Carlos Torner

Ultrastructural changes and immunolocalization of P-selectin in platelets from patients with major depression

Depression is considered an important risk factor in patients with cardiovascular disease (CVD). Although the biological mechanism is unknown, it has been suggested that hyperactivity of platelets may have an important role in the onset and evolution of cardiovascular damage. The goals of this study were to evaluate by transmission electron microscopy and immunohistochemistry the presence of ultra-structural variations in platelets from individuals with recent diagnosis of major depression disease (MDD, patients without previous anti-depressant treatment and from healthy control subjects.). Platelets from depressed patients had a greater proportion of dendritic forms compared with those obtained from control subjects. Morphological changes, such as dilation of open canalicular and dense tubular systems, platelet vacuolization, electrodense pattern of membranes, and a different immunolocalization of P-selectin were observed in the platelets from depressed patients compared with those isolated from healthy subjects. Our results revealed ultra-structural changes in platelets isolated from patients with MDD suggestive of enhanced platelet activation.

Diurnal variations of extrapyramidal symptoms induced by haloperidol in schizophrenic subjects

Despite the fact that the circadian variations in the density of striatal dopaminergic D2 receptors are well documented, there are few reports concerning whether these variations may regulate the extrapyramidal symptoms produced by antipsychotic drugs. To test this hypothesis, we selected 18 male hospitalized schizophrenic subjects, who had been treated for 2 wk with 10 mg haloperidol three times a day. The extrapyramidal symptoms were evaluated 1 h after each haloperidol administration (e.g. 09:00, 14:00 and 19:00 hours). The diurnal profiles of haloperidol-induced extrapyramidal symptoms showed that akathisia and dystonia were milder in the morning and increased in severity during the night. However, Parkinsonian symptoms were more severe during the morning evaluations than during the evening tests. The difference in the diurnal pattern of the haloperidol-induced side-effects, suggests that receptor-related mechanisms with a different circadian profile contribute to the induction of the extrapyramidal symptoms.

Asynchrony in the Diurnal Rhythms of Dopaminergic D2 Receptors in Different Brain Regions of the Rat

Diurnal variations of dopaminergic D2 receptors have been described in the striatum of rats, while other dopaminergic regions remain unstudied. Diurnal variations of dopamine D2 receptors in the striatum, frontal cortex, and amygdala of the rat, were characterized by the stereospecific binding of [3H]-spiperone. Clear rhythms were found in all these areas, but asynchronous to each other. Striatal receptors had diurnal variations with a single peak at 00:00 hours. Frontal cortex receptors showed two peaks at 00:00 and 12:00 hours. Amygdaline complex receptors had two peaks at 18:00 and 06:00 hours. Saturation binding curves and their Scatchard analysis indicated that the diurnal variations in [3H]-spiperone binding are related to changes in receptor density rather than its affinity. The diurnal variations asynchrony in [3H]-spiperone binding to dopaminergic D2 receptors from different neural regions, suggest different regulation in each area. Other functional implications of these rhythms remains to be established.