Lupus Antibodies Alter Emotional Responses in Mice

Neuronal death in amygdala key to effect

THURSDAY, Jan. 5 (HealthDay News) -- Autoantibodies commonly found in systemic lupus erythematosus (SLE) can alter not only memory but also emotional responses in mice if they cross the blood-brain barrier and target the amygdala, according to findings published in the Proceedings of the National Academy of Sciences Early Edition.

Betty Diamond, M.D., of Columbia University Medical Center in New York City, and colleagues found that mice expressing SLE-like autoantibodies suffer neuronal death in the amygdala if the blood-brain barrier is breached by epinephrine. Previous studies have shown that SLE antibodies can affect memory if the blood-brain barrier is breached in the region of the hippocampus by lipopolysaccharide.

Epinephrine specifically influences blood flow in the amygdala, a region known to control Pavlovian fear conditioning. The authors found that the SLE-model mice treated with epinephrine showed excessive neuronal death in the amygdala and responded poorly to a tonal/foot shock fear response test. No differences were seen in a maze test of memory, which is governed by the hippocampus.

"It will be of interest to determine by [functional magnetic resonance imaging] whether lupus patients fail to respond to subliminal fear stimuli. This failure might suggest a selective loss of neurons in the basal lateral amygdala similar to the loss observed in our murine model," the authors write.

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