Mechanisms of insulin action on sympathetic nerve activity

Insulin resistance and hyperinsulinemia may contribute to the development of arterial hypertension. Although insulin may elevate arterial pressure, in part, through activation of the sympathetic nervous system, the sites and mechanisms of insulin-induced sympathetic excitation remain uncertain. While sympathoexcitation during insulin may be mediated by the baroreflex, or by modulation of norepinephrine release from sympathetic nerve endings, it has been shown repeatedly that insulin increases sympathetic outflow by actions on the central nervous system. Previous studies employing norepinephrine turnover have suggested that insulin causes sympathoexcitation by acting in the hypothalamus. Recent experiments from our laboratory involving direct measurements of regional sympathetic nerve activity have provided further evidence that insulin acts in the central nervous system. For example, administration of insulin into the third cerebralventricle increased lumbar but not renal or adrenal sympathetic nerve activity in normotensive rats. Interestingly, this pattern of regional sympathetic nerve responses to central neural administration of insulin is similar to that seen with systemic administration of insulin. Further, lesions of the anteroventral third ventricle hypothalamic (AV3V) region abolished increases in sympathetic activity to systemic administration of insulin with euglycemic clamp, suggesting that AV3V-related structures are critical for insulin-induced elevations in sympathetic outflow

Editorial Board

Source at http://dx.doi.org/10.1186/s12888-017-1345-8 Background: The duration of untreated psychosis is determined by both patient and service related factors. Few studies have considered the geographical accessibility of services in relation to treatment delay in early psychosis. To address this, we investigated whether treatment delay is co-determined by straight-line distance to hospital based specialist services in a mainly rural mental health context. Methods: A naturalistic cross-sectional study was conducted among a sample of recent onset psychosis patients in northern Norway (n = 62). Data on patient and service related determinants were analysed. Results: Half of the cohort had a treatment delay longer than 4.5 months. In a binary logistic regression model, straight-line distance was found to make an independent contribution to delay in which we controlled for other known risk factors. Conclusions: The determinants of treatment delay are complex. This study adds to previous studies on treatment delay by showing that the spatial location of services also makes an independent contribution. In addition, it may be that insidious onset is a more important factor in treatment delay in remote areas, as the logistical implications of specialist referral are much greater than for urban dwellers. The threshold for making a diagnosis in a remote location may therefore be higher. Strategies to reduce the duration of untreated psychosis in rural areas would benefit from improving appropriate referral by crisis services, and the detection of insidious onset of psychosis in community based specialist services

Evaluative judgments of aspects of life as a function of vicarious exposure to hedonic extremes.

In two experiments, the hypothesis was corroborated that vicarious exposure to hedonic extremes—especially the hedonically negative—results in contrast re-garding evaluative judgments of aspects of life that have evolved or been ac-quired in the course of life beyond the laboratory. In Experiment 1, participants who wrote about hedonically. negative events occurring at the turn of the cen-tury expressed greater satisfaction on a composite index of present life quality than participants who wrote about hedonically positive events. In Experiment 2, participants who wrote about hedonically negative events, personal tragedies, scored higher on a composite index of satisfaction with life, health, and physical appearance than participants who wrote about hedonically positive events. The findings for the composites corroborate a comparison level model of evaluative judgment. The findings for individual items, however, suggest that aspects of life are not evaluated in terms of a single utility scale and standard—the com-parison level. Other findings are discussed that appear to contradict a simple affective model of evaluation in which the positivity of evaluations is postu-lated to increase with the positivity of affective states. A number of psychologists have generalized perceptual (Helson, 1964) and judgmental (Volkmann, 1951) principles, corroborated in the traditional experimental psychology laboratory, to social judgment. The most well-known generalization is that of Thibaut and Kelley (1959) who proposed a theory of the evaluation of outcomes resulting from social interaction. Although outcomes might differ in their specifics, it was assumed that all outcomes could be characterized in terms of their utility or hedonic value. The com-This research was supported by grants from th