Open-field behavior of prenatally irradiated and/or postnatally handled C57BL/6 mice

Mice (C57BL/6) were prenatally irradiated with 60Co and/or handled on postnatal Days 1-10, and subsequently tested in an open field on Days 21, 42, and 63, and in a shuttle box on Days 30 and 60. Another group of mice was treated and tested similarly, but the shuttle box testing was omitted. All animals were cross-fostered at birth. Handling increased open-field activity and decreased defecation whereas irradiation decreased activity and had inconsistent effects on defecation. A comparison of the data from both groups of mice indicated that the shuttle box experience decreased open-field activity, particularly for the irradiated and unhandled animals. Direct and indirect irradiation effects--revealed by the cross-fostering procedure--were both significant and about equal in magnitude, underlining the importance of attending to irradiation effects on maternal as well as on offspring behavior.