The involvement of melatonin in mammalian brain pathophysiology has received growing interest, but information about the anatomical distribution of its two G-protein-coupled receptors, MT1 and MT2 , remains elusive. In this study, using specific antibodies, we examined the precise distribution of both melatonin receptors immunoreactivity across the adult rat brain using light, confocal, and electron microscopy. Our results demonstrate a selective MT1 and MT2 localization on neuronal cell bodies and dendrites in numerous regions of the rat telencephalon, diencephalon, and mesencephalon. Confocal and ultrastructural examination confirmed the somatodendritic nature of MT1 and MT2 receptors, both being localized on neuronal membranes. Overall, striking differences were observed in the anatomical distribution pattern of MT1 and MT2 proteins, and the labeling often appeared complementary in regions displaying both receptors. Somadendrites labeled for MT1 were observed for instance in the retrosplenial cortex, the dentate gyrus of the hippocampus, the islands of Calleja, the medial habenula, the suprachiasmatic nucleus, the superior colliculus, the substantia nigra pars compacta, the dorsal raphe nucleus, and the pars tuberalis of the pituitary gland. Somadendrites endowed with MT2 receptors were mostly observed in the CA3 field of the hippocampus, the reticular thalamic nucleus, the supraoptic nucleus, the inferior colliculus, the substantia nigra pars reticulata, and the ventrolateral periaqueductal gray. Together, these data provide the first detailed neurocytological mapping of melatonin receptors in the adult rat brain, an essential prerequisite for a better understanding of melatonin distinct receptor function and neurophysiology.

Non-motor symptoms are gaining relevance in Parkinson's disease (PD) management but little is known about their progression and contribution to deterioration of quality of life. We followed prospectively 707 PD patients (62 % males) for 2 years. We assessed non-motor symptoms referred to 12 different domains, each including 1-10 specific symptoms, as well as motor state (UPDRS), general cognition, and life quality. Hoehn & Yahr (H&Y) stage was used to categorize patient status (I-II mild; III moderate; IV-V severe). We found that individual non-motor symptoms had variable evolution over the 2-year follow-up with sleep, gastrointestinal, attention/memory and skin disturbances (hyperhidrosis and seborrhea) becoming more prevalent and psychiatric, cardiovascular, and respiratory disorders becoming less prevalent. Development of symptoms in the cardiovascular, apathy, urinary, psychiatric, and fatigue domains was associated with significant life-quality worsening (p < 0.0045, alpha with Bonferroni correction). During the observation period, 123 patients (17 %) worsened clinically while 584 were rated as stable. There was a fivefold greater increase in UPDRS motor score in worse compared with stable patients over 24 months (p < 0.0001 vs. baseline both in stable and worse group). The total number of reported non-motor symptoms increased over 24 months in patients with motor worsening compared to stable ones (p < 0.001). Thirty-nine patients died (3.4 % of patients evaluable at baseline) with mean age at death of 74 years. Deceased patients were older, had significantly higher H&Y stage and motor score, and reported a greater number of non-motor symptoms at baseline. In conclusion, overall non-motor symptom progression does not follow motor deterioration, is symptom-specific, and only development of specific domains negatively impacts quality of life. These results have consequences for drug studies targeting non-motor features.

Mutations in the gene leucine-rich repeat kinase 2 (LRRK2) have been recently identified in families with Parkinson's disease (PD). However, the prevalence and nature of LRRK2 mutations, the polymorphism content of the gene, and the associated phenotypes remain poorly understood. We performed a comprehensive study of this gene in a large sample of families with Parkinson's disease compatible with autosomal dominant inheritance (ADPD). The full-length open reading frame and splice sites of the LRRK2 gene (51 exons) were studied by genomic sequencing in 60 probands with ADPD (83% Italian). Pathogenic mutations were identified in six probands (10%): the heterozygous p.G2019S mutation in four (6.6%), and the heterozygous p.R1441C mutation in two (3.4%) probands. A further proband carried the heterozygous p.I1371 V mutation, for which a pathogenic role could not be established with certainty. In total, 13 novel disease-unrelated variants and three intronic changes of uncertain significance were also characterized. The phenotype associated with LRRK2 pathogenic mutations is the one of typical PD, but with a broad range of onset ages (mean 55.2, range 38-68 years) and, in some cases, slow disease progression. On the basis of the comprehensive study in a large sample, we conclude that pathogenic LRRK2 mutations are frequent in ADPD, and they cluster in the C-terminal half of the encoded protein. These data have implications both for understanding the molecular mechanisms of PD, and for directing the genetic screening in clinical practice.

This study investigates motor (MNCS) and sensory (SNCS) nerve conduction in a sample of non-diabetic obese people without symptoms suggestive of neuropathy and looks for a possible metabolic alteration. Twenty-one patients and 20 age-matched controls underwent (a) MNCS (median, ulnar, peroneal, and tibial) and SNCS (median, ulnar, and sural); (b) quantitative sensory testing to measure sensory threshold for vibration, warm and cold sensation (WS-CS), heat and cold-induced pain; and (c) blood sample analysis to evaluate glucose and insulin levels and calculate the quantitative insulin-sensitivity check index (QUICKI). The obese group showed significantly decreased compound muscle action potential amplitude of tibial and peroneal nerves and decreased sensory action potential amplitude of all nerves. Most of the sensory thresholds were altered in obese patients. Insulin serum levels were significantly increased while QUICKI decreased in obese patients. WS and CS from the index and little fingers and WS from the big toe significantly correlated with QUICKI. Thermal and pain thresholds from the index and thermal thresholds from the little finger correlated with QUICKI values. The non-diabetic obese patients showed a subclinical involvement of different diameter sensory fibers. Such impairment was related to hyperinsulinemia and insulin sensitivity. The increase in sensory threshold of obese patients might be due to a metabolic alteration, potentially leading to a future clinical neuropathy.

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Results confirm previous findings showing that in patients with multiple sclerosis quality of life is heavily determined by person's mood, whatever his/her neurological or functional severity. The usefulness and validity of the SF-36 as an index representative of quality of life is debatable, as long as depression explains much of its variance. Further refinement of quality of life definition and measurement is worth further psychometric and statistical research.

The present study addresses the issue of whether a "decision-making disorder" could account for the behavioral problems of severely obese patients (BMI score >34) who are not classified by traditional psychiatric Eating Disorder tests. The neuropsychological test employed, the Gambling Task (GT), is not directly related to the food domain, but it is sensitive to failure in making long-term advantageous choices. A comparison was made of 20 obese subjects (OS) and 20 normal-weight subjects (NWS) matched in age, education and IQ. The subjects' personalities and food behavior were assessed from psychological questionnaires, and then the Gambling Task was administered. The number of "good" choices made by the two groups during GT performance differed significantly, and the OS did not learn to maximize advantageous choices like the NWS did. OS behavior could be consistent with a prefrontal cortex defect that implies difficulties in inhibition of excessive food intake.

SummaryAll three cholesterol oxidation products implicated thus far in the pathogenesis of Alzheimer's disease, 7b-hydroxycholesterol, 24-hydroxycholesterol, and 27-hydroxycholesterol, markedly enhance the binding of amyloidbeta (Ab) to human differentiated neuronal cell lines (SK-N-BE and NT-2) by up-regulating net expression and synthesis of CD36 and b1-integrin receptors. However, only 24-hydroxycholesterol markedly potentiates the proapoptotic and pro-necrogenic effects of Ab 1-42 peptide on these cells: 7b-hydroxycholesterol and 27-hydroxycholesterol, like unoxidized cholesterol, show no potentiating effect. This peculiar behavior of 24-hydroxycholesterol at physiologic concentrations (1 lM) depends on its strong enhancement of the intracellular generation of NADPH oxidase-dependent reactive oxygen species (ROS), mainly H 2 O 2 , and the consequent impairment of neuronal cell redox equilibrium, measured in terms of the GSSG ⁄ GSH ratio. Cell incubation with antioxidants quercetin or genistein prevents 24-hydroxycholesterol's pro-oxidant effect and potentiation of Ab-induced necrosis and apoptosis. Thus, the presence of 24-hydroxycholesterol in the close vicinity of amyloid plaques appears to enhance the adhesion of large amounts of Ab to the plasma membrane of neurons and then to amplify the neurotoxic action of Ab by locally increasing ROS steady-state levels. This report further supports a primary involvement of altered brain cholesterol metabolism in the complex pathogenesis of Alzheimer's disease.