title: Opposite effects of moderate heat stress and hyperthermia on cholinergic system of soil nematodes Caenorhabditis elegans and Caenorhabditis briggsae.
abstract: Cholinergic system plays important role in all functions of organisms of free-living soil nematodes C. elegans and C. briggsae. Using pharmacological analysis we showed the existence of two opposite responses of nematodes cholinergic system to moderate and extreme heat stress. Short-term (15min) noxious heat (31-32°C) caused activation of cholinergic synaptic transmission in C. elegans and C. briggsae organisms by sensitization of nicotinic ACh receptors. In contrast, hyperthermia blocked cholinergic synaptic transmission by inhibition of ACh secretion by neurons. The resistance of behavior to extreme high temperature (36-37°C) was significantly higher in C. briggsae than in C. elegans, and thermostability of cholinergic transmission correlated with resistance of behavior to hyperthermia. Activation of cholinergic transmission by moderate heat stress can be the reason of movement speed increase in such adaptive behavior as noxious heat escape. Inhibition of ACh release is one of reasons for behavior failure caused by extreme high temperature since partial inhibition of ACh-esterase by aldicarb protected C. elegans and C. briggsae behavior against hyperthermia. Antagonist of mAChRs atropine almost completely prevented the rise in behavior thermotolerance caused by aldicarb. Pilocarpine, agonist of mAChRs, protected nematodes behavior against hyperthermia similarly with aldicarb. Therefore it is evident that it is the deficiency of mAChRs activity that is the reason for nematodes' behavior failure by hyperthermia.
authors.affiliation: Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia. Electronic address: tbkalinnikova@gmail.com.
authors.forename: Tatiana B
authors.initials: TB
authors.lastname: Kalinnikova
authors.affiliation: Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia.
authors.forename: Rufina R
authors.initials: RR
authors.lastname: Kolsanova
authors.affiliation: Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia.
authors.forename: Evgenia B
authors.initials: EB
authors.lastname: Belova
authors.affiliation: Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia.
authors.forename: Rifgat R
authors.initials: RR
authors.lastname: Shagidullin
authors.affiliation: Research Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences, Daurskaya str., 28, 420087 Kazan, Russia.
authors.forename: Marat Kh
authors.initials: MK
authors.lastname: Gainutdinov
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000448:Aldicarb / Q000008:administration & dosage; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002107:Caenorhabditis / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000502:physiology; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage; D005334:Fever / Q000503:physiopathology*; D018869:Heat-Shock Response; D007978:Levamisole / Q000008:administration & dosage; D009538:Nicotine / Q000008:administration & dosage; D018722:Nicotinic Agonists / Q000008:administration & dosage; D011978:Receptors, Nicotinic / Q000502:physiology*; D013550:Swimming; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D002800:Cholinesterase Inhibitors; D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; D007978:Levamisole; D009538:Nicotine; D000448:Aldicarb; D000109:Acetylcholine
keywords: Cholinergic system; Hyperthermia; Muscarinic ACh receptors; Nematodes; Nicotinic ACh receptors; Noxious heat