Psychological stress reverses antiaggregatory effects of dietary fish oil

Dietary fish oil does not protect rats exposed to restraint or sleep deprivation stress

It has been suggested that fish oil (FO) prevents weight loss caused by physiological stress such as cancer, injury, or cardiovascular disorders. Previously, we observed that a high-fat diet containing corn and coconut oil exaggerated weight loss caused by the mixed physiological and psychological stress of repeated restraint (RR). This experiment tested the effects of a high-fat diet containing FO as the predominant lipid source in rats exposed to the mixed physiological and psychological stress of either RR or sleep deprivation (SD). FO did not prevent stress-induced hypophagia or weight loss in RR or SD rats but exaggerated the negative effects of stress on body weight in SD rats by promoting loss of lean body mass. RR caused a reduction in body fat content irrespective of dietary treatment. In SD rats, both stress and FO independently reduced body fat mass. FO did not have any effect on adrenal and thymus weights during RR or SD and did not influence corticosterone levels after 1 h of RR or after 48 or 96 h of SD. In conclusion, our results suggest that high levels of dietary FO do not improve the response to stress in rats exposed to mixed stressors.

Platelets and psychiatry: lessons learned from old and new studies

Platelets play an important role not only in hemostasis but also in the pathophysiology of coronary artery disease. The complex interactions among the vascular endothelium, platelets, and blood components are one of the most exciting research areas today. This review addresses some fundamentals of platelet physiology and examines why platelets are interesting probes for neurophysiology. Results of current studies suggest that platelets are affected by diverse stressors, including psychological ones, and that platelets offer an interesting vantage point for understanding the neurophysiology of various psychiatric disorders. We also describe how platelets have been used for various types of research, including studies of stress associated with cardiovascular disease and studies of platelets in psychopharmacological research. Finally, we examine some of the psychiatric literature related to platelets; these studies range from case studies from the 1920s to contemporary experimental studies.