Acute Seizure Tests in Epilepsy Research: Electroshock‐ and Chemical‐Induced Convulsions in the Mouse

William J. Giardina1, Maciej Gasior2

1 Abbott Laboratories, Abbott Park, Illinois, 2 Cephalon, West Chester, Pennsylvania
Publication Name:  Current Protocols in Pharmacology
Unit Number:  Unit 5.22
DOI:  10.1002/0471141755.ph0522s45
Online Posting Date:  June, 2009
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Abstract

Epilepsy is a common (50 million patients worldwide) neurological disorder characterized by seizures that are caused by episodic abnormal electrical activity in the brain. Animal models play an essential role in epilepsy research including the discovery and development of new antiepileptic drugs. Described in this unit are protocols for traditional acute tests in which seizures are induced by either an electrical stimulation or a convulsant agent in non‐epileptic mice. Specifically, protocols for the following acute seizure tests are provided: the maximal electroshock induced test (MES), the maximal electroshock seizure threshold (MEST) test, the 6‐Hz seizure test, the subcutaneous pentylenetetrazol (s.c. PTZ) seizure test, and the intravenous pentylenetetrazol (i.v. PTZ) seizure test. These tests can be used to characterize anticonvulsant and/or proconvulsant properties of compounds in mice. The MES, s.c. PTZ, and 6‐Hz seizure tests represent the three most widely used animal tests in drug‐screening programs. Although the parameters of these tests are optimized for mice, the same tests (except for the 6‐Hz seizure test), with some modifications, can be used with rats. Curr. Protoc. Pharmacol. 45:5.22.1‐5.22.37. © 2009 by John Wiley & Sons, Inc.

Keywords: seizure; convulsion; MES; MEST; 6‐Hz; pentylenetetrazol; epilepsy; convulsant

     
 
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Table of Contents

  • Introduction
  • Basic Protocol 1: Anticonvulsant Determination in the Maximal Electroshock (MES) Test in the Mouse
  • Alternate Protocol 1: Anticonvulsant Determination in the Maximal Electroshock Seizure Threshold (MEST) Test Using the Method of Limits in the Mouse
  • Alternate Protocol 2: Anticonvulsant Determination in the Maximal Electroshock Seizure Threshold (MEST) Test Using the “Up‐and‐Down” Method in the Mouse
  • Basic Protocol 2: Anticonvulsant Determination in the 6‐Hz Seizure Test in the Mouse
  • Basic Protocol 3: Proconvulsant/Anticonvulsant Determination Using Pentylenetetrazol (120 mg/kg, Subcutaneous)‐Induced Clonic and Tonic Convulsions in the Mouse
  • Alternate Protocol 3: Anticonvulsant Determination Using Pentylenetetrazol (85 mg/kg s.c.)‐Induced Clonic Convulsions in the Mouse
  • Basic Protocol 4: Anticonvulsant Determination Using a Timed Intravenous Infusion of Pentylenetetrazol to Induce Convulsions in the Mouse
  • Basic Protocol 5: Anticonvulsant Determination Using Bicuculline, Picrotoxin, or Strychnine‐Induced Convulsions in the Mouse
  • Commentary
  • Literature Cited
  • Tables
     
 
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Materials

Basic Protocol 1: Anticonvulsant Determination in the Maximal Electroshock (MES) Test in the Mouse

  Materials
  • CD1 or NMRI male mice (Charles River Laboratories or Taconic Farms), 25 to 35 g, group housed on a 24‐hr diurnal cycle (lights on at 0700 and off at 1900), fed standard rodent diet
  • Vehicle: distilled water, saline, or 0.2% (w/v) hydroxypropylmethylcellulose (HPMC; see step 2)
  • Reference compound: e.g., carbamazepine (Sigma) in 0.2% (w/v) HPMC
  • Test compounds
  • Topical anesthetic: 0.5% tetracaine⋅HCl (J.A. Webster)
  • Electrode gel (Grass Telefactor, Astro‐Med)
  • Transparent plastic cages, 59‐cm × 39‐cm × 14‐cm, with bedding
  • Permanent‐ink black marker
  • Electroconvulsive shock apparatus with corneal stimulating electrodes (Hugo Sachs Rodent Shocker, Type‐221)
  • CO 2 gas chamber, made in‐house using a Nalgene Multipurpose Jar (13‐cm diameter, 19‐cm high) with a hole in the lid for a 0.5‐in diameter gas tube from a CO 2 gas cylinder equipped with a regulator valve

Alternate Protocol 1: Anticonvulsant Determination in the Maximal Electroshock Seizure Threshold (MEST) Test Using the Method of Limits in the Mouse

  • Reference compound(s): e.g., diazepam (Sigma) or RO 15‐4513 (Sigma) in 0.2% (w/v) HPMC
NOTE: Do not deliver currents greater than twice the intensity used in the MES test ( protocol 1) during this procedure in mice.

Alternate Protocol 2: Anticonvulsant Determination in the Maximal Electroshock Seizure Threshold (MEST) Test Using the “Up‐and‐Down” Method in the Mouse

  Materials
  • CD1 or NMRI male mice (Charles River Laboratories or Taconic Farms), 25 to 35 g, group housed on a 24‐hr diurnal cycle (lights on at 0700 and off at 1900), fed standard rodent diet
  • Vehicle: distilled water, saline, or 0.2% (w/v) hydroxypropylmethylcellulose (see step 2)
  • Reference compounds: e.g., diazepam (Sigma) and RO‐15‐4513 (Sigma) in 0.2% (w/v) HPMC
  • Pentylenetetrazol (PTZ; Sigma) in saline
  • Holding cage, transparent plastic, 59‐cm × 39‐cm × 14‐cm, with bedding
  • Permanent‐ink black marker
  • Individual observation cages, transparent plastic, 27‐cm × 21‐cm × 14‐cm, with bedding, one for each mouse in a testing group
  • Timers, one for each observation cage
  • CO 2 gas chamber

Basic Protocol 2: Anticonvulsant Determination in the 6‐Hz Seizure Test in the Mouse

  • Reference compounds: e.g., diazepam (Sigma), and valproic acid (Sigma) in 0.2% (w/v) HPMC

Basic Protocol 3: Proconvulsant/Anticonvulsant Determination Using Pentylenetetrazol (120 mg/kg, Subcutaneous)‐Induced Clonic and Tonic Convulsions in the Mouse

  Materials
  • CD1 or NMRI male mice (Charles River Laboratories or Taconic Farms), 25 to 30 g, group housed on a 24‐hr diurnal cycle (lights on at 0700 and off at 1900), fed standard rodent diet
  • Vehicle: distilled water, saline, or 0.2% (w/v) hydroxypropylmethylcellulose (HPMC; see step 2)
  • Reference compounds: e.g., diazepam, valproic acid, caffeine, and Ro‐15‐4513 (all from Sigma)
  • Pentylenetetrazol (PTZ) in sterile saline (Sigma)
  • Holding cages, transparent plastic, 59‐cm × 39‐cm × 14‐cm, with bedding
  • Permanent‐ink black markers
  • Tail access rodent restraint (Stoelting)
  • 27‐G needles connected to a polyethylene tubing (PE‐10)
  • Syringe pump (Stoelting or Harvard Apparatus, Pump 22, Model HA22I; or Kd Scientific)
  • CO 2 gas chamber

Alternate Protocol 3: Anticonvulsant Determination Using Pentylenetetrazol (85 mg/kg s.c.)‐Induced Clonic Convulsions in the Mouse

  • Bicuculline (BIC) or picrotoxin (PIC) or strychnine (STR) (all available from Sigma)
  • Reference compound: e.g., diazepam (Sigma) in 0.2% (w/v) HPMC (see step 2)
  • Individual observation cages, transparent plastic, 27‐cm × 21‐cm × 14‐cm, with bedding, one for each mouse in a testing group
  • Timers, one for each observation cage
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Literature Cited

Literature Cited
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