PMID- 22436584
OWN - NLM
STAT- MEDLINE
DCOM- 20120920
LR  - 20131121
IS  - 1879-1298 (Electronic)
IS  - 0045-6535 (Linking)
VI  - 88
IP  - 4
DP  - 2012 Jul
TI  - Binary mixtures of azinphos-methyl oxon and chlorpyrifos oxon produce in vitro 
      synergistic cholinesterase inhibition in Planorbarius corneus.
PG  - 450-8
LID - 10.1016/j.chemosphere.2012.02.069 [doi]
AB  - In this study, the cholinesterase (ChE) and carboxylesterase (CES) activities 
      present in whole organism homogenates from Planorbarius corneus and their in 
      vitro sensitivity to organophosphorous (OP) pesticides were studied. Firstly, a 
      characterization of ChE and CES activities using different substrates and 
      selective inhibitors was performed. Secondly, the effects of azinphos-methyl oxon 
      (AZM-oxon) and chlorpyrifos oxon (CPF-oxon), the active oxygen analogs of the OP 
      insecticides AZM and CPF, on ChE and CES activities were evaluated. Finally, it 
      was analyzed whether binary mixtures of the pesticide oxons cause additive, 
      antagonistic or synergistic ChE inhibition in P. corneus homogenates. The results 
      showed that the extracts of P. corneus preferentially hydrolyzed 
      acetylthiocholine (AcSCh) over propionylthiocholine (PrSCh) and 
      butyrylthiocholine (BuSCh). Besides, AcSCh hydrolyzing activity was inhibited by 
      low concentrations of BW284c51, a selective inhibitor of AChE activity, and also 
      by high concentrations of substrate. These facts suggest the presence of a 
      typical AChE activity in this species. However, the different dose-response 
      curves observed with BW284c51 when using PrSCh or BuSCh instead of AcSCh suggest 
      the presence of at least another ChE activity. This would probably correspond to 
      an atypical BuChE. Regarding CES activity, the highest specific activity was 
      obtained when using 2-naphthyl acetate (2-NA), followed by 1-naphthyl acetate 
      (1-NA); p-nitrophenyl acetate (p-NPA), and p-nitrophenyl butyrate (p-NPB). The 
      comparison of the IC(50) values revealed that, regardless of the substrate used, 
      CES activity was approximately one order of magnitude more sensitive to AZM-oxon 
      than ChE activity. Although ChE activity was very sensitive to CPF-oxon, CES 
      activity measured with 1-NA, 2-NA, and p-NPA was poorly inhibited by this 
      pesticide. In contrast, CES activity measured with p-NPB was equally sensitive to 
      CPF-oxon than ChE activity. Several specific binary combinations of AZM-oxon and 
      CPF-oxon caused a synergistic effect on the ChE inhibition in P. corneus 
      homogenates. The degree of synergism tended to increase as the ratio of AZM-oxon 
      to CPF-oxon decreased. These results suggest that synergism is likely to occur in 
      P. corneus snails exposed in vivo to binary mixtures of the OPs AZM and CPF.
CI  - Copyright (c) 2012 Elsevier Ltd. All rights reserved.
FAU - Cacciatore, Luis Claudio
AU  - Cacciatore LC
AD  - Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, 
      Universidad de Buenos Aires, Ciudad Universitaria, Nunez, 1428 Buenos Aires, 
      Argentina.
FAU - Kristoff, Gisela
AU  - Kristoff G
FAU - Verrengia Guerrero, Noemi R
AU  - Verrengia Guerrero NR
FAU - Cochon, Adriana C
AU  - Cochon AC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120319
PL  - England
TA  - Chemosphere
JT  - Chemosphere
JID - 0320657
RN  - 0 (Cholinesterase Inhibitors)
RN  - 0 (Pesticides)
RN  - 265842EWUV (Azinphosmethyl)
RN  - EC 3.1.1.1 (Carboxylesterase)
RN  - EC 3.1.1.8 (Cholinesterases)
RN  - JCS58I644W (Chlorpyrifos)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Acanthaceae/*enzymology
MH  - Azinphosmethyl/*analogs & derivatives/*pharmacology
MH  - Carboxylesterase/antagonists & inhibitors/metabolism
MH  - Chlorpyrifos/*analogs & derivatives/*pharmacology
MH  - Cholinesterase Inhibitors/chemistry/pharmacology
MH  - Cholinesterases/*metabolism
MH  - Drug Synergism
MH  - Oxygen/*chemistry
MH  - Pesticides/chemistry/pharmacology
EDAT- 2012/03/23 06:00
MHDA- 2012/09/21 06:00
CRDT- 2012/03/23 06:00
PHST- 2011/06/11 00:00 [received]
PHST- 2012/01/31 00:00 [revised]
PHST- 2012/02/17 00:00 [accepted]
PHST- 2012/03/23 06:00 [entrez]
PHST- 2012/03/23 06:00 [pubmed]
PHST- 2012/09/21 06:00 [medline]
AID - S0045-6535(12)00283-4 [pii]
AID - 10.1016/j.chemosphere.2012.02.069 [doi]
PST - ppublish
SO  - Chemosphere. 2012 Jul;88(4):450-8. doi: 10.1016/j.chemosphere.2012.02.069. Epub 
      2012 Mar 19.