Molecular mechanisms of antipsychotics - their influence on intracellular signaling pathways, and epigenetic and post-transcription processes.

Purpose: The purpose of this paper is to describe some aspects of the intra-cellular mechanism of action of neuroleptics, drugs widely used in psychiatry in treatment of psychotic and affective disorders. The ability of neuroleptics to influence and modify the metabolic, energetic and structural processes of neurons, as well as their apoptosis, probably influence their therapeutic potential. The direct and indirect mechanisms of antipsychotics are discussed on the basis of epigenetic, intra-cellular and post-transcription processes. Views: Antipsychotic drugs facilitate chromatin remodeling, decreasing or increasing histone acetylation, and affect DNA methylation differently. Antipsychotics modulate the intracellular signaling cascades like the cyclic adenosine monophosphate (cAMP), AKT/glycogen synthase kinase-3 (GSK-3) pathway and mitogen-activated protein kinase (MAPK) in a variety of ways that contribute to their different clinical and side-effect profiles. Among the cellular processes involved in the activity of antipsychotics are energy and metabolism, protein synthesis and processing, cytoskeleton functions like microtubule dynamics, dendritic branching, and spine dynamics, as well as cell adhesion and synaptic activity. Finally, antipsychotics have the ability to modulate the expression of a large number of miRNAs, which is related to oxidative stress and metabolism. Conclusions: Despite the efficacy of antipsychotics in treating schizophrenia and bipolar disorders over the last several decades, their molecular mechanisms of action turn out to be very complex and have not yet been fully elucidated. Recent thinking about a more personalized and endophenotype-specific diagnosing and treatment requires a more advanced genomic and proteomic approach and seems to be the next step in the treatment of mental disorders.

Early life trauma - review of clinical and neurobiological studies.

Purpose: Psychological trauma is a significant risk factor for physical and mental health development distortion. This paper presents the results of longitudinal epidemiological surveys and naturalistic observations. It also reviews the results of the most important neurobiological findings in the field of impact of early life trauma on cognitive and emotional development, and the structure and functions of the brain. Views: Trauma is defined as subjective experiences that overwhelm a person's ability to maintain psychophysical integrity. During the stage of neurodevelopment, various life adversities, such as emotional and sensory deprivation, abandonment and neglect by caregivers as well as physical or emotional violence and sexual abuse overwhelm the physiological and mental capacity of a child and impact their cognitive, emotional and social development, adversely influencing adulthood functioning. Symptoms of abused children can evolve and change with time, from moderate signs of distress to more complex symptoms and organized disorders. The most important longitudinal studies, such as the Lives Across Time Study, Minnesota Study, Adverse Childhood Experiences Study, The Great Smoky Mountains Study, and the English and Romanian Adoptee Study are discussed in the paper. The lifelong influences of early adversities on brain structures like the corpus callosum, hippocampus, the amygdaloid nuclei, ventral striatum and cerebral cortex has been described. The variability of the sensitivity of specific brain regions, based on different rates of maturation, has also been discussed. Conclusions: This review integrates and summarizes the basic knowledge about the impact and neurobiological consequences of early traumatic adversities.

Marked elevation of adrenal steroids, especially androgens, in saliva of prepubertal autistic children.

Autism is diagnosed on the basis of behavioral manifestations, but its biomarkers are not well defined. A strong gender bias typifying autism (it is 4-5 times more prevalent in males) suggests involvement of steroid hormones in autism pathobiology. In order to evaluate the potential roles of such hormones in autism, we compared the salivary levels of 22 steroids in prepubertal autistic male and female children from two age groups (3-4 and 7-9 years old) with those in healthy controls. The steroids were analyzed using gas chromatography-mass spectrometry and radioimmunoassay. Statistical analysis (ANOVA) revealed that autistic children had significantly higher salivary concentrations of many steroid hormones (both C21 and C19) than control children. These anomalies were more prominent in older autistic children and in boys. The levels of androgens (androstenediol, dehydroepiandrosterone, androsterone and their polar conjugates) were especially increased, indicative of precocious adrenarche and predictive of early puberty. The concentrations of the steroid precursor, pregnenolone, and of several pregnanolones were also higher in autistic than in healthy children, but cortisol levels were not different. Some steroids, whose levels are raised in autism (allopregnanolone, androsterone, pregnenolone, dehydroepiandrosterone and their sulfate conjugates) are neuroactive and modulate GABA, glutamate, and opioid neurotransmission, affecting brain development and functioning. These steroids may contribute to autism pathobiology and symptoms such as elevated anxiety, sleep disturbances, sensory deficits, and stereotypies among others. We suggest that salivary levels of selected steroids may serve as biomarkers of autism pathology useful for monitoring the progress of therapy.

Neonatal serotonin (5-HT) depletion does not affect spatial learning and memory in rats.

