Journal of Applied Physiology, Vol 78, Issue 4 1219-1224, Copyright © 1995 by American Physiological Society
Daily spontaneous running alters behavioral and neurochemical indexes of nigrostriatal function
D. E. Dluzen, B. Liu, C. Y. Chen and S. E. DiCarlo
Department of Anatomy, Northeastern Ohio Universities, College of Medicine, Rootstown 44272-0095, USA.
Behavioral and neurochemical indexes of nigrostriatal dopaminergic function
were compared between sedentary control rats (n = 12) and daily spontaneous
running (DSR) male rats (n = 10). Nine weeks of DSR did not significantly
alter body, heart, pituitary, or testes weights. DSR and control animals
did differ in performance on a sensorimotor beam walking task, with DSR
rats showing significantly shorter times required to cross the beam (60 +/-
17 vs. 119 +/- 14s; P < 0.02) as well as fewer slips off the beam (3.0
+/- 0.8 vs 6.2 +/- 1.1; P < 0.05). DSR animals also engaged in
significantly greater durations of social investigation than control rats
(43 +/- 5 vs 25 +/- 3 s; P < 0.01) when tested in a social investigation
memory-recognition test. Basal dopamine release rates from superfused
corpus striatal tissue fragments of DSR rats were about one-half those
obtained from control animals (18 +/- 5 vs. 34 +/- 6 pg.mg-1.min-1; P <
0.05), whereas responses of these striatal tissue fragments to a
depolarizing concentration of potassium were virtually identical (45 +/- 10
vs. 47 +/- 8 pg.mg-1.min-1). These data indicate that a relatively limited
intensity of DSR insufficient to alter cardiovascular function can exert
substantial effects on behavioral and neurochemical indicators of
nigrostriatal dopaminergic activity.
