Residential-maze behavior of spontaneously hypertensive rats

Spontaneously hypertensive rats (SHR) exhibit elevated levels of ambulation after transfer to a novel environment compared to the Wistar-Kyoto rat (NR). The present experiment compared long-term activity of SHR and NR in a residential maze to determine whether the SHR exhibit elevated levels of locomotor activity under undisturbed, baseline conditions in addition to enhanced reactivity to stimuli. The SHR were much more active visiting more arms of the maze than the NR during the initial hours following transfer to the maze, and during hours around dark onset and light onset. However, the SHR also exhibited higher levels of activity than the NR under baseline conditions. While the NR visited the arm containing food more frequently than other arms, the SHR exhibited no such preference. These data show that both stimulus-induced and basal levels of ambulation are increased in the SHR compared to its normotensive genetical counterpart.