animals of both sexes , at 5 or 20 days of age , were injected into the lateral brain ventricles with three log-doses of histamine ( ha ) , 2,2 , pyridilethylamine ( 2 pea , and h1-histamine agonist ) , 4 methyl-histamine ( 4 mha , an h2-histamine agonist ) or saline as control .
C0025779
methyl-histamine
C0019588
histamine