title: Biphasic locomotor response to intra-accumbens dopamine in a nonhuman primate.
abstract: Locomotor activity of ten squirrel monkeys, Saimiri sciureus, was evaluated by means of a photocell activity cage following intracranial application of dopamine (DA). A biphasic response consisting of an initial quiet period followed by increased locomotor activity was seen following intra-accumbens DA, 12.5--100 micrograms bilaterally. Both the length of the quiet phase and intensity of locomotor activity were positively related to DA dose. Intra-caudate DA (50 micrograms) was significantly less effective in producing locomotor effects. The specificity of the DA response was substantiated by dose-related inhibition with both systemic (0.1 or 0.05 mg/kg) and intra-accumbens (2--10 micrograms) administration of the DA antagonist haloperidol. Additionally, the intra-accumbens application of haloperidol was found to be ineffective in inducing catalepsy, a state readily produced by systemically administered haloperidol.
mesh_terms: D000818:Animals; D002375:Catalepsy / Q000139:chemically induced; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007267:Injections; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects*; D012453:Saimiri; D012686:Septal Nuclei / Q000187:drug effects*
chemical_list: D006220:Haloperidol; D004298:Dopamine