Voluntary running distance is negatively correlated with striatal dopamine release in untrained rats.
This study examined the relationship between voluntary running distance and glutamate- and K+-stimulated dopamine release in the striatum (nucleus accumbens and caudate-putamen) of male Long-Evans rats. Twenty-one rats were housed individually in cages with attached running-wheels for 1 week. There was a 19-fold variability between rats in voluntary running distances over this period (range = 2.3-44.6 km). The average distance completed during the week was 16 +/- 2.8 km. There was a strong positive correlation between the running distances completed during the first 24 h (day 1) and the last 24 h. Certain rats were therefore inclined to run from the start. The average daily running distance (2.4 +/- 0.4 km per day) was negatively correlated with the weight of the rat (r = -0.82). Glutamate-stimulated release of dopamine was not a significant predictor of voluntary running distance. However, the average daily running distance was negatively correlated with K+-stimulated dopamine release in the nucleus accumbens core and caudate-putamen but not the nucleus accumbens shell. The present findings suggest that decreased depolarization-induced release of striatal dopamine may be a predictor of hyperactivity. The results show, in a normal population of Long-Evans rats, that there are, at the end of the continuum, rats that display some of the neurochemical and behavioral characteristics of a rat model for attention-deficit hyperactivity disorder.
Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa.
Bernard A
BA
Tarr
Lauriston A
LA
Kellaway
Alan
A
St Clair Gibson
Vivienne A
VA
Russell
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D018698:Glutamic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D012420:Running / Q000502:physiology*; D014316:Tritium / Q000378:metabolism
D014316:Tritium; D018698:Glutamic Acid; D011189:Potassium Chloride; D004298:Dopamine