Pharmacological treatment of patients with schizophrenia. Past and present problems and potential future therapy

Nonpeptide angiotensin II receptor antagonists: synthesis, biological activities, and structure-activity relationships of imidazole-5-carboxylic acids bearing alkyl, alkenyl, and hydroxyalkyl substituents at the 4-position and their related compounds

A series of imidazole-5-carboxylic acids bearing alkyl, alkenyl, and hydroxyalkyl substituents at the 4-position and their related compounds were prepared and evaluated for their antagonistic activities to the angiotensin II (AII) receptor. Among them, the 4-(1-hydroxyalkyl)-imidazole derivatives had strong binding affinity to the AII receptor and potently inhibited the AII-induced pressor response by intravenous administration. Various esters of these acids showed potent and long-lasting antagonistic activity by oral administration. The most promising compounds were (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (CS-866) and (pivaloyloxy)-methyl esters of 4-(1-hydroxy-1-methylethyl)-2-propyl-1-[(2'-1H-tetrazol-5- ylbiphenyl-4-yl)-methyl]imidazole-5-carboxylic acid (26c). A study involving stereochemical comparison of 26c with the acetylated C-terminal pentapeptide of AII was also undertaken.

Single preexposure to fluphenazine produces persisting behavioral sensitization accompanied by tolerance to fluphenazine-induced striatal dopamine overflow in rats

Single, previous exposure to a neuroleptic has been shown to produce long-lasting changes in various measures of behavior and neurochemistry upon subsequent drug exposure. The present study examined the effects of a single preexposure to fluphenazine (0.3 or 1.0 mg/kg) or vehicle on the effects of subsequent fluphenazine administration 15 or 30 days later. Intracranial microdialysis was used to assess changes in striatal extracellular dopamine concentrations. Animals were tested for catalepsy response on a horizontal bar test while concurrently collecting dialysis samples. Previous fluphenazine exposure produced a profound tolerance to the effects of subsequent fluphenazine at day 15 or day 30 on increasing extracellular dopamine levels. In addition, animals that had received fluphenazine on the first trial showed significant sensitization to the cataleptic effects of fluphenazine at both time points. Pretreatment with vehicle did not result in tolerance to dopamine overflow and there was only minimal evidence of cataleptic sensitization to a subsequent fluphenazine challenge. Although the tolerance to dopamine overflow may only indirectly relate to behavioral sensitization, these results support the hypothesis that significant behavioral and neurochemical alterations persist for prolonged time periods following single neuroleptic exposure.

The clinical relevance of an auditory attention task (PAT) in a longitudinal study of chronic schizophrenia, with placebo substitution for chlorpromazine

A new auditory attention task (PAT) is described. The test comprises four different subtest combinations (diotic/dichotic, slow/fast) each of 5 min duration. Omission and commission errors are combined by an index of errors (IE). The PAT was given fortnightly to 20 chronic schizophrenic inpatients for more than one year. Independent psychiatrists rated the patients according to the Brief Psychiatric Rating Scale and a Global Rating Scale. All measures yielded significant test-retest reliabilities. The patients were stabilized on individualized doses of chlorpromazine (CPZ) and randomized to two groups. Placebo was substituted for CPZ during 10 weeks, according to a double-blind cross-over design. Significant deterioration under placebo was detected by all three methods, but the PAT was the most sensitive to change. The PAT mean score (M IE) was correlated with both rating scales. Unlike the rating scales, it also correctly ordered the twenty patients along a dimension which measured the severity of illness and 'predicted' hospital discharge.

Effects of placebo, orphenadrine, and rising doses of chlorpromazine, on PAT performance in chronic schizophrenia. A two year longitudinal study

An earlier study (Study 1: 14 months duration) showed that the PAT (an auditory attention task) is sensitive to changes of clinical state in chronic schizophrenia and is able to predict hospital discharge. The newly presented study (Study 2: 12 months duration) investigated the effects of increasing the dose of chlorpromazine (CPZ) stepwise (double-blind) to between 900 mg and 1800 mg per day, in 10 of the original 20 patients. Measurements were made fortnightly throughout both studies and the data were depicted continuously for each patient. Study 2 showed that a 300% increase of CPZ dose neither improved nor impaired PAT performance. Also, the addition of orphenadrine 300 mg per day had no significant effect on performance. Four types of relapse were detected. The first was induced by placebo substitution for CPZ and recovered when the drug was reinstated. The remaining types of relapse were all resistant to CPZ and comprised: a long-period pattern with a spontaneous reversal; unremitting deterioration; and a short-period pattern of labile relapse and recovery.