TITLE:
Nervous System and Gastrointestinal Effects of the Insecticide Esfenvalerate on the Rat: An Ex Vivo Study
AUTHORS:
Petra Varró, Eszter Szabó, Melinda Kovács, Ildikó Világi
KEYWORDS:
Pyrethroid; Ileum Motility; Brain Slice; Field Potentials
JOURNAL NAME:
Agricultural Sciences,
Vol.5 No.4,
March
26,
2014
ABSTRACT: Esfenvalerate belongs to the
pyrethroid group of insecticides which display significant selective toxicity
against insects compared to mammalian species, nevertheless, they may pose health risks, especially in case of accidental
exposure. The aim of the present study was to model the effect of acute,
relatively high-dose exposure of the esfenvalerate-containing formulation
Sumi-Alpha?. Eventual functional alterations in the central nervous
system and in the gastrointestinal tract were studied on in vitro tissue preparations at different delays after intragastric administration to
rats. Neuronal effects were characterized by field potential recording in
cortical and hippocampal brain slices, while gastrointestinal effects were
examined by analyzing the motility and excitability
of isolated ileum segments. On the brain slices originating from
esfenvalerate-treated animals, changes in excitability of both inhibitory and
excitatory type could be observed. Voltage thresholds
necessary to evoke responses in neocortex slices were elevated, and population spike amplitudes
were lower in hippocampal slices. However, epileptiform potentials with
pronounced late components were also observed. A decreased long-term
potentiation (LTP) could be seen in both brain areas after esfenvalerate
treatment. Seizure susceptibility of the slices was not significantly altered, but tended to be somewhat higher in slices originating from treated rats. In
ileum segments, both spontaneous and acetyl-choline (ACh)-elicited contractions
were modified by treatment. Esfenvalerate raised the amplitude of contractions
in the low ACh concentration range. However, the solvent xylene also
considerably contributed to the detected changes. We can conclude that a
relatively high, single oral dose of Sumi-Alpha? exerted mild and
temporary effects on the elementary brain functions and intestine functions of
the rat.