3H1 cells. Neuronal type nicotinic receptor operated ion currents in N1E-115 cells were blocked by 10 microM PMNI to 50% of the control value, while agonistic effects were not observed. The differential action of PMNI designates this compound as a potential new tool to distinguish between subtypes of the nicotinic acetylcholine receptor.