title: Cerebellar Purkinje cells fire paroxysmal depolarization shift (PDS)-like events in response to epileptogenic drugs.
abstract: OBJECTIVE
  Cerebellar Purkinje cells (PCs) fire burst of Na(+) spikes riding on a Ca(2+) spike which basically involves the same ionic channels and currents establishing the paroxysmal depolarization shift (PDS) discharges.
  
  
  METHODS
  Intracellular recordings were taken from somata of PCs to explore effects of the epileptogenic drugs of pentylenetetrazol (PTZ), bicuculline methiodide (BCC) and 4-aminopyridine (4-AP) on the firing behavior of these cells.
  
  
  RESULTS
  PCs showed spontaneous PDS-like events in presence of these drugs. Generally, PTZ and BCC-induced PDSs were similar in shape and properties but were remarkably different from 4-AP-induced PDSs. Blockade of glutamate transmission inhibited generation of PDSs by PTZ and BCC but it did not affect discharge of PDSs induced by 4-AP. Careful analysis of PDS discharges revealed that they have remarkable differences with normal and 4-AP-induced spontaneous activity.
  
  
  CONCLUSIONS
  Data presented here indicate that PDS discharges in PCs are induced either by the imbalance between excitatory and inhibitory synaptic transmission or by the suppression of 4-AP-sensitive currents.
authors.affiliation: Department of Physiology and Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Tehran, Iran. hhaghdoost@qums.ac.ir
authors.forename: H
authors.initials: H
authors.lastname: Haghdoost-Yazdi
authors.forename: F
authors.initials: F
authors.lastname: Rajaei
authors.forename: M
authors.initials: M
authors.lastname: Janahmadi
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D002531:Cerebellum / Q000187:drug effects* / Q000502:physiology; D003292:Convulsants / Q000494:pharmacology*; D008297:Male; D010433:Pentylenetetrazole / Q000494:pharmacology; D011689:Purkinje Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003292:Convulsants; C017069:bicuculline methiodide; D015761:4-Aminopyridine; D010433:Pentylenetetrazole; D001640:Bicuculline