Investigating the hedonic effects of interferon-alpha on female rats using brain-stimulation reward

Behav Brain Res. 2007 Feb 12;177(1):90-9. doi: 10.1016/j.bbr.2006.10.033. Epub 2006 Nov 28.


Interferon-alpha (IFN-alpha) is used as a front-line treatment for cancer and other diseases. Reports of depression as a consequence of IFN-alpha therapy scatter the literature, generating interest in the CNS disruptions elicited by this cytokine. In the present work, we investigated the short- and long-term effects of a single systemic injection of vehicle, 10, or 1000 units of IFN-alpha on temperature, body weight, food intake, sickness behaviours, locomotor activity, and brain stimulation reward (BSR) thresholds elicited from the ventral tegmental area in female Long-Evans rats. Pioneered for studying motivational processes, BSR has been exploited as a tool for tracking hedonic status in animal models of depression. In this study, the main findings were that IFN-alpha did not induce anhedonia as defined by no increase in frequency thresholds. However, the analyses of sickness behaviours unveiled a significant increase in piloerection in all sham control animals that received an IFN-alpha injection while the BSR animal scores remained relatively unchanged between pre- and post-injection days. This pattern was also evident in the overall total sickness behaviour scores. Our data suggest that a single exposure to IFN-alpha treatment in female rats elicits long-term somatic effects, without altering hedonic status.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Brain / drug effects*
  • Brain / physiology
  • Dose-Response Relationship, Radiation
  • Electric Stimulation / methods
  • Female
  • Immunologic Factors / pharmacology*
  • Interferon-alpha / pharmacology*
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Motor Activity / radiation effects
  • Rats
  • Rats, Long-Evans
  • Reward*
  • Self Stimulation


  • Immunologic Factors
  • Interferon-alpha