HM1-43 is a fixable, activity-dependent fluorescent nerve terminal probe. HM1-43 functions similarly to SynaptoGreen™, but with the additional property of being fixable. Thus, HM1-43 is a useful tool for synapse studies where subsequent fluorescent immunochemistry is desired. HM1-43 and FM®1-43 have identical excitation and emission wavelengths.   FM is a registered trademark of Thermo Fisher Scientific.