Pharmacokinetics and pharmacodynamics of psychotropic drugs: effect of sex.

Data on the specific effects of sex on pharmacokinetics, as well as tolerability, safety, and efficacy of psychotropic medications are still meager, mainly because only recently sex-related issues have attracted a certain degree of interest within the pharmacological domain. Therefore, with the present study, we aimed to provide a comprehensive review of the literature on this topic, through careful MEDLINE and PubMed searches of the years 1990-2012. Generally, data on pharmacokinetics are more consistent and numerous than those on pharmacodynamics. Sex-related differences have been reported for several parameters that influence pharmacokinetics, such as gastric acidity, intestinal motility, body weight and composition, blood volume, liver enzymes (mainly the cytochrome P450), or renal excretion, which may alter plasma drug levels. Sex-related peculiarities may also account for a different sensitivity of men and women to side effects and toxicity of psychotropic drugs. Further, some differences in drug response, mainly to antipsychotics and antidepressants, have been described. Further studies are, however, necessary to explore more thoroughly the impact of sex on the pharmacokinetics and pharmacodynamics of psychotropic drugs, in order to reach the most appropriate and tailored prescription for each patient.

Distribution of serotonin receptor of type 6 (5-HT6) in human brain post-mortem. A pharmacology, autoradiography and immunohistochemistry study.

The aim of this study was to investigate the distribution of serotonin (5-HT) receptors of type 6 (5-HT(6)) in postmortem human prefrontal cortex, striatum and hippocampus. The brain samples were obtained from 6 subjects who had died for causes not involving primarily or secondarily the CNS. The 5-HT(6) receptor distribution was explored by the [(125)I]SB-258585 binding to brain membranes followed by the pharmacological characterization, where possible, and by autoradiographic, immunohistochemical and immunofluorescence evaluations. A specific and saturable [(125)I]SB-258585 binding was detected in striatum only, with a pharmacological characterization consistent with that of a 5-HT(6) receptor. The autoradiography showed the presence of a specific [(125)I]SB-258585 binding distributed homogeneously in caudate, putamen and accumbens. The immunohistochemistry, carried out in the striatum only, coupled with the immunofluorescence with glial fibrillary acidic protein (GFAP) and parvalbumin (PV) showed the co-localization of 5-HT(6) receptor with PV, while indicating that this receptor subtype was expressed in neurons and not in astrocytes. Taken together, the present findings showed the presence of a higher density of 5-HT(6) receptors, as labeled by [(125)I]SB-258585, in striatum than in hippocampus and prefrontal cortex, and specifically within the neuronal body. In addition, they would suggest that striatum is one of the major potential CNS targets linked to 5-HT(6) receptor modulation.

Axonal polineuropathy associated with Sars-CoV 2 infection: a case report.

World healthcare systems are dealing with the pandemic of the severe Coronavirus disease 19 (Covid-19). Covid-19 neurological manifestations affecting both central and peripheral nervous systems have been reported. We describe the case of 44-year-old patient, who was admitted to our Rehabilitation Unit after discharge from intensive care unit for severe Covid-19 related respiratory failure. Neurophysiological investigation revealed an axonal polineuropathy with impairment both of sensory and motor component. He underwent a comprehensive rehabilitation treatment, including breathing exercises and motor rehabilitation. Despite rapid and effective diagnosis and customized progressive rehabilitation treatment, significant improvement in sensory-motor abnormalities has begun but distal complete recovery was not achieved. Indeed, complete indipendence during walking has been partially reached: patient constantly needs two sticks and wears two ankle-foot orthosis during ambulatory function. Nowadays, exploring the neurologic manifestations of Covid-19 may represent a step towards better understanding the virus, preventing longterm sequela and rehabilitation concerns.

Serotonin receptors of type 6 (5-HT6): from neuroscience to clinical pharmacology.

The serotonin (5-HT) receptors of type 6 (5-HT6) are quite different from all other 5-HT receptors, as they include a short third cytoplasmatic loop and a long C-terminal tail, and one intron located in the middle of the third cytoplasmatic loop. A lot of controversies still exist regarding their binding affinity, effects of 5-HT6 ligands on brain catecholamines, behavioral syndromes regulated by them, and brain distribution. In spite of the lack of information on metabolic pattern of the various compounds, some of 5-HT6 receptor ligands entered the clinical development as potential anti-dementia, antipsychotic, antidepressant and anti-obese drugs. The present paper is a comprehensive review on the state of art of the 5-HT6 receptors, while highlighting the potential clinical applications of 5-HT6 receptor agonists/antagonists.