Amphetamine-induced stereotypic responses in Roman high- and Roman low-avoidance rats.

The effects of 0, 1, 3 and 5 mg/kg d, 1-amphetamine (AMPH) on male RHA/Verh and RLA/Verh rats were measured, at 25 and 55 min post-injection, using an observational method in which six categories of behavior were scored. RHA/Verh rats displayed a more rapid increase of AMPH-induced stereotyped behavior, mostly due to drug-related differences in scanning (head-bobbing), whereas the differences in rearing seen (RHA/Verh greater than RLA/Verh) were attributable to purely genetic effects. These results were compared with those of previous experiments which measured apomorphine-induced stereotyped behavior in these, and other, Roman lines. It was concluded that the RHA/Verh rats probably showed a stronger response to AMPH due to their higher, and more drug-responsive, striatal dopamine turnover rate.