Handling stress impairs learning through a mechanism involving caspase-1 activation and adenosine signaling

Albert E. Towers, Maci L. Oelschlager, Madelyn Lorenz, Stephen J. Gainey, Robert H. McCusker, Steven A. Krauklis, Gregory G. Freund

Research output: Contribution to journalArticlepeer-review


Acute stressors can induce fear and physiologic responses that prepare the body to protect from danger. A key component of this response is immune system readiness. In particular, inflammasome activation appears critical to linking stress to the immune system. Here, we show that a novel combination of handling procedures used regularly in mouse research impairs novel object recognition (NOR) and activates caspase-1 in the amygdala. In male mice, this handling-stress paradigm combined weighing, scruffing and sham abdominal injection once per hr. While one round of weigh/scruff/needle-stick had no impact on NOR, two rounds compromised NOR without impacting location memory or anxiety-like behaviors. Caspase-1 knockout (KO), IL-1 receptor 1 (IL-1R1) KO and IL-1 receptor antagonist (IL-RA)-administered mice were resistant to handling stress-induced loss of NOR. In addition, examination of the brain showed that handling stress increased caspase-1 activity 85% in the amygdala without impacting hippocampal caspase-1 activity. To delineate danger signals relevant to handling stress, caffeine-administered and adenosine 2A receptor (A2AR) KO mice were tested and found resistant to impaired learning and caspase-1 activation. Finally, mice treated with the β-adrenergic receptor antagonist, propranolol, were resistant to handling stress-induced loss of NOR and caspase-1 activation. Taken together, these results indicate that handling stress-induced impairment of object learning is reliant on a pathway requiring A2AR-dependent activation of caspase-1 in the amygdala that appears contingent on β-adrenergic receptor functionality.

Original languageEnglish (US)
Pages (from-to)763-776
Number of pages14
JournalBrain, Behavior, and Immunity
StatePublished - Aug 2019


  • Adenosine
  • Amygdala
  • Caffeine
  • Caspase-1
  • Learning
  • Stress
  • β-Adrenergic receptor

ASJC Scopus subject areas

  • Immunology
  • Endocrine and Autonomic Systems
  • Behavioral Neuroscience


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