Abstract
Fluctuation in the amplitude of a synaptic response were first reported at the neuromuscular junction (NMJ) and then these phenomenon were observed at the synapses in the central nervous system (CNS). These fluctuations were led to the ‘quantal’ hypothesis of transmitter release and has been used for many studies of synaptic function and plasticity. On the other hand, nonstationary noise analysis were developed to estimate the single channel conductances both in the excitable and postsynaptic membrane of the neurons. Furthermore, this analysis for estimating single channel conductances has been extended to the amplitude-variance of synaptic responses around the mean-value of synaptic currents. The experimental, graphical and analytical approach, which is less sensitive to recording noise than previous techniques, was developed by others under fewer assumptions. We also developed a non-stationary analysis of the fluctuations in postsynaptic response amplitudes that was performed before and after the toxin had acted or during toxin action. In the present study, the principle of this modified version of nonstationary fluctuation analysis is described and experimental results obtained from inhibitory cholinergic synapses in dissected buccal ganglia of Aplysia are discussed applying this analytical method. [Jpn J Physiol 55 Suppl:S152 (2005)]
