5-HT loss in rat brain by type II pyrethroid insecticides

Abstract

A serotonin depleting effect was produced by these type II pyrethroids. The concentration of 5-HT and its metabolite 5-HIAA decreased in the brain regions from pyrethroid treated animals. Pyrethroids accelerated the turnover of 5-HT in midbrain and striatum areas. It is concluded that pyrethroids affect serotonin neurotransmission.

Effects of exposure to pyrethroid cyfluthrin on serotonin and dopamine levels in brain regions of male rats

“…Moreover, other effects have been involved such as effects on voltage sensitive calcium channels, voltage sensitive chloride channels, GABA A receptors and on the release of neurotransmitters (Narahashi, 1996;Martínez-Larrañaga et al, 2003;Hossain et al, 2004;Shafer et al, 2005;Ray and Fry, 2006;Brown et al, 2006;Nasuti et al, 2007;Breckenridge et al, 2009). In the present study, we showed that the pyrethroid cyfluthrin produced in a dose-dependent manner a statistically significant decrease of the 5-HT levels in all brain regions studied (hypothalamus, striatum, midbrain, hippocampus and prefrontal cortex).…”

“…Following sample collections, 300-800 ml of 0.4 M HClO 4 containing 0.1% (w/v) Na 2 S 2 O 5 was added to the tissues, and the mixture was homogenized (1 min) by sonication (Labsonic U-Braun) before neurochemical evaluation was performed. The homogenates were centrifuged (RC5C, Sorvall Instruments) at 12,000g for 20 min at 4 ºC and aliquots of supernatants were taken for analysis of dopamine (DA) and its metabolites [3,4-hydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)] and serotonin (5-HT) and its metabolite [5-hydroxy-3-indolacetic acid (5-HIAA)] using a high performance liquid chromatography (HPLC) technique with electrochemical detection (Colado et al, 1993) with modifications (Martínez-Larrañaga et al, 2003).…”

“…Once absorbed, pyrethroid gives rise within minutes nausea, vomiting, abdominal pain; systemic effects occur from 4 to 48 h after exposure such as dizziness, headache, fatigue, blurred vision, coma, and convulsions (Bradberry et al, 2005;Ray and Fry, 2006). In rodents, it is known that early exposure to pyrethroids can lead to permanent changes in cholinergic and behavioral variables (Eriksson and Fredriksson, 1991), as well as they may specifically target the dopaminergic and serotoninergic systems (Karen et al, 2001;Bloomquist et al, 2002;Martínez-Larrañaga et al, 2003;Gillette and Bloomquist, 2003;Elwan et al, 2006), which may be a contributory factor in the etiology of human neurodegenerative disorders such as of Parkinson's disease, disorder characterized by the loss of nigrostriatal dopamine neurons (Olanow and Tatton, 1999). Several epidemiological studies have identified pesticide exposure as a significant risk factor for neurodegenerative diseases (Gorell et al, 1998;Priyadarshi et al, 2001).…”

Evidence for dose-additive effects of a type II pyrethroid mixture. In vitro assessment

“…The long-term effects of pyrethroid exposure are not clear. The most commonly examined effects in epidemiological and animal studies include neurotoxicity, neurobehavioral and neurodevelopment effects as well as endocrine disrupting effects (Martínez-Larrañaga et al, 2003;Shafer et al, 2005;Mckinlay et al, 2008;Wolansky and Harrill, 2008).…”

The pesticide deltamethrin increases free radical production and promotes nuclear translocation of the stress response transcription factor Nrf2 in rat brain

“…In addition, DM caused neuronal apoptosis, accompanied by increased expression of proapoptotic p53 and Bax, and decreased expression of antiapoptotic Bcl-2 (Wu et al, 2000;Wu and Liu, 2000a, b). Deltamethrin also selectively increased dopamine release and uptake in the dopaminergic nerve terminals of the striatum, and even altered serotonergic neurotransmission (Kirby et al, 1999;Martinez-Larrañaga et al, 2003). Environmental or occupational exposure to pyrethroid pesticides, therefore, may produce specific damage to dopaminergic neurons, but the full extent of DM-induced neuropathology is still unknown.…”