Gap 19 (trifluoroacetate salt)

Gap 19 is a nonapeptide derivative of connexin43 (Cx43) and an inhibitor of Cx43 hemichannels.^1,2 It suppresses the membrane charge transfer (Q_m) in HeLa cells expressing Cx43 (IC₅₀ = ~6.5 µM), as well as Cx43 hemichannel currents in isolated guinea pig cardiomyocytes when used at a concentration of 100 µM.¹ Gap 19 inhibits glutamate-induced ATP release, a marker of Cx43 hemichannel activity, in primary mouse astrocytes.² In vivo, Gap 19 (300 µg/kg, i.c.v.) decreases cortical neuronal loss, infarct volume, and the number of errors in a foot fault test in a mouse model of cerebral ischemia and reperfusion injury induced by middle cerebral artery occlusion (MCAO).³ It also reduces infarct size in a mouse model of myocardial ischemia and reperfusion injury induced by ligation of the left anterior descending (LAD) artery when administered at a dose of 25 mg/kg.¹