Strain Differences in the Somnogenic Effects of Interferon Inducers in Mice

Abstract

Increased slow-wave sleep accompanies influenza infection in C57BL/6 mice but not BALB/c mice. These strains of mice possess different alleles of the genetic locus If-1, which codes for high (If-l ^h; C57BL/6) and low (If-1 ¹; BALB/c) production of interferon (IFN), a putative sleep-inducing cytokine. To evaluate the contribution of the If-1 gene to differences in murine sleep propensity, sleep patterns were evaluated in mice treated with the IFN inducers polyinosinic:polycytidilic acid (pIC) or Newcastle disease virus (NDV), with influenza virus, or with murine interferon (IFN-α) or IFN-α/ β. As compared with baseline values, C57BL/6 mice exhibited increased slow-wave sleep after all three challenges, but BALB/c mice did not. Congenie B6.C-H28^c mice, which bear the BALB/c allele for low IFN production on the C57BL/6 genetic background, showed enhanced slow-wave sleep after influenza infection but not after NDV. Exogenous IFN did not enhance slowwave sleep in either C57BL/6 or BALB/c mice. These data suggest that the If-1 allele may influence the somnogenic responsiveness of mice under some conditions but that additional mechanisms may contribute to sleep enhancement during infectious disease.