Cypermethrin induced: In vivo inhibition of the acetylcholinesterase activity in functionally different tissues of the freshwater teleost, Labeo rohita (Hamilton)
ABSTRACT Effects of cypermethrin at different concentrations and exposure periods were investigated on the freshwater fish, Labeo rohita, to establish inhibitory effect of pesticide on acetyl cholinesterase (AChE) activity and associated behavioral changes. Fish were exposed to 1/7th (0.57 µg L-1) and 1/12th (0.33 µg L-1) of the lethal concentration (4 µg L-1) of cypermethrin for a period of 1, 7, or 14 days and allowed to recover for a further 7 days. Maximal inhibition in AChE activity in exposed fish was found in brain followed by muscle, gill, and liver on day 14 at both sublethal concentrations of cypermethrin. Recovery showed a rise in AChE activity but significantly decreased compared to controls. Depression of AChE activity suggests decreased cholinergic transmission and consequent accumulation of acetylcholine (ACh) in tissues leading to cessation of nerve impulses. This led to behavioral and morphological changes due to impaired neurophysiology in fish. Fish in toxic media exhibited erratic, and darting swimming movements, hyperexcitability, and loss of equilibrium and these symptoms persisted even during recovery.
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ABSTRACT: Liver is removed from albino rat and assayed for total adenosine triphosphatase (ATPase) activity following administration with single and repeated doses of larvin and cypermethrin. The data indicate that the total (Na+, K+; Mg2+) dependent ATPase in the liver tissue is significantly inhibited by single and repeated doses of both insecticides. This inhibition is more pronounced by the repeated dose of cypermethrin than that of larvin. The in vitro study revealed that the inhibition encountered by different concentration of both larvin and cypermethrin is of the irreversible non-competitive type. This data indicate that these insecticides can cause biochemical and histopathological changes in the liver ATPase activity which may inhibit several biochemical functions of ATPase system such as: the active transport of metal ions, oxidative phosphorylation of liver cells and generally the muscle contraction.Journal of Environmental Science and Health Part B 11/1993; 28(5):599-619. · 1.21 Impact Factor
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ABSTRACT: Neuroexcitatory symptoms of acute poisoning of vertebrates by pyrethroids are related to the ability of these insecticides to modify electrical activity in various parts of the nervous system. Repetitive nerve activity, particularly in the sensory nervous system, membrane depolarization, and enhanced neurotransmitter release, eventually followed by block of excitation, result from a prolongation of the sodium current during membrane excitation. This effect is caused by a stereoselective and structure-related interaction with voltage-dependent sodium channels, the primary target site of the pyrethroids. Near-lethal doses of pyrethroids cause sparse axonal damage that is reversed in surviving animals. After prolonged exposure to lower doses of pyrethroids axonal damage is not observed. Occupational exposure to pyrethroids frequently leads to paresthesia and respiratory irritation, which are probably due to repetitive firing of sensory nerve endings. Massive exposure may lead to severe human poisoning symptoms, which are generally treated well by symptomatic and supportive measures.Critical Reviews in Toxicology 02/1990; 21(2):105-26. · 6.25 Impact Factor
Article: Probit Analysis