[Barbiturates as hypnotics].

Barbiturates had been playing an important role in treating insomnia for more than 100 years. To date, benzodiazepines and related compounds seem to be superseding the role of barbiturates because of their relative safeness. In this article, a brief summary on barbiturates as hypnotics is described including the history of development, mechanism of action, and disadvantageous pharmacological properties that limit application as sleep-inducing medication. Unrecognized problems concerning barbiturate prescription in Japan are also discussed.

High-dose of multiple antipsychotics and cognitive function in schizophrenia: the effect of dose-reduction.

We evaluated the effect of antipsychotic dose-reduction on the neurocognitive function of 17 schizophrenic patients (11 male and 6 female, mean age=42.4+/-11.3) who have been taking high-doses of multiple conventional antipsychotics. The mean (+/-SD) of total daily antipsychotic doses (in mg/day, chlorpromazine-equivalent) was 2,253 (+/-668) at baseline, which was reduced to 1,315 (+/-276). Possible changes in neurocognitive function were assessed using Wisconsin card sorting test (WCST) and continuous performance test (CPT). As controls, we examined WCST and CPT in 6 schizophrenic patients (4 male and 2 female, mean age=47.7+/-14.2) who had been taking high-doses of multiple antipsychotics (mean daily antipsychotic dose=1,753+/-165 mg) and declined to change their antipsychotic regimen. In WCST, the mean number of total correct answers significantly increased (53.2+/-16.3 vs. 63.8+/-19.6, P=0.035, Wilcoxon signed rank test); perseverative errors significantly decreased (54.4+/-27.3 vs. 35.4+/-20.1, P=0.013, Wilcoxon signed rank test) after the antipsychotic dose-reduction. In contrast, the control group showed no significant difference between the two WCST performances conducted with a three-month interval. The improvements in WCST performance significantly correlated with the decreases in PANSS negative syndrome score in the subject patients. No significant change was observed in CPT performances in either group. Our preliminary data shows that, in schizophrenic patients taking high-doses of multiple conventional antipsychotics, dose-reduction might lead to improvements in cognitive functions.

Risperidone failed to improve polydipsia-hyponatremia of the schizophrenic patients.

The effect of risperidone on polydipsia-hyponatremia was evaluated in six hospitalized schizophrenic patients. The normalized diurnal weight gain (NDWG), urine-specific gravity (USG), urine and plasma osmolarity, and serum sodium were monitored during 9 months of risperidone treatment. The dose of risperidone (mean +/- SD=8.0 +/- 1.0, range=6-9 mg/day) was determined as approximately half of the haloperidol-equivalent dose of previous neuroleptics. Before risperidone treatment, the mean (+/- SD) BPRS score was 23.5 +/- 7.1; no significant improvement was observed after risperidone (22.0 +/- 7.5). The subjects showed relatively high serum prolactin before risperidone treatment (mean +/- SD=16.5 +/- 9.7 ng/mL), that was not significantly decreased by risperidone (14.2 +/- 7.9 ng/mL). The monthly means (+/- SD) of NDWG and USG before risperidone were 5.5 +/- 1.5 (%) and 1.002 +/- 0.001, respectively. These and other indices did not significantly improve throughout the study period. Although the sample size is relatively small, our preliminary data showed that risperidone might not be effective on polydipsia-hyponatremia of schizophrenic patients.

Repeated cocaine administration increases GABA(B(1)) subunit mRNA in rat brain.

The effects of a single and repeated administration of cocaine on GABA(B) receptor subunit mRNA was investigated in rat brain by in situ hybridization. Following a single administration of cocaine, no significant change was observed in any brain regions examined, neither 1 h nor 24 h after administration. During repeated administration of cocaine, behavioral sensitization with increased stereotyped behavior was observed. A significant increase in the level of GABA(B(1)) mRNA was observed in the nucleus accumbens (11.4%), CA1 field of the hippocampus (16.8%), and thalamus (16.5%) 1 day after repeated administrations of cocaine for 14 consecutive days. The level of mRNA returned to the basal level 1 week after the final injection of repeated cocaine treatment. The observed changes in the mRNA level after the repeated cocaine may imply changes of GABA(B(1)) subunit in molecular mechanisms which underlie development of behavioral sensitization.