Effects of locally applied dopamine to the nucleus accumbens on the motor activity of normal rats and following alpha-methyltyrosine or reserpine.
The motor activity of rats was investigated following bilateral application of various doses (0--80 micrograms) of dopamine to the nucleus accumbens. A high dose (80 micrograms) of dopamine increased the motor activity of normal as well as alpha-methyltyrosine- and reserpine-treated rats. It also increased the late motor activity (6--9 min) of normal rats, probably due to stimulation of postsynaptic dopamine receptors. Lower doses (10--40 micrograms) of dopamine suppressed initial (0--3 min) motor activity of normal rats, perhaps due to stimulation of dopamine autoreceptors on the dopamine nerve terminals in the nucleus accumbens with a subsequent inhibition of dopamine neurotransmission. An intermediate dose (40 micrograms) of dopamine was able to restore the motor activity of alpha-methyltyrosine-treated but not of reserpine-treated rats at all time intervals. This difference, indicating a restoration of the normal pattern of habituation by dopamine only in animals pretreated with alpha-methyltyrosine, suggests that normal behaviour is dependent on release of dopamine by nerve impulses.
D000818:Animals; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D007267:Injections; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000502:physiology*; D051381:Rats; D012110:Reserpine / Q000494:pharmacology*; D012686:Septal Nuclei / Q000502:physiology*; D013997:Time Factors
D008781:Methyltyrosines; D012110:Reserpine; D004298:Dopamine