Editorial: Trends in Neuroendocrinology

Neuroendocrinology is the field of research that explores the interplay between the central nervous system and the endocrine glands. The neuroendocrine system controls a number of essential physiological processes, including biological rhythms, stress, social behaviors, appetite, growth, and reproduction. The present Research Topic is a compilation of contributions stemming from the 8th International Congress of Neuroendocrinology (ICN2014) held in Sydney, NSW, Australia, that illustrates various facets of current neuroendocrinological investigations. Most studies on circadian rhythms have been conducted on male animals only, based on the assumption that females display higher variability caused by the interaction of sex hormones with biological rhythms. The review on sex differences in circadian behavioral rhythms by Krizo and Mintz points out the need to include both female and male animals in such studies to elucidate the influence and mechanism of action of gonadal steroids on behavioral rhythmicity. This review also raises the question of the impact of sex hormone changes across the lifespan, notably during the pubertal period, on the circadian system. The hypothalamo–pituitary–adrenal axis (also called the stress axis) is another fruitful " playground " for neuroendocrinologists. Chen et al. summarize the literature pertaining to the effects of glucocorticoid stress hormones on the nitrergic system notably in the brain. This review clarifies the complex cross-talk between the neuroendocrine stress axis and the nitrergic system that are both implicated in various pathological conditions, including anxiety and depressive disorders. In a sister review, Spiers et al. raise the important question of the effect of glucocorticoids and neuronal oxidative stress. They present the different mechanisms through which cortisol or corticosterone induces oxidative stress, particularly in the hippocampus. There is now strong evidence that oxytocin influences social behavior in various animal models and even in human. Miller and Caldwell examine the organizational role of oxytocin in the postnatal and peripubertal periods on the brain and behaviors. This review highlights the developmental effects of oxytocin on sexual, affiliative, parental, and aggressive behaviors, as well as on non-social behaviors, such as nociception and addiction. It also investigates the neurochemical systems that mediate the effects of oxytocin on these behaviors. Given the effects of oxytocin on prosocial behaviors, a role of oxytocin in the etiology and symptom severity of schizophrenia has been hypothesized. In this context, Rich and Caldwell analyze the possible implication of the oxytocin system in the negative symptoms and deficit in social cognition associated with schizophrenia, and discuss …