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Effects of single or repeated administration of a carbamate, propoxur, and an organophosphate, DDVP, on jejunal cholinergic activities and contractile responses in rats
Author(s) -
Kobayashi Haruo,
Sato Itaru,
Suzuki Tadahiko,
Matsusaka Naonori,
Yuyama Akira,
Akatsu Yasuhiko,
Fujii ShinIchiro
Publication year - 1994
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.2550140307
Subject(s) - oxotremorine , propoxur , muscarinic acetylcholine receptor , atropine , chemistry , cholinesterase , organophosphate , acetylcholine , cholinergic , dichlorvos , endocrinology , acetylcholinesterase , medicine , pharmacology , biochemistry , receptor , biology , pesticide , enzyme , agronomy
Wistar rats were injected once or repeatedly for 10 days with dichlorvos (DDVP, 5 mg kg −1 ), propoxur (10 mg kg −1 ), oxotremorine (0.1 mg kg −1 ) or atropine (5 mg kg −1 ). Animals were killed 20 min or 24 h after single or consecutive injections, respectively, for determinations of cholinergic activities and contractile responses to acetylcholine (ACh) of the jejunum. Single treatments: while DDVP and propoxur decreased acetylcholinesterase (AChE) activity, oxotremorine and atropine did not. Although DDVP, propoxur and oxotremorine increased levels of ACh, atropine decreased them. Contractile responses to ACh were enhanced by DDVP and reduced by oxotremorine and atropine. The B max value of binding of [ 3 H]quinuclidinyl benzylate (QNB) to muscarinic ACh receptors was decreased by atropine. Consecutive treatments: DDVP and oxotremorine decreased AChE activity markedly and slightly, respectively. Although DDVP and oxotremorine increased levels of ACh, propoxur decreased them. Without affecting the contractile responses, DDVP caused a reduction and propoxur and atropine caused an increase in the B max value for binding of [ 3 H]QNB. Both the contractile responses and the value of B max for binding of [ 3 H]‐QNB were decreased by oxotremorine. In summary, propoxur and DDVP showed similar effects mainly through their anticholinesterase properties in the case of single injection, but DDVP had similar effects to those of oxotremorine and propoxur had similar effects to those of atropine in the case of repeated injection.