ISSN:
1432-2072
Keywords:
Cholinergic System
;
Cholinesterase Activity
;
Tolerance
;
Operant Response
;
Atropine
;
Methylatropine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The development of tolerance during periods of chronically low levels of cholinesterase (ChE) induced by administration of diisopropyl fluorophosphate (DFP) is evidenced in systematic changes in behavioral variables. The present experiment was designed to study the biochemical mechanism(s) involved by challenging tolerant and control subjects with pharmacological agents known to affect the cholinergic system: the cholinolytics, atropine and methylatropine. Measures of the free operant behavior showed tolerance to have developed by the 9th injection of DFP, after which the challenge series began. Clear differences were apparent between the effects of the cholinolytic agents on the tolerant and control groups. Dose-response curves for both groups showed similar trends of decreasing performance with increasing dose level until a critical point was reached. With further increases in dose, there was a complete absence of responding in the majority of tolerant subjects, while control animals continued to perform at about 40 per cent normal. The fact that effects of the methylatropine challenge were not significantly different in tolerant and control subjects implies that the biochemical process(es) of tolerance had a major central component.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00404056
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