Prosaposin is the precursor of four sphingolipid activator proteins (saposins A, B, C, and D) for lysosomal hydrolases and is abundant in the nervous system and muscle. In addition to its role as a precursor of saposins in lysosomes, intact prosaposin has neurotrophic effects in vivo or in vitro when supplied exogenously. We examined the distribution of prosaposin in the central and peripheral nervous systems and its intracellular distribution. Using a monospecific antisaposin D antibody that crossreacts with prosaposin but not with saposins A, B, or C, immunoblot experiments showed that both the central and peripheral nervous systems express unprocessed prosaposin and little saposin D. Using the antisaposin D antibodies, we demonstrated that prosaposin is abundant in almost all neurons of both the central and peripheral nervous systems, including autonomic nerves, as well as motor and sensory nerves. Immunoelectron microscopy using double staining with antisaposin D and anticathepsin D antibodies showed strong prosaposin immunoreactivity mainly in the lysosomal granules in the neurons in both the central and peripheral nervous systems. The expression of prosaposin mRNA, examined using in situ hybridization, was observed in these same neurons. Our results suggest that prosaposin is synthesized ubiquitously in neurons of both the central and peripheral nervous systems.

Background: Common adverse effects of atypical antipsychotic treatments for schizophrenia are weight gain and lipid metabolism abnormality. We aimed to identify the signs of metabolic problems with continuous atypical antipsychotic treatment for schizophrenia over a 2-year period. Methods: The participants were 68 schizophrenic patients (29 males, 39 females; ages 53.4 ± 13.5 years old). Changes in carbohydrate metabolism and changes in physical characteristics were studied over a 2-year period. In addition, functional single nucleotide polymorphisms in the transcriptional regulatory region of the resistin gene were examined. Results: We found no changes in the mental state of the participants over a 2-year period. Patients did show a significant decrease in total cholesterol and hemoglobin A1c levels, although physical changes such as body mass index and abdominal girth, were not observed. The amount of resistin may not be associated with mental states and physical parameters. Conclusions: We could not find physical factors related to metabolic changes of antipsychotics in this 2-year study. However, several psychological factors, such as health-related thoughts and behaviors, should be studied in the future.

Nocturnal eating/drinking syndrome is characterized by awakening in the middle of the night, getting out of bed, and consuming large quantities of food quickly and uncontrollably. We report a middle-aged male patient with schizophrenia who had nocturnal eating/drinking syndrome with restless legs syndrome whose condition improved with the administration of the herbal medicine Yi-Gan San (Yokukan-San in Japanese).