Variations in amplitude and time course of inhibitory postsynaptic currents

• DOI: 10.1152/jn.1986.56.5.1424
• Publication Date: 2017-12-24T17:45:03Z
• Authors: D. Gardner
• Keywords: Time constant; Aplysia; Post-tetanic potentiation

In order to examine the relative contributions of changes in amplitude and time course synaptic plasticity, variations peak constant decay have been analyzed from inhibitory postsynaptic currents (PSC) recorded voltage-clamped Aplysia buccal ganglia neurons. these cells, with single can be low noise under well-controlled space clamp. Over a population 36 neurons, duration was more narrowly distributed than amplitude, but each varied. The coefficient variation (CV) 0.21 for (tau) 0.87 conductance (g peak). Population variances are larger accounted by such variables as temperature suggesting that functional modifications alter determinants effectiveness over long term. Recordings up several hundred PSC 16 neurons show both cell vary independently short spans. Decay remained exponential changed. CV tau averaged 0.11; g 0.19. Variability not an artifact amplitude; relatively uncorrelated current amplitudes or sample size. Smoothing adding excess individual set produced only small CV, showing variability noise. Several specific manipulations presynaptic neuron altered course. Tetanic stimulation short-term potentiation subsequent PSCs. Peak increased 80%; 12%. Reducing interspike intervals 10 1 s habituation course, decreasing 35 40% 10%. Conditioning DC depolarization enhanced little effect on constant. Although plastic affect duration, is alterable. Parallel synergistically charge transfer, therefore efficacy. Similar mechanisms may produce long-term differences seen between