NIAX catalyst ESN: subchronic neuropharmacology and neurotoxicology

NIAX catalyst ESN (a mixture of 95% DMAPN/dimethylamino-proprionitrile and 5% A-99/bis-dimethylaminoethyl ether) was a catalyst used in the production of polyurethan foam which was reported to produce a reversible peripheral neuropathy in workers exposed to it. ESN and its two components were tested by a variety of short term tests for neurologic activity. In vivo (rat and mouse) and in vitro (isolated tissue) assays were employed. Both ESN and DMAPN at dose levels of 0.25 ml/kg IP (intraperitoneally) produced tremors, convulsions, and cardiovascular effects in rats and mice. At doses as low as 0.01 ml/kg both ESN and DMAPN also induced a loss of micturition reflex in rats. A-99, though more lethal, caused no neurologic or reflex effects at doses up to 1.0 ml/kg. DMAPN was concluded to be the causative agent.