Modulation of basal ganglia neurotransmission by the classical antipsychotic fluphenazine is due in part to the blockade of dopamine D1-receptors

The effects of olanzapine and fluphenazine on plasma cortisol, prolactin and muscle rigidity in schizophrenic patients: a double blind study

Pharmacotherapy of schizophrenia is associated with the stressful side effects. Muscle rigidity causes distress, discomfort and poor compliance. The aim of the study was to determine the relationship between plasma hormones (cortisol and prolactin/PRL) and muscle rigidity in female schizophrenic patients treated with olanzapine or fluphenazine. In a randomized, double-blind 22-weeks study, 12 patients were treated with olanzapine (5-20 mg/day) and 10 patients received fluphenazine (6-21 mg/day). Treatment with olanzapine moderately decreased, while treatment with fluphenazine significantly increased plasma cortisol levels and muscle rigidity. The marked and moderate increase in plasma PRL levels were found in patients treated with fluphenazine and olanzapine, respectively. The results suggested that olanzapine induced moderate neuroendocrine effects and a reduction in rigidity as compared to fluphenazine treatment.

Neurochemical changes in the entopeduncular nucleus and increased oral behavior in rats treated subchronically with clozapine or haloperidol

The purpose of the present experiment was to test the possibility that atypical antipsychotics and classical antipsychotics differentially regulate specific neurochemical processes within the entopeduncular nucleus. For these experiments, rats were administered clozapine (25 mg/kg), haloperidol (1 mg/kg), or Tween-80 (control) daily for 21 days. Dopamine D(1)-receptor binding was assessed with in vitro receptor autoradiographic methods and the mRNAs corresponding to the two forms of glutamate decarboxylase (glutamate decarboxylase-65 and glutamate decarboxylase-67) were analyzed using in situ hybridization histochemical methods. In addition, vacuous chewing movements (VCM) were measured throughout the drug administration period as a functional indicator of drug action and changes in striatal dopamine D(2)-receptor binding were measured as a positive control for D(2)-receptor antagonist properties of haloperidol and clozapine. In agreement with previous reports, haloperidol increased D(2)-receptor binding throughout the striatum while clozapine had a more limited impact on D(2)-receptors. Behavioral analysis revealed that both haloperidol and clozapine enhanced the display of vacuous chewing movements to a similar extent but with a different postinjection latency. In the entopeduncular nucleus, clozapine increased D(1)-receptor binding compared to controls while haloperidol was without effect. With respect to the regulation of GAD mRNAs, haloperidol increased glutamate decarboxylase-65 and glutamate decarboxylase-67 mRNA levels throughout the entopeduncular nucleus. The effects of clozapine were restricted to increases in glutamate decarboxylase-65 mRNA. These studies show that clozapine and haloperidol, both of which increase the occurrence of VCM, differentially modulate the neurochemistry of the entopeduncular nucleus.