Office of News and Information Johns Hopkins University 3003 N.
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(410) 516-7160 / Fax (410) 516-5251 September 15, 1999 EMBARGOED
FOR RELEASE ON WEDNESDAY, SEPT. 15, 1999 Brain Chemical Mellows
Male Mice, A chemical messenger in the brain that dramatically
decreases aggressive behavior in male mice appears, on the
contrary, to be essential to a mother mouse's ability to lash
out at strange mice in defense of her pups, according to a new
report by scientists at The Johns Hopkins University. Makes
Mouse Mothers Tough The new results, reported in the September
15 issue of the Journal of Neuroscience, establish a potential
link between a single brain chemical the neurotransmitter nitric
oxide and opposing effects in male versus female brains. "This
result was a big surprise, given what we saw in the male mice,"
says Stephen Gammie, a postdoctoral fellow in the Department of
Psychology at Johns Hopkins and lead author of the paper. "This
may reflect th