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RELATIONSHIP OF NEUROPATHY TARGET ESTERASE INHIBITION TO NEUROPATHOLOGY AND ATAXIA IN HENS GIVEN ORGANOPHOSPHORUS ESTERS
Citation:
Ehrich, M., B. Jornter, AND S. Padilla. RELATIONSHIP OF NEUROPATHY TARGET ESTERASE INHIBITION TO NEUROPATHOLOGY AND ATAXIA IN HENS GIVEN ORGANOPHOSPHORUS ESTERS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/030.
Description:
Adult WhiteLeghorn hens were acutely exposed to 3 dosages of the following organophosphorus esters: mipafox, tri-ortho-tolyl phosphate (TOTP), penyl saligenin phosphate, diisppropylophosphoro-fluoridate (DFP), malathion and dichlorvos. europathy target esterase (NTE) activity was measured in brain and spinal cord 4 or 48 hr after exposure, ataxia was assessed using an 8-point rating scale days 9 through 21 after administration, and neuropathological examination was conducted on samples collected from perfusion-fixed animals on day 21. orphological alterations were indicated by lesion scores between 0 (no lesions) and 4 (diffuse involvement of spinal cord tracts and 25% degeneration of peripheral never fibers). osages of mipafox (30 mg/kg ip), TOTP (500 mg/kg po), phenyl saligenin phosphate (2.5 mg/kg im) and DFP (1 mg/kg sc) that were capable of inhibiting NTE >80% in both brain and spinal cord preceded ataxia which reached maximal levels (scores of 7-8), and development of lesions scored as 4. Inhibition of NTE over 55% could not be reached in hens given malathion or dichlorvos without causing lethality even with atropine protection, and no significant ataxia or lesions developed in those birds. ens were notably clinically impaired (ataxia scores of 3-4) 21 days after administration of dosages of mipafox (3 and 6 mg/kg), TOTP f@90 mg/kg), phenyl saligenin phosphate (0.1 and 0.2 mg/kg), and DFP (0.4 mg/kg) when spinal cord NTE was inhibited 40-75%. esions were, however, only noted in spinal cord and peripheral nerves of hens given TOTP or DFP (scores 1-3).