Among the atypical antipsychotics, clozapine appears to have a simultaneous and equivalent occupancy of dopamine D(1) and D(2) receptors. Whether its effect on D(1) receptors represents agonism or antagonism is not yet clear, as this issue is still unresolved in the preclinical arena. This distinctive effect on D(1)/D(2) receptors may be responsible for clozapine's unique effectiveness in patients with schizophrenia refractory to other typical and atypical antipsychotics.

H]arginine binding to BA 9 did not differ between groups, and there was no specific binding of [ 3 H]raclopride or 7-hydroxy-2-(di-n-[ 3 H]propylamino)tetralin to BA 9 from either cohort of subjects. This suggests the density of dopamine D 1 -like and NMDA receptors, the dopamine transporter, and nitric oxide synthase activity are not altered in BA 9 from schizophrenic subjects. The selective nature of the changes in serotonin 2A and GABA A receptors in DLPFC could indicate that these changes are involved in the pathology of schizophrenia.

No abstract

Pergolide, a dopamine receptor agonist, given daily i.p. for three weeks at 0.04 mg/kg and 0.4 mg/kg, significantly induced soluble (Cu-Zn) superoxide dismutase in the rat striatum, while having no effect on the mitochondrial (Mn) form of the enzyme. Such induction, which can also be effected by (-)-deprenyl, may help to protect against nigrostriatal degeneration.