vision/eye phenotype

• abnormal vision
  • optokinetic tracking indicates a decrease in contrast sensitivity over multiple spatial frequencies
  (MGI Ref ID J:185955)

• abnormal eye electrophysiology
  • overall light-adapted electroretinographic response is significantly reduced
  (MGI Ref ID J:185955)
  • on day 2 in constant darkness, circadian regulation of the light-adapted electroretinographic response is abolished
  (MGI Ref ID J:185955)

homeostasis/metabolism phenotype

• increased dopamine level
  • following DOPA decarboxylase inhibition, homozygotes accumulate more L-DOPA in the dorsal striatum-caudate putamen (CPU) relative to wild-type mice
  (MGI Ref ID J:43061)
  • homozygotes exhibit elevated dopamine synthesis and its conversion to DOPAC in the dorsal striatum, as shown by a 93% increase of DOPAC content in CPU and a 1.9-fold increase in DOPAC/DA ratio relative to wild-type mice
  (MGI Ref ID J:43061)

mammalian phenotype

• behavior/neurological phenotype
  • Normal - amphetamine-treated mice exhibit normal reductions in prepulse inhibition and startle reactivity
  (MGI Ref ID J:55027)

• nervous system phenotype
  • Normal - amphetamine-treated mice exhibit normal reductions in prepulse inhibition and startle reactivity
  (MGI Ref ID J:55027)

behavior/neurological phenotype

• decreased vertical activity
  • homozygotes exhibit fewer rearing episodes in an open field environment relative to wild-type mice
  (MGI Ref ID J:43061)

• decreased exploration in new environment
  • in the novel object test, homozygotes exhibit a smaller increase in % of time spent in the center after introduction of the cup relative to wild-type mice
  (MGI Ref ID J:76023)
  • in the open field test, homozygotes make fewer entries into the center, but do not differ in overall levels of activity relative to wild-type mice
  (MGI Ref ID J:76023)
  • overall, homozygotes display the largest reductions in behavioral responses to novelty in the test that maximizes approach behaviors (novel object test), and the smallest reductions in the test that maximizes avoidance behavior (open field test)
  (MGI Ref ID J:76023)
  • in the emergence test, homozygotes spend more time in the cylinder and make fewer entries into the cylinder relative to wild-type mice
  (MGI Ref ID J:76023)

• hypoactivity
  • female homozygotes appear to be slightly more active than males
  (MGI Ref ID J:43061)
  • homozygotes cover less horizontal distance, initiate fewer movements and spend less time in motion in an open field environment relative to wild-type mice
  (MGI Ref ID J:43061)

• impaired behavioral response to addictive substance
  • however, both genotypes of mice exhibit completely loss of apomorphine-induced locomotion in response to 6 mg/kg clozapine
  (MGI Ref ID J:43061)
  • Normal - however, both genotypes of mice exhibit complete loss of apomorphine-induced locomotion in response to 6 mg/kg clozapine
  (MGI Ref ID J:43061)
  • unlike wild-type, catecholamine-depleted, akinetic-rendered homozygotes fail to exhibit a 40% suppression of apomorphine-induced locomotor activity in response to 0.6 mg/kg clozapine
  (MGI Ref ID J:43061)

• hyperactivity elicited by ethanol administration
  • homozygotes are supersensitive to the locomotor-stimulating effects of ethanol (20% v/v) relative wild-type mice
  (MGI Ref ID J:43061)

• enhanced behavioral response to cocaine
  • homozygotes display a dose-dependent hypersensitivity to the locomotor-stimulating effects of cocaine and methamphetamine
  (MGI Ref ID J:43061)

• enhanced coordination
  • homozygotes outperform their wild-type littermates on the rotarod, with 50% fewer falls and a 2.5-fold increase in the length of time remaining on the rotarod
  (MGI Ref ID J:43061)