Exogenous calcium protects postweanling rats from salicylate-induced changes in auditory conditioning

Abstract

During Days 26–32 (postnatal), 18 rats drank more of a 0.05-M calcium-enriched solution when it was given to them ad lib or 1 h daily, but not when it was given 15 min daily, compared with 18 pups with similar access to plain water only. In a second experiment, acquisition and extinction of auditory conditioned suppression were observed in thirty-six 25-day-old pups, half of them reared with the calcium supplement throughout gestation and preweanling, and the other half reared with tap water. Twenty-two hours before training, the subjects were fluid deprived and exposed to continuous noise of 60 dB (SPL). Two hours prior to each session, the subjects received either injections of sodium salicylate before both sessions (n = 6 for each fluid type), saline before acquisition and salicylate before the extinction session (n= 6), or saline before both sessions (n = 6). Suppression of the approach to drink at the end of an alleyway paired the offset of the 60-dB noise and footshock. Calcium afforded subjects protection from salicylate-induced changes in auditory behavior during both acquisition and extinction.