Shuttle-Avoidance Learning of Mice: Effects of Post-Trial Pentylenetetrazol, Strain, and Age

Abstract

C57BL/6J and DBA/2J mice of two different ages (2 to 3 mo. vs 11 to 14 mo.) were given 20 trials per day for 6 days in a shuttle-avoidance task. Pentylenetetrazol (5, 10, or 20 mg/kg) or saline was given intraperitoneally immediately after Trial 20 on Days 1 to 5. The results showed a marked strain difference with DBA/2J mice superior to C57BL/6J mice. The effects of age on avoidance depended on both strain and sex. There was no effect of pentylenetetrazol in facilitating avoidance learning. A second experiment examined shuttle-avoidance learning in C57BL/6J and DBA/2J mice of three age groups: adult (2 to 4 mo.), aged (6 to 8 mo.), and senile (18 to 22 mo.). Over-all, DBA/2J mice performed better than C57BL/6J mice. There was no deterioration in avoidance learning with increased age.