[Changes in the ultrastructure of the motor zone of the cortex and various areas of the rats pyramidal system in acute toxic action of phenazepam].
As it was revealed by electron microscopic study, phenazepam (benzodiazepine representative) administered to rats in acute toxic dose caused astrocyte processes swelling mainly in reticular portion of substantia nigra and cerebral areas with high density of GABAergic synapses in initial intoxication stage (one hour after the drug introduction). Following 24 hrs changes of axodendritic and axo-somatic synapse postsynaptic part were detected similar to those of myoneural synapses induced by anti-cholinesterase agents, which allows to suggest the contribution of the increased intracellular calcium ions content. Specific benzodiazepine receptor agonist-flumazenil, introduced 30 min later than phenazepam leaded to the decrease of ultrastructural changes in postsynaptic part of the synapses in reticular zone of substantia nigra. Thus toxic effect of drugs that cause prolonged activity of peripheral and central synapses postsynaptic part results in the alike ultrastructural changes irrespective of their mediator type and is likely to be connected with the growth of intracellular calcium concentration.
Tomilin
N V
NV
Institute of Toxicology, Russian Ministry of Public Health, St. Petersburg.
Cherniak
T F
TF
D000818:Animals; D014151:Anti-Anxiety Agents / Q000633:toxicity*; D001253:Astrocytes / Q000187:drug effects; D001569:Benzodiazepines; D001570:Benzodiazepinones / Q000633:toxicity*; D005116:Extrapyramidal Tracts / Q000187:drug effects* / Q000648:ultrastructure; D009044:Motor Cortex / Q000187:drug effects* / Q000648:ultrastructure; D051381:Rats; D013378:Substantia Nigra / Q000187:drug effects; D013569:Synapses / Q000187:drug effects; D013997:Time Factors
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D001569:Benzodiazepines; C017928:phenazepam
Izmeneniia ul'trastruktury dvigatel'noĭ zony kory i nekotorykh otdelov ékstrapiramidnoĭ sistemy krys pri ostrom toksicheskom deĭstvii fenazepama.