title: Magnesium Effects on Nonsynaptic Epileptiform Activity in Leech Retzius Neurons.
abstract: The effects of Mg2+ on Ni(2+)-induced epileptiform bursting activity and input membrane resistance during this activity of leech Retzius neurons were examined using intracellular recordings. To induce epileptiform activity, 3 mmol/l NiCl2 was added into superfusing Ringer (Ri) saline. To test for dose-dependence of the effects of Mg2+ on the induced epileptiform activity, MgCl2 was added in concentrations from 1 mmol/l to 20 mmol/l Mg2+ to the Ni(2+)-containing Ri saline. Input membrane resistance (IMR) was measured in standard Ri, Ni2+ Ri and 20 mmol/l Mg2+Ni2+ Ri saline. Superfusion with Ni2+ Ri induced epileptiform bursting activity characterized by generation of paroxysmal depolarization shifts (PDSs). Parameters of epileptiform activity including PDS frequency, PDS duration, PDS amplitude and the number of spikes/PDS were measured. Magnesium suppressed Ni(2+)-induced epileptiform activity, significantly reducing values of all parameters observed in a concentration-dependent manner. The highest concentration applied of 20 mmol/l Mg2+ completely eliminated epileptiform activity. To test for the effect of Mg2+ on membrane conductance during bursting, IMR was measured. Magnesium significantly increased IMR during bursting suppression.
authors.forename: Marija
authors.initials: M
authors.lastname: Stanojević
authors.forename: Srdjan
authors.initials: S
authors.lastname: Lopicic
authors.forename: Zorica
authors.initials: Z
authors.lastname: Jovanovic
authors.forename: Dhruba
authors.initials: D
authors.lastname: Pathak
authors.forename: Dragan V
authors.initials: DV
authors.lastname: Pavlovic
authors.forename: Svetolik
authors.initials: S
authors.lastname: Spasic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Nedeljkov
authors.forename: Milica
authors.initials: M
authors.lastname: Prostran
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D007865:Leeches / Q000166:cytology*; D008274:Magnesium / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D009532:Nickel / Q000494:pharmacology
chemical_list: D009532:Nickel; D008274:Magnesium