Journal of Neuroscience, Vol 1, 292-299, Copyright © 1981 by Society for Neuroscience
Neuronal responses of the globus pallidus to systemic administration of d-amphetamine: investigation of the involvement of dopamine, norepinephrine, and serotonin
DA Bergstrom and JR Walters
Systemic administration of d-amphetamine (d-AMP) caused significant
increases in the unit activity of spontaneously firing neurons in the rat
globus pallidus. Intravenous injection of 0.2 mg/kg of d-AMP produced an
average increase of 32% while a cumulative dose of 6.4 mg/kg of d-AMP
increased cell firing 81% above base line control. The excitatory effects
of d-AMP on pallidal cells were effectively blocked and reversed by
haloperidol. Increasing intravenous doses of l- amphetamine (l-AMP),
totaling 12.8 mg/kg, caused a slight excitation of pallidal neurons. The
average maximum increase was 18.3%. Minor rate- elevating effects were also
observed after systemic administration of desmethylimipramine and
clonidine. The serotonin uptake inhibitor, fluoxetine, produced varied
changes in firing frequencies. Pretreatment with reserpine and
alpha-methyl-p-tyrosine significantly attenuated the d-AMP-induced increase
in pallidal activity. These results suggest that dopamine plays a prominent
role in mediating the stimulatory effects of d-AMP on the firing rates of a
population of globus pallidus cells in gallamine-paralyzed rats.