Roles of fibroblast growth factor 21 in the control of depression-like behaviours after social defeat stress in male rodents.

Fibroblast growth factor 21 (FGF21) modulates energy metabolism and neuroendocrine stress responses. FGF21 synthesis is increased after environmental or metabolic challenges. Detailed roles of FGF21 in the control of behavioural disturbances under stressful conditions remain to be clarified. Here, we examined the roles of FGF21 in the control of behavioural changes after social defeat stress in male rodents. Central administration of FGF21 increased the number of tyrosine hydroxylase-positive catecholaminergic cells expressing c-Fos protein, an activity marker of neurones, in the nucleus tractus solitarius and area postrema. Double in situ hybridisation showed that some catecholaminergic neurones in the dorsal medulla oblongata expressed ß-Klotho, an essential co-receptor for FGF21, in male mice. Social defeat stress increased FGF21 concentrations in the plasma of male mice. FGF21-deficient male mice showed social avoidance in a social avoidance test with C57BL/6J mice (background strain of FGF21-deficient mice) and augmented immobility behaviour in a forced swimming test after social defeat stress. On the other hand, overexpression of FGF21 by adeno-associated virus vectors did not significantly change behaviours either in wild-type male mice or FGF21-deficient male mice. The present data are consistent with the view that endogenous FGF21, possibly during the developmental period, has an inhibitory action on stress-induced depression-like behaviour in male rodents.

Increased fibroblast growth factor-21 in chronic kidney disease is a trade-off between survival benefit and blood pressure dysregulation.

Circulating levels of fibroblast growth factor-21 (FGF21) start increasing in patients with chronic kidney disease (CKD) since early stages during the cause of disease progression. FGF21 is a liver-derived hormone that induces responses to stress through acting on hypothalamus to activate the sympathetic nervous system and the hypothalamus-pituitary-adrenal endocrine axis. However, roles that FGF21 plays in pathophysiology of CKD remains elusive. Here we show in mice that FGF21 is required to survive CKD but responsible for blood pressure dysregulation. When introduced with CKD, Fgf21-/- mice died earlier than wild-type mice. Paradoxically, these Fgf21-/- CKD mice escaped several complications observed in wild-type mice, including augmentation of blood pressure elevating response and activation of the sympathetic nervous system during physical activity and increase in serum noradrenalin and corticosterone levels. Supplementation of FGF21 by administration of an FGF21-expressing adeno-associated virus vector recapitulated these complications in wild-type mice and restored the survival period in Fgf21-/- CKD mice. In CKD patients, high serum FGF21 levels are independently associated with decreased baroreceptor sensitivity. Thus, increased FGF21 in CKD can be viewed as a survival response at the sacrifice of blood pressure homeostasis.

For Whom Does Determinism Undermine Moral Responsibility? Surveying the Conditions for Free Will Across Cultures.

Philosophers have long debated whether, if determinism is true, we should hold people morally responsible for their actions since in a deterministic universe, people are arguably not the ultimate source of their actions nor could they have done otherwise if initial conditions and the laws of nature are held fixed. To reveal how non-philosophers ordinarily reason about the conditions for free will, we conducted a cross-cultural and cross-linguistic survey (N = 5,268) spanning twenty countries and sixteen languages. Overall, participants tended to ascribe moral responsibility whether the perpetrator lacked sourcehood or alternate possibilities. However, for American, European, and Middle Eastern participants, being the ultimate source of one's actions promoted perceptions of free will and control as well as ascriptions of blame and punishment. By contrast, being the source of one's actions was not particularly salient to Asian participants. Finally, across cultures, participants exhibiting greater cognitive reflection were more likely to view free will as incompatible with causal determinism. We discuss these findings in light of documented cultural differences in the tendency toward dispositional versus situational attributions.