Histamine paw edema of mice was increased and became H2-antagonist sensitive by co-injection of nitric oxide forming agents, but serotonin paw edema was decreased

摘要: Abstract Nitric oxide (NO) suprisingly caused the opposite effect on histamine and serotonin edema. The local injection of acidified nitrite (0.3–30 μg /paw which correspond to 10 μg−1mg/kg) increased edema mice up 45±4% suppressed 90±3%. Other NO-generators (nitroprusside sodium hydroxylamine) showed similar effects. These results were in accordance with our previous data endogenous NO. Methylene blue (MB, 30ng/paw corresponds 1 μg/kg) (62±3%) (43±3%) normal mice, being reversed by nitrite. This suggests involvement o guanosine 3′, 5′ -cyclic monophosphate (cGMP) formation for action Histamine became sensitive H2-antagonist, cimetidine, co-injection 30 μg/paw (which 1mg/kg) (ED50=30 μg/kg versus ⪢ 1mg/kg). NO seemed modify receptor(s) or tautomeric form histamine. NO, O2− other oxyradicals might finely control vascular permeability together inflammatory mediators.