VL02_Rat and Mouse Basics

Taxonomy Rat

Taxonomy Mouse

• Easy to keep and breed (inexpensive accommodation)

• Polyestrous and polygamous (breeds year round)

• Especially mice: easy to genetically manipulate (transgenic (KO, KI), humanized, etc.)

• High inbreeding tolerance (20 generations and more, 98-99% homogeneity)

• High comparability with humans (similar clinical pictures, genetically closely related)

• Well characterized (genome, biology, genetic background, etc.)

• Haben Bauchnabel aber keine Mandeln

• Labyrinthe helfen dabei die Intelligenz von Ratten zu erforschen

• Wirsamkeit uns Sicherheit von Medikamenten werden an Ratten geprüft

• Für alle menschlichen Gene, die Krankheiten verursachen können, gibt es ein entsprechendes Gen bei Ratten

• können 15m fallen ohne sich zu verletzten

• sind zahm und können gut lernen

  • werden für Versuche zu Verhaltensforschung und Prüfung von Neuropharmaka verwendet

• 80% of the human and the mice gene are identical

• are often involvd in basic researche

  • are used in 70% of all experimental procedures

• Mice can not vomit which is why they are extra susceptible to toxic food

• 
  

—> Heat death at ambient temperatures above 37°C

Harderian Gland:

• Horseshoe-shaped accessory lacrimal gland

• Reddish secretion rich in porphyrin and fatty acids

• In case of illness/stress: crusting around eye and nose

Vision:

• Poorly developed vision

• Large depth of field, but poor accuracy

• Predominantly rods in retina (light/dark)

• Dichromatic colour vision with two types of cones

  • Ultraviolet wavelengths around 359 nm

  • Long-wave cones Wavelengths 505–509 nm

Hearing:

• Well developed - Hearing range extends from 250 Hz - 80 kHz

  • Most sensitive range: 8–32 kHz

• Communication in the ultrasonic range

Smell:

• Very good sense of smell

• Used primarily for intraspecies communication and orientation

• Vomeronasal organ crucial for pheromone reactions

Touch:

• Vibrissae

• Scanning the environmen

Herz:

Lunge:

Sex determination:

• Anogenital distance

  • Large distance = male

  • Small distance = female

• Only female animals have teats!

• Testicles in adult males (can be pulled into the abdominal cavity!)

Reproduction Rat

• Polyestrous throughout the year, cycle lasts 4–5 days

• Spontaneous ovulation

• Mating takes place during the dark phase of the photoperiod

• Egg cells can still be fertilised 10–12 hours after ovulation

• Mating can be detected by the presence of a vaginal plug

• Reproductive performance influenced by external and internal factors

• Young animals = altric

Reproduction Mouse

• Polyestrous throughout the year, cycle lasts 4–5 days

  • Spontaneous ovulation

• Ovulation does not occur in every oestrus

• Mating takes place during the dark phase of the photoperiod

• Egg cells can still be fertilised 10–12 hours after ovulation

• Mating can be detected by the presence of a vaginal plug

• Postpartum oestrus is normal, but fertile mating is less common

• Reproductive performance is influenced by external and internal factors

• Young animals = altric

Rat

• Social animals

• In the wild: large groups, territorial behaviour towards other rat groups, construction of complex structures

• Most active at night

• Omnivorous diet, coprophagy

• Laboratory rats bred for tameness

• Stress: alarm calls in the range of 22 kHz

• Adolescence: playful interactions with conspecifics

  —> Important for the development of species-appropriate social and sexual behaviour

Mouse

• Social animals

• In the wild: large groups of related animals

• high degree of natural inbreeding

• Crepuscular and nocturnal

• Omnivorous diet, coprophagy

• Strong territorial behavio

Movements are used for cleaning and temperature regulation

• Hand cleaning– face washing– body cleaning– limb cleaning–

  tail cleaning

• Grooming: (mutual) cleaning

• Barbering: excessive grooming with hair loss

• Whisker eating: gnawing on the vibrissae

  
  

• Missing fur (especially in BL/6 mice) does not necessarily indicate illness

Diet selection, eating, food hoarding

• Omnivore

• Coprophagy physiological

• Food intake in the form of meals

• Food is held and gnawed

• Eating and drinking behaviour linked

—> Animals that do not eat do not drink, and vice versa

—> dangerous metabolic situations

• Generally neophobic

• Unprotected areas are generally avoided

• Exploration is cautious, along physical structures

• Between individual explorations, return to already known, safe places

• Orientation based on visual landmarks and olfactory stimuli