The negative syndrome as a dimension: factor analyses of PANSS in major depressive disorder and organic brain disease compared with negative syndrome structures found in the schizophrenia literature.

Objective: To explore the concept of the negative syndrome as a dimensional entity that exists in multiple primary diagnoses, and to compare the negative syndrome in nonschizophrenic disorders and schizophrenia.

Background: Although initially considered specific to schizophrenia, the negative syndrome has subsequently been described in major depression, stroke, and dementia.

Method: We performed an exploratory factor analysis on Positive and Negative Symptom Scale scores of 82 subjects with major depressive disorder and 76 subjects with organic brain disease (dementia or stroke).

Intrastriatal iron perfusion releases dopamine: an in-vivo microdialysis study.

We perfused iron as FeCl(3) directly into the striatum of normal rats and used the in vivo microdialysis technique to monitor striatal levels of dopamine (DA). KCl was perfused to assess the functional integrity of the DA receptors at the end of each dialysis experiment. Cu(+2) (as CuSO(4)) and Cl(-) (as NaCl) were perfused to compare the effects of Fe(+3) to that of other heavy metal and donors of Cl(-) anion.

COMT-dependent protection of dopaminergic neurons by methionine, dimethionine and S-adenosylmethionine (SAM) against L-dopa toxicity in vitro.

L-dopa may be toxic to dopamine neurons, possibly due to catechol-autoxidation. Catechols are O-methylated by catechol-O-methyltransferase (COMT) in a SAM consuming reaction, preventing the initiation of catechol autoxidation. We hypothesized that SAM or SAM-precursors ameliorate L-dopa neurotoxicity, in a COMT-dependent fashion.

Comparative effects of repeated administration of dopamine agonists on circling behavior in rats.

A paucity of studies are available concerning the comparative therapeutic effectiveness of presently available dopamine agonist agents in the control of Parkinson symptoms. To provide a basis for resolving this issue, we measured the circling response in unilaterally nigrotomized (6-OHDA) rats following the administration of ropinirole, pramipexole, pergolide, bromocriptine, and cabergoline. Cabergoline, and to a lesser extent pergolide, produced the most vigorous and longest lasting circling response.

Sertraline induced parkinsonism. A case report and an in-vivo study of the effect of sertraline on dopamine metabolism.

We report a patient with a parkinsonian syndrome induced by sertraline (Zoloft), an SSRI antidepressant, whose symptoms resolved after the drug was discontinued. This case prompted us to investigate the effect of sertraline on dopamine metabolism in animals. Sertraline (30 mg/kg, i.