Recording and analyzing synaptic currents and synaptic potentials

Intracellular recording of synaptic currents (PSCs) under voltage clamp conditions provides the most accurate and direct means for measuring the earliest effects of neurotransmitters. With this tool, combined with pharmacological or ionic manipulations, one can obtain information about the type of transmitter used at a synapse, the dynamics of transmitter-receptor interactions, the types and numbers of receptors activated, the effects of drugs on transmission, functional neural circuitry, and indications about the mechanisms of synaptic plasticity. Each synaptic current or potential is a reflection of many experimental variables: the ionic composition of the solutions, the temperature, the presence of pharmacological agents, the rate of synaptic stimulation, the history of stimulation, the variables of the recording system, as well as other factors unique to each preparation. Correct analysis of data requires all these parameters be considered. Both stimulus-evoked and spontaneous synaptic events are covered in this unit since conclusions about synaptic and drug mechanisms are strongest when based upon recording of both types of activity. This unit outlines basic considerations for recording PSCs and PSPs in addition to guidelines for data analysis.