The increase in spontaneous GABA release caused by calcium channel blockers depends on calcium entering the nerve terminal and activating potassium channels; if calcium is chemically trapped inside the cell, the increase in GABA release disappears.
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 intracellular calcium buffering consistently abolishes the paradoxical increase in spontaneous neurotransmitter release following calcium channel blockade across different neuronal types and preparations.
A systematic review and meta-analysis of all studies reporting effects of intracellular calcium buffers (BAPTA-AM, EGTA-AM) on spontaneous GABA or glutamate release frequency following application of calcium channel blockers in central neurons, with standardized timing, concentration, and outcome measures.
Whether intracellular calcium buffering causally prevents the increase in spontaneous GABA release after calcium channel blockade.
A double-blind, randomized, crossover in vitro study using 25+ rat medial preoptic terminals, comparing mIPSC frequency changes after nimodipine (100 μM) in control solution vs. after 20-min pre-incubation with 100 μM BAPTA-AM, with randomization and blinding.
Whether the degree of intracellular calcium buffering correlates with the magnitude of suppression of the nimodipine-induced mIPSC increase.
A longitudinal cohort study measuring mIPSC frequency changes after nimodipine in 40+ rat medial preoptic terminals pre-incubated with varying concentrations of BAPTA-AM (0, 25, 50, 100 μM), correlating the degree of buffering with the percentage reduction in mIPSC increase.
Whether terminals with higher baseline intracellular calcium buffering capacity show a smaller response to calcium channel blockade.
A case-control study comparing 20 terminals with high intrinsic calcium buffering (measured via fluorescent calcium indicators) to 20 with low buffering, measuring the percentage increase in mIPSC frequency after nimodipine application.
Whether the effect of intracellular calcium buffering on the nimodipine-induced mIPSC increase varies across different brain regions in rats.
A cross-sectional survey of mIPSC frequency changes after nimodipine in 30+ rat medial preoptic, hippocampal, and amygdala terminals, each pre-incubated with 100 μM BAPTA-AM, with standardized recording conditions.