Agonist potency determination by patch clamp analysis of single glutamate receptors

Agonists (L-quisqualate, L-glutamate and L-cysteine sulphinate) of the locust muscle glutamate receptor differ in potency. Patch clamp analysis of single glutamate receptors reveals that the relative potencies of agonists are determined both by the life-times of the channels that they gate and their probability of activating the glutamate receptor-ionophore complex. Furthermore, agonists which most readily activate the receptor channel complex gate channels with longer life-times than agonists which are less efficient in this respect.