Interaction of histamine H2-receptor blocking drugs with the noradrenergic system in rat brain and heart.

The i.v.t. injection of burimamide (BUR), 50 micrograms, or cimetidine (CIM), 250 micrograms, decreased significantly the hypothalamic noradrenaline (NA) content by 32 and 21%, and significantly increased the whole brain 3-methoxy-4-hydroxyphenylglycol level by 46 and 28%, respectively. The i.p. administration of BUR or metiamide (MET), at a dose of 50 mg/kg, caused a decrease in the rat heart NA content by 34 and 21%, respectively; CIM had no effect at doses up to 100 mg/kg i.p., whether given acutely or chronically.