THE IMPACT OF RECEPTOR DESENSITIZATION ON FAST SYNAPTIC TRANSMISSION

The role of desensitization of ligand-gated channels at fast chemical synapses has been difficult to establish. Desensitization has been stu died traditionally with prolonged agonist exposure, whereas the durati on of free neurotransmitter in the synaptic cleft is relatively brief. Studies of acetylcholine-, glutamate- and GABA-gated channels using r apid agonist application now provide a means to assess the effects of desensitization in shaping synaptic responses and in influencing neuro nal excitability. These data reveal several strikingly different patte rns by which the receptor-specific kinetics of desensitization can det ermine the size, timecourse and frequency of transmitted signals. Dese nsitization is thus a surprisingly versatile mechanism for shaping syn aptic transmission.