Two-way shuttlebox avoidance conditioning in three DAB rat stocks.

Avoidance conditioning in FH rats, characterized by a peripheral serotonin deficiency, was compared with that in two stocks presumed to be their ancestors, Long-Evans (LE) and Wistars (W). Escapes, conditional avoidance response (CAR), and activity (locomotion) of the animals were studied in a two-way shuttlebox. FH females made fewer escapes and more CAR's, and were more active than both LE and W females. The behavioral differences among the males of the three stocks were not statistically significant. A CNS serotonin deficiency may be involved in the conditioning and activity differences among the females of the three stocks. Possible variation between sexes should be considered in investigating levels of CNS serotonin in FH rats, as well as other stocks.