In mouse olfactory nerves, a small drop in calcium entering the nerve terminal causes a much larger drop in neurotransmitter release—halving calcium reduces output by 80%, making the system highly sensitive to small changes in calcium levels.
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 superlinear calcium-release coupling is a universal feature of primary sensory afferents and whether its cooperativity coefficient varies systematically across sensory modalities.
A systematic review and meta-analysis of all studies measuring the Hill coefficient for calcium-dependent neurotransmitter release in primary sensory neurons (olfactory, retinal, auditory, somatosensory) across species, using standardized methods of calcium imaging and vesicle release reporters.
Whether pharmacologically altering calcium channel density or vesicle fusion machinery changes the cooperativity of release in olfactory neurons.
A double-blind, randomized trial in 24 OMP-spH mice, randomized to intranasal infusion of ω-conotoxin (to reduce N-type channels), botulinum toxin (to impair vesicle fusion), or saline, with in vitro calcium and spH imaging to measure changes in Hill coefficient and maximal release.
Whether the cooperativity of calcium-release coupling in olfactory neurons predicts individual differences in odor sensitivity across a population.
A prospective cohort study of 100 healthy adults, measuring olfactory sensitivity thresholds and correlating them with the Hill coefficient of calcium-release coupling estimated via fMRI adaptation paradigms during repeated odor exposure.
Whether individuals with hyposmia show altered cooperativity of calcium-release coupling in olfactory neurons compared to controls.
A case-control study comparing the Hill coefficient of calcium-release coupling in olfactory bulb slices from 15 individuals with post-viral hyposmia and 15 age-matched controls, using paired calcium and synaptopHluorin imaging under controlled [Ca2+] conditions.
Whether the superlinear relationship between calcium influx and release is consistent across different glomeruli in the mouse olfactory bulb.
A cross-sectional analysis of 60 glomeruli in 20 mouse olfactory bulb slices, measuring calcium influx and synaptopHluorin release across a range of external calcium concentrations (0.25–4 mM) and calculating the Hill coefficient for each glomerulus to assess variability.