Rats

1. Acceptable
• Sodium pentobarbital
• 150 mg/kg IP
• Controlled substance
• Halothane/Isoflurane
• To effect
• High Concentration
• Rapid flow
  • High flow rates may initially frighten the animal
• If a chamber is used
• Animal should not come into contact with liquid
• Animals should not be overcrowded
• Animals should be compatible
• No breathing, no heart beat/pulse, no response to toe/ear pinch for at least 2 minutes
• Animal's activity should slow down, then stop, may or may not fall over
• If ventilation compromised, slow, requires prolong time
• Neonates tolerate hypoxia too well to use this method
• Requires a hood/ventilation
• Toxic to personnel
• Pregnant persons should avoid
• Should be less than 2 ppm in room
• Equipment has to be maintained
• Should be cleaned after each use to ensure no odors left
• Precision vaporizers need to be serviced annually
• Machines checked for leaks
• Requires some other method of euthanasia to ensure death such as removal of vital organ, exsanguination, or open chest
• CO2, CO
  • Gradual filling of tank is preferable
• A lower concentration (30%) is less distressful for animals
• In some species, higher concentrations failed to cause death
• To effect
  • No breathing, no heart beat/pulse, no response to toe/ear pinch for at least 2 minutes
  • Animal's activity should slow down, then stop, may or may not fall over
• Requires some other method of euthanasia to ensure death such as removal of vital organ, exsanguination, or open chest
• Must use a gas cylinder
• CO
• Very hazardous
• Special hazard training
• Must have monitors for CO in room for CO in room
• No residue
  • Does not distort murine cholinergic markers or corticosterone concentrations
  • May cause acidosis
• Microwave irradiation
  • Requires special, expensive equipment
2. Conditionally Acceptable
   • N2
     • Has to achieve <2% oxygen rapidly
     • If anesthetized, takes longer
   • Ar
     • Has to achieve <2% oxygen rapidly
     • If anesthetized, takes longer
   • Cervical dislocation
     • Less 200 grams
     • Requires scientific justification by user and approval of IACUC
     • Requires special training and monitoring
   • Decapitation
     • Requires scientific justification by user and approval of IACUC
     • Requires special training and monitoring
     • Hazard, requires special training for hazard
     • Equipment has to be maintained
     • Records have to be maintained of sharpening
3. Adjunctive methods
   • Methods that are acceptable when used in conjunction with another method that renders the animal unconscious first, prior to using the adjunctive method
   • Potassium chloride
   • Requires general anesthesia
   • 1-2 mmol/kg
   • Given IV or Intracardiac                                                                        Rat laying on its back
   • No withdrawal period
   • Get a rippling of muscles and clonic spasms
   • Exsanguination
   • Requires sedated, stunned, or generally anesthetized animal
4. Unacceptable
   • Intracardiac injection without general anesthesia
   • Chloral hydrate

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