POSTSYNAPTIC MECHANISMS IN SYNAPTIC PLASTICITY

Abstract

Publisher Summary Sympathetic ganglion has been used as a model for studying the physiology and pharmacology of neurons and synapses. Recently, the sympathetic ganglion of the bullfrog has been found to be well suited for such studies. A long-lasting modulation of the efficacy of synaptic transmission has been found to be associated with changes in the membrane properties of the neurons. Membrane permeability changes that may be related to the regulation of synaptic excitability have been studied. Several factors may contribute to the ability of a fast excitatory postsynaptic potential (EPSP) to elicit an action potential in the postsynaptic neuron and transmit information, as nerve impulses, across the synapse. It has been found that certain types of neurotransmitter actions are capable of producing a long-lasting enhancement of the ability of fast EPSPs to initiate postsynaptic action potentials. Long-lasting PSPs generated by decreases in membrane permeability are capable of augmenting the efficacy of transmission at synapses. The enhancement of fast EPSP amplitude increases the probability of postsynaptic action potential generation, thus increasing the efficacy of impulse transmission at the synapse. The stimulation of one synaptic pathway is capable of increasing the efficacy of synaptic transmission in a second synaptic pathway by a postsynaptic mechanism.