In rat nerve terminals, calcium channels that control spontaneous GABA release are located farther from the release site than those that trigger evoked release; blockers reach the spontaneous-release channels first, increasing GABA release without stopping evoked release.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether the differential kinetics of calcium channel blocker effects on spontaneous vs. evoked release is a consistent phenomenon across synapses and whether it correlates with synaptic ultrastructure.
A systematic review and meta-analysis of all studies reporting time-to-peak effects of calcium channel blockers on spontaneous and evoked neurotransmitter release in central synapses, with correlation to synaptic cleft width and density of extracellular matrix proteins.
Whether artificially increasing diffusion barrier thickness reduces the speed of spontaneous release increase after calcium channel blockade.
A double-blind, randomized, crossover in vitro study using 20+ rat medial preoptic terminals, comparing the time-to-peak mIPSC increase after nimodipine (100 μM) under normal conditions vs. after pre-treatment with a synthetic extracellular matrix polymer (e.g., hyaluronic acid) to artificially increase diffusion barrier thickness.
Whether the time delay between spontaneous release increase and evoked release inhibition correlates with synaptic cleft width in individual terminals.
A longitudinal cohort study measuring the time-to-peak mIPSC increase and time-to-inhibition of evoked release after ω-conotoxin MVIIC in 30+ rat medial preoptic terminals, while simultaneously quantifying synaptic cleft width via electron microscopy in the same cells.
Whether terminals with wider synaptic clefts show slower onset of spontaneous release increase after calcium channel blockade compared to terminals with narrow clefts.
A case-control study comparing 20 terminals with wide synaptic clefts (>30 nm) to 20 with narrow clefts (<15 nm), measuring the time-to-peak mIPSC increase after 1 μM ω-conotoxin MVIIC.
Whether the kinetic difference between spontaneous and evoked release effects varies across brain regions with different synaptic ultrastructure.
A cross-sectional survey comparing time-to-peak mIPSC increase and time-to-inhibition of evoked release after 1 μM ω-conotoxin MVIIC in 30+ rat terminals from medial preoptic, hippocampal, and cerebellar regions, with standardized EM analysis of cleft width.