BACKGROUND: Extensive previous research has suggested a role for serotonin (5-HT) in learning and memory processes, both in healthy individuals and pathological disorders including depression, autism and schizophrenia, most of which have a developmental onset. Since 5-HT dysfunction in brain development may be involved in disease etiology, the present investigation assessed the effects of neonatal 5-HT depletion on spatial learning and memory in the Morris water maze (MWM). METHODS: Three days old Sprague-Dawley rats were pretreated with desipramine (20 mg/kg) followed by an intraventricular injection of the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT, 70 µg). Three months later rats were tested in the MWM. RESULTS: Despite a severe and permanent decrease (80-98%) in hippocampal, prefrontal and striatal 5-HT levels, treatment with 5,7-DHT caused no spatial learning and memory impairment. CONCLUSIONS: Limited involvement of chronic 5-HT depletion on learning and memory does not exclude the possibility that this neurotransmitter has an important neuromodulatory role in these functions. Future studies will be needed to identify the nature of the compensatory processes that are able to allow normal proficiency of spatial learning and memory in 5-HT-depleted rats.

The influence of neonatal serotonin depletion on emotional and exploratory behaviours in rats.

Recent studies have shown that neurodevelopmental disturbances in the structure and function of the brain are significant factors in the onset of psychiatric disorders. Such deficits may also affect neurotransmission. Among the different neurotransmitter systems, serotonin (5-HT) plays an important role in the organisation and maturation of brain structures during development. The aim of the present study was to examine the influence of neonatal 5-HT depletion on emotional and exploratory behaviours in adult rats. Three-day-old Wistar male rats received intraventricular injections of the selective serotonin neurotoxin 5,7-dihydroxytryptamine (5,7-DHT). Littermates given saline injections acted as controls. After three months, rat behaviour was analysed in an open field test, a social interaction test and a novel object test. Moreover, contextual-conditioned freezing and ultravocalisation fear responses were studied. The pain reactivity was measured in a flinch-jump test. Biochemical analysis of 5,7-DHT-treated rats revealed a significant decrease in the concentration of 5-HT and its metabolite in the frontal cortex, hippocampus and striatum, with a decreased dopamine level in striatum. Early serotonin depletion reduced locomotor activity in the open field test and attenuated social interaction in non-aversive conditions and exploration of a novel object in adult rats. Ultravocalisation, but not freezing, was increased in the contextual fear-conditioning paradigm in 5-HT-depleted rats. There was no difference in the pain threshold between groups. These data demonstrate that neonatal 5-HT depletion resulted in subtle alterations in the locomotor, exploratory and conditioned fear response of adult animals.

Neonatal serotonin (5-HT) depletion does not disrupt prepulse inhibition of the startle response in rats.

The neurodevelopmental hypothesis of many brain disorders is based on the notion that environmental factors have significant effects on brain maturation. Because serotonin (5-HT) dysfunction in development may be involved in disease etiology, the present investigation assessed the effects of neonatal 5-HT depletion on prepulse inhibition of the startle response (PPI) in rats. Three-day-old Sprague-Dawley rats were pretreated with desipramine (20 mg/kg), followed by an intraventricular injection of the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT, 70 µg dissolved in 2 µl of 0.1% saline solution in ascorbic acid) on each side. Three months later, the rats' PPI was tested. Despite a severe and permanent decrease (80-100%) in hippocampal, prefrontal and striatal 5-HT levels, treatment with 5,7-DHT caused no disruption of PPI. In contrast to this lack of effect, the 5,7-DHT treatment increased basal startle activity, as measured in response to a 120 dB stimulus. Thus, our results clearly indicate that neonatal 5-HT depletion does not interrupt prepulse inhibition in rats. Studies involving lesions of brain structures or chemical systems run the risk of inducing compensatory changes in brain function, resulting in an amelioration of any deficit. The development of such compensatory mechanisms seems likely in the current study, due to the severe and long-lasting effect of neonatal 5,7-DHT-induced reduction on 5-HT levels.

Age-dependent lower or higher levels of hair mercury in autistic children than in healthy controls.

An association between autism and early life exposure to mercury is a hotly debated issue. In this study, 91 autistic Polish children, male and female, 3-4 and 7-9 years old, were compared to 75 age- and sex-matched healthy children with respect to: demographic, perinatal, clinical and developmental measures, parental age, birth order, morphometric measures, vaccination history, and hair mercury content. In demographic and perinatal measures there were no consistent differences between the autistic and control groups. Autistic children had a significantly greater prevalence of adverse reactions after vaccinations and abnormal development than controls. Between 45 and 80% of autistic children experienced developmental regress. Autistic children significantly differed from healthy peers in the concentrations of mercury in hair: younger autistics had lower levels, while older - higher levels than their respective controls. The results suggest that autistic children differ from healthy children in metabolism of mercury, which seems to change with age.

Operant self-administration of ethanol in Warsaw high-preferring (WHP) and Warsaw low-preferring (WLP) lines of rats.

The results of the present experiment demonstrate that ethanol-preferring line of rats (WHP), and ethanol-nonpreferring line of rats (WLP) are able to acquire and maintain lever pressing reinforced by EtOH (oral operant EtOH self-administration) under FR-1 and FR-2 schedule of reinforcement. On the other hand, WHP rats but not WLP rats, displayed the high ability to acquire and maintain robust lever pressing for EtOH under FR-3 procedure. These data suggest that EtOH possesses stronger reinforcing properties in WHP rats. Nevertheless, WLP rats are able to acquire operant self-administration of EtOH when response demand of the reinforcement schedule is lower. Thus, both lines of rats can differ substantially in the amount of EtOH intake when its access is continuous and freely available, but less fundamentally when they respond for EtOH reward under low-demand schedules of partial reinforcement.