Anxiety and Depression: What Do We Know of Neuropeptides?

Abstract

In modern society, there has been a rising trend of depression and anxiety. This trend heavily impacts the population’s mental health and thus contributes significantly to morbidity and, in the worst case, to suicides. Modern medicine, with many antidepressants and anxiolytics at hand, is still unable to achieve remission in many patients. The pathophysiology of depression and anxiety is still only marginally understood, which encouraged researchers to focus on neuropeptides, as they are a vast group of signaling molecules in the nervous system. Neuropeptides are involved in the regulation of many physiological functions. Some act as neuromodulators and are often co-released with neurotransmitters that allow for reciprocal communication between the brain and the body. Most studied in the past were the antidepressant and anxiolytic effects of oxytocin, vasopressin or neuropeptide Y and S, or Substance P. However, in recent years, more and more novel neuropeptides have been added to the list, with implications for the research and development of new targets, diagnostic elements, and even therapies to treat anxiety and depressive disorders. In this review, we take a close look at all currently studied neuropeptides, their related pathways, their roles in stress adaptation, and the etiology of anxiety and depression in humