Dynorphin A (1-10) (TFA)

Dynorphin A (1-10) (TFA), an endogenous opioid neuropeptide, binds to extracellular loop 2 of the κ-opioid receptor. Dynorphin A (1-10) (TFA) also blocks NMDA-activated current with an IC₅₀ of 42.0 μM. IC50 & Target: κ-opioid receptor^[1]
IC50: 42.0 μM (NMDA receptor)^[2] In Vitro: Dynorphin A (1-10) (TFA), an endogenous opioid neuropeptide, binds in the transmembrane domain of the κ-receptor^[1]. The non-opioid actions of various forms of Dynorphin A (DynA) are examined on N-methyl-D-aspartate (NMDA) receptor channels in isolated rat trigeminal neurons using the whole-cell patch recording technique. All the dynorphins tested blocked NMDA-activated currents. The blocking actions are voltage-independent. The IC₅₀ is 42.0 μM for DynA(1-10). To determine if shorter dynorphins have the similar blocking property, we examined the action of DynA(1-10) at different membrane potentials. DynA(1-10) blocks I_NMDA to a similar extent as the membrane potentials changed from -80 to +60 mV. Thus, despite a 160-fold difference in the apparent affinities, DynA(1-32) and DynA(1-10) both exert voltage-independent actions on NMDA receptors^[2].