SY-002

cf. C.A. 43, 9250b.The acute pulmonary edema which follows administration of NH₄ salts to guinea pigs may be entirely prevented by prior injection of the adrenergic blocking agents, N-(9-fluorenyl)-N-ethyl-β-chloroethylamine-HCl (SKF-501) and N-(2-chloroethyl)-N-ethylbenzohydrylamine-HCl (SY-2).Less marked lung edema is produced in rabbits by NH₄Cl and it is also prevented by these blocking agents.The potent antihistaminic drug, 10-(2-dimethylaminoisopropyl)phenothiazine (phenergan, RP 3277), has no effect on NH₄⁺-induced pulmonary edema, which in this respect as well as in the way it is influenced by adrenergic blocking agents resembles adrenaline-induced pulmonary edema.A central nervous system depressant (continuous ether anesthesia) also prevents the edema.This suggests that adrenergic stimuli of reflex or direct central stimulation plays a part in its production.NH₄ salts produce a marked hyperglycemia, which is not prevented by SKF-501, SY-2, or Et₄NBr.This hyperglycemia is probably unrelated to the edema formation.Some strains of rats and mice are resistant to production of pulmonary edema by NH₄⁺.