title: Acute effects of pyrethroids on serotonin release in the striatum of awake rats: an in vivo microdialysis study.
abstract: The present study examined the acute neurotoxic effects of three different pyrethroids, allethrin, cyhalothrin, and deltamethrin on the release of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the striatum of conscious rats using microdialysis. Allethrin 10 mg/kg reduced extracellular levels of 5-HT to 46%, whereas 20 and 60 mg/kg increased the release to 177% and 243% of baseline, respectively. Cyhalothrin increased 5-HT release to 145-204% and deltamethrin decreased to 58-32% of baseline in a dose-dependent manner. None of the pyrethroids tested altered extracellular levels of 5-HIAA. Local infusion of the voltage-gated sodium channel antagonist tetrodotoxin (TTX) into striatum completely prevented the effects of allethrin, cyhalothrin, and deltamethrin (10 and 20 mg/kg) on 5-HT release. The effect of deltamethrin at 60 mg/kg was completely abolished by striatal infusion of nimodipine (L-type Ca⁺⁺ channel antagonist) with TTX. These findings suggest that pyrethroids disrupt the serotonergic neurotransmission in striatum in a dose-related manner with Na⁺ and Ca²⁺ channel-dependent mechanisms.
authors.affiliation: Department of Environmental and Occupational Medicine and Environmental and Occupational Health Sciences Institute, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA. mhossain@eohsi.rutgers.edu
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Hossain
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Suzuki
authors.forename: Jason R
authors.initials: JR
authors.lastname: Richardson
authors.forename: Haruo
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D017551:Microdialysis; D011722:Pyrethrins / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014851:Wakefulness / Q000187:drug effects*
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D026941:Sodium Channel Blockers; D012701:Serotonin; D013779:Tetrodotoxin