Acute effects of corticosterone on LiCl-induced rapid gustatory conditioning in rats: a taste reactivity analysis.

Previous research has shown that acute corticosterone treatment can have rapid effects on learning and memory. Using the taste reactivity test (TRT), the present study examined the effect of acute administration of corticosterone on sucrose palatability and the development of LiCl-induced rapid gustatory conditioning. On each of two conditioning days rats were injected with either a low dose of lithium chloride (LiCl; 0.75 mEq, i.p.) or saline (NaCl; 0.9%, i.p.) and 10 min later, received a second injection of either corticosterone (5 mg/kg, i.p.) or cyclodextrin vehicle. Rats were then placed in the TRT chamber, where 1 min intraoral infusions of sucrose (0.3 M) were delivered every 10 min. Taste reactivity responses were videotaped and later analyzed for frequency of occurrence. Rats treated with both LiCl and corticosterone showed enhanced aversive responding and reduced ingestive responding relative to control rats treated with LiCl and vehicle. The implication that corticosterone may have a rapid enhancing effect on gustatory conditioning is discussed.