Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by NOSTRANDT, A. C.
Right arrow Articles by PADILLA, S.
Right arrow Search for Related Content
PubMed
Right arrow Articles by NOSTRANDT, A. C.
Right arrow Articles by PADILLA, S.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 1993 Oxford University Press

research-article

A Modified Spectrophotometric Method Appropriate for Measuring Cholinesterase Activity in Tissue from Carbaryl-Treated Animals

A. C. NOSTRANDT*,1, J. A. DUNCAN{dagger} and S. PADILLA{ddagger}

*Curriculum in Toxicology, University of North Carolina at Chapel Hill Chapel Hill, North Carolina 27599 {dagger}University of Texas Southwestern Medical School 5323 Harry Hines Boulevard, Dallas, Texas 75235-9033 {ddagger}Cellular and Molecular Toxicology Branch, Neurotoxicology Division (MD-74B), Health Effects Research Laboratory, U.S Environmental Protection Agency Research Triangle Park, North Carolina 27711

Received January 19, 1993; accepted April 26, 1993

Inhibited cholinesterase in tissues of animals exposed to carbamate pesticides is known to reactivate readily, presenting considerable problems in the accurate assessment of cholinesterase activity in these tissues. Decarbamylation of cholinesterase is favored when the tissue samples are diluted and/or are incubated for an extended time. The present study was performed to identify modifications of the commonly used spectrophotometric assay for cholinesterase activity that would minimize spontaneous reactivation of enzyme activity. Those modifications included preincubation of concentrated tissue with concentrated chromogen (i.e., DTNB), dilution to final reaction volume immediately before measurement, and measurement of cholinesterase over a short period of time (5–10 min). The Ellman assay with and without modifications was performed using a microtiter plate reader on tissues from carbaryl-treated rats: undiluted plasma, diluted erythrocytes (1:25), minimally diluted erythrocytes (1:2), diluted brain (1:100), or minimally diluted brain (1:2). The results were compared to cholinesterase activities obtained using a radiometnic method which employs minimally diluted tissue and short incubation times. The degree of cholinesterase inhibition for undiluted or minimally diluted tissue assayed by the modified method agreed with those obtained using the radiometric method. Even if the tissues were diluted immediately before assay, however, significant reactivation occurred by the time the first measurements were made by the conventional method. Furthermore, significant spontaneous reactivation may still occur using the modified method if the assay is run for more than 10 min. Use of this modified Ellman method will enable more accurate estimation of in vivo cholinesterase activity in animals treated with carbamates.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.