title: Rotenone causing dysfunctional mitochondria and lysosomes in cerebral ganglions of Lumbricus terrestris degenerate giant fibers and neuromuscular junctions.
abstract: Rotenone is well-documented to cause neurodegenerative condition such as Parkinson's, in the exposed systems. However, its detrimental effect on particular sites of neuronal pathway is still under investigation. We aimed at elucidating the impact of rotenone on cerebral ganglions (CG) of Lumbricus terrestris which control movement and behaviour of the worms. Worms were exposed to 0-0.4 ppm/mL of rotenone. Mitochondrial and lysosomal integrities were found to be affected beyond 0.2 ppm/mL of rotenone. Activities of cholinergic enzymes and the expression of tyrosine hydroxylase showed an impaired neuronal transmission in CGs at the dose of 0.2 ppm/mL of rotenone. Histopathological and immunoflourescent analyses showed neuronal apoptosis, reduced nucleic acid content and inhibited of neurosecretion at 0.3 ppm/mL. Electron microscopy showed that the neurons and neuromuscular junctions were affected at 0.2 ppm/mL. Dose-dependent changes were also observed in the motor function such as burrowing behaviours and locomotion. Conduction velocity (CV) and locomotion assessment showed that the CV of lateral giant fiber (LGF) was reduced while that of MGF remains unaffected at 0.2 ppm, the dose at which the burrowing behaviour was also not affected. LGF, cholinergic enzymes and tyrosine hydroxylase are primarily targeted by rotenone affecting locomotion at 0.2 ppm/mL while MGF, neuropile and the burrowing behaviour were affected at 0.3 ppm/mL. We demonstrate, in addition to dose-dependent effects, that the bioaccumulation factors range 0.28-0.32 ppm/μg of rotenone cause degenerative impact on giant fibers affecting neuronal behaviors/locomotion of worms. We also propose worms for studying mechanisms of neuronal pathology caused by chemicals prevailing in earth's atmosphere.
authors.affiliation: Department of Biochemistry, University of Madras, Guindy Campus, Chennai, 600 025, India.
authors.forename: Mamangam
authors.initials: M
authors.lastname: Subaraja
authors.affiliation: Department of Biochemistry, University of Madras, Guindy Campus, Chennai, 600 025, India. Electronic address: vanielango@gmail.com.
authors.forename: Arambakkam Janardhanam
authors.initials: AJ
authors.lastname: Vanisree
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D005260:Female; D005724:Ganglia / Q000187:drug effects* / Q000502:physiology; D008124:Locomotion / Q000187:drug effects; D008247:Lysosomes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D009469:Neuromuscular Junction / Q000187:drug effects / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D009498:Neurotoxins / Q000633:toxicity*; D009835:Oligochaeta / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D012402:Rotenone / Q000633:toxicity*; D009435:Synaptic Transmission / Q000187:drug effects; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D009498:Neurotoxins; D012402:Rotenone; D014446:Tyrosine 3-Monooxygenase
keywords: Cerebral ganglions; Giant fibres; Movement; Neuropile; Rotenone