Age-related changes in grooming behavior and motor activity in female rats

The influence of hormonal status and the age of the rat on the expression o f grooming behavior and motor activity were studied. Grooming, locomotion, and rearing were measured in young (4-months-old), adult (6-8-months-old), and old (18-months-old) female rats, during the estrous cycle. These behavi oral performances were influenced by the hormonal changes that occur in you ng and adult female rats during the estrous cycle. In old rats there were n o significant differences among the different days of the estrous cycle. A significant age-related decrease in grooming behavior and motor activity wa s also found. Locomotion and rearing were the parameters most affected by a ge. These findings could be related to: (a) the gonadal hormonal status, wh ich appears to be able to modulate behavioral responses; and (b) the age-re lated changes, which may affect the normal display of these behaviors. The possible role of central peptidergic, cholinergic, and dopaminergic neural systems is discussed. (C) 1999 Elsevier Science Inc.