Lithium alters measures of auditory gating in two strains of mice.

ABSTRACT

BACKGROUND: There are similarities between schizophrenia and bipolar disorder, especially during the psychotic phase. Auditory gating deficits are common in both schizophrenia (does not remit postpsychotic event) and bipolar disorder (only during the manic phase). Lithium has been used to treat psychosis acutely in both bipolar disorder and schizophrenia. An animal model was used to assess the effects of lithium treatment on normal and deficient auditory gating. METHODS: Mice of the DBA/2 (deficient gating) and C3H (normal gating) strains were treated for 6 weeks with either standard rodent chow or rodent chow supplemented with 2.55g/kg lithium carbonate. After 6 weeks of treatment, auditory evoked potentials were recorded under anesthesia. Differences between the groups and treatments were determined using analysis of variance. RESULTS: The normally impaired DBA/2 mice showed improved auditory gating following lithium treatment, while the C3H mice, the benchmark "normal" mouse strain, were impaired after lithium treatment. CONCLUSIONS: C3H mice treated with lithium had significantly impaired auditory gating as a result of treatment. This may be due to norepinephrine facilitation, through a blockade of presynaptic alpha(2) autoreceptors. DBA/2 mice had improved gating as a result of treatment with lithium, likely due to improved functioning of the gamma-aminobutyric acid system.