Vitamin C deficiency in osteogenic disorder Shionogi/Shi Jcl-od/od rats: effects on sour taste preferences, lick rates, chorda tympani nerve responses, and taste transduction elements.

This article focuses on how vitamin C (ascorbic acid; AA) deficiency affects sour taste perception and related neural and molecular mechanisms in osteogenic disorder Shionogi/Shi Jcl-od/od (od/od) rats, which cannot synthesize AA. Behavioral tests showed that AA-deficient rats exhibited increased preference and licking responses to sour solutions, including AA and citric acid, compared to AA-replete rats. Electrophysiological recordings revealed that chorda tympani nerve responses to organic acids were significantly reduced in AA-deficient rats, despite no change in the number of fungiform papillae taste buds. Molecular analyses indicated downregulation of certain taste-related genes (e.g., Gnat3, Trpm5, Tas1r1, Car4, Gad1) in taste bud cells during AA deficiency, while expression of putative sour taste receptors remained unchanged. These findings suggest that AA deficiency diminishes aversive sour taste sensitivity by altering peripheral taste signaling, potentially promoting increased intake of AA-containing foods.