Abstract

Neonicotinoids are pesticides that act as agonists of nicotinic receptors for acetylcholine in insects' central nervous system (CNS). Chronic exposure to neonicotinoids in humans is related to autism, memory loss, and finger tremor. In this article, we evaluate the effect of subchronic oral administration of two neonicotinoids in the same mixture: clothianidin and thiacloprid. Decreasing doses of both pesticides were administered to rats starting from the lethal dose 50 (LD50) reported by the manufacturer. Our results indicate that the administration of three doses of decreasing amounts of LD50 (5/10, 4/10, and 3/10 LD50) resulted in 100% death in all cases. Ten administration times of 2/10 LD50 of the mixture caused only 20% of death cases after twenty-seven days, which was determined as a subchronic administration scheme. The animals administered 2/10 LD50 showed behavioral alterations after the first and second administration. Electrographic studies showed abnormal discharge patterns in the CNS. 72 h after the tenth dose, learning and memory tests were performed in the Morris water maze. Our results revealed significant decreases in permanence at the quadrant and the number of crosses (P=0.0447, P=0.0193, respectively), which represent alterations in the short-term memory test, but there were no significant changes in a long-term memory test. Likewise, the brains of these animals showed tissue architecture loss, nucleosomal retraction, and a significant increase in the pycnosis of the granular neurons of the dentate gyrus analyzed at 72 h after the last dose (P=0.0125). Toxic effects and cognitive deterioration that have been found in communities living near contaminated areas are probably related to the agricultural use of neonicotinoids.

Highlights

  • IntroductionNeonicotinoids are the last generation of insecticides used in agriculture for the protection of crops against harmful insects. ese are derived from nicotine and are classified asN-nitroguanidines (clothianidin, imidacloprid, thiamethoxam, and dinotefuran) and N-cyano-aminides (thiacloprid and acetamiprid) [1]

  • Neonicotinoids are the last generation of insecticides used in agriculture for the protection of crops against harmful insects. ese are derived from nicotine and are classified asN-nitroguanidines and N-cyano-aminides [1]

  • In the present study, oral administration of the pesticide lethal dose 50 (LD50) resulted in 100% death in the animals

Read more

Summary

Introduction

Neonicotinoids are the last generation of insecticides used in agriculture for the protection of crops against harmful insects. ese are derived from nicotine and are classified asN-nitroguanidines (clothianidin, imidacloprid, thiamethoxam, and dinotefuran) and N-cyano-aminides (thiacloprid and acetamiprid) [1]. Neonicotinoids are the last generation of insecticides used in agriculture for the protection of crops against harmful insects. Neonicotinoids act as agonists of the nicotinic receptors for acetylcholine (nAChRs) in insects and mammals, especially on the subtype α4β2. In Mexico, these kinds of insecticides are used to treat seeds, soil, or leaves of crops such as cotton, chili, tomato, Journal of Toxicology potato, tobacco, corn, and apple, among others, including ornamental plants [2]. Mixtures of pesticides are currently used in agriculture to produce rapid destruction of pests or the economy of carrying out a single spraying operation [3]. It has been found that insecticide mixtures are related to neurotoxic effects [5, 6]. C. Peffer, “A critical review of neonicotinoid insecticides for developmental neurotoxicity,” Critical Reviews in Toxicology, vol 46, no. “A critical review of neonicotinoid insecticides for developmental neurotoxicity,” Critical Reviews in Toxicology, vol 46, no. 2, pp. 153–190, 2016

Objectives
Methods
Findings
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call