Peculiar modulation of taste aversion learning by the time of day in developing rats.

The ontogeny of the temporal context modulation of conditioned taste aversion was studied in male Wistar rats using a palatable 1% NaCl solution. A procedure that included two saline preexposures, a single pairing saline-lithium chloride (0.15 M; 1% b.w.) either at the same or a different time of day of preexposures and a one-bottle test at the same time than preexposure was applied. Four age groups (PN32, PN48, PN64, and PN100) covering the complete range from adolescence to the adult period were tested. The results showed no effect of a temporal context shift in PN32. A peculiar enhancement of temporal context-specific saline aversions was exhibited by PN48 and PN64 rats, while the adult typical temporal context specificity of latent inhibition was only evident in PN100 rats. The results are discussed in terms of the peculiar brain functional organization during a protracted adolescence period.

A severe case of olanzapine overdose with analytical data.

INTRODUCTION: Olanzapine is a second-generation atypical antipsychotic agent approved for the treatment of psychotic disorders and mania. While olanzapine overdoses are common, cases with whole blood concentrations are less so. We describe here a well-documented case of a pure olanzapine overdose in which whole blood concentrations were determined, and compared with other concentrations in the literature. CASE REPORT: A 58-year-old woman with a 10-year history of paranoid schizophrenia and poor therapeutic compliance was found unconscious with two empty 28-tablet vials of Zyprexa (olanzapine) 10 mg tablets. Her initial vital signs were blood pressure 110/70 mmHg, pulse rate 82 beats/minute (sinus rhythm), respirations 20 breaths/minute, and the Glasgow Coma Scale score was 7. In the Intensive Care Unit, her pulse rate was 160 beats/minute, in sinus rhythm, and QTc 0.423 seconds (normal <0.4 seconds). Relevant analytical findings were metabolic acidosis, leukocytosis, creatine phosphokinase 1992 mg/dL, and glucose 207 mg/dL. Ten hours after being found, her blood sugar was 350 mg/dL and became normal at 25 hours. The patient needed intubation and insulin. RESULTS: Olanzapine was detected and quantitated by gas chromatography with nitrogen-phosphorus detector and confirmed by gas chromatography-mass spectrometry using a validated analytical method. At approximately 4, 8, and 12 hours post-ingestion, whole blood concentrations of olanzapine were 0.41, 0.34, and 0.38 mg/L, respectively. CONCLUSIONS: This study reports an acute olanzapine monointoxication with severe toxicity and high whole blood olanzapine concentrations. Clinical and analytical data of similar samples obtained in non-fatal life-threatening cases can be very useful when interpreting postmortem cases.

Time of day-dependent latent inhibition of conditioned taste aversions in rats.

We have determined that the temporal context of drinking can modulate latent inhibition of learned saline aversions in Wistar rats by changing the time of day of drinking of the preexposure and conditioning phases. Latent inhibition was absent in the group preexposed and conditioned to saline at different times of the day, but not in the group that was preexposed and conditioned at the same time of day. The results confirm a previous report that the time of day can modulate taste aversion learning independently of other environmental cues. It is proposed that the features and duration of the habituation training to the temporal contexts used may be critical for time-dependent latent inhibition to appear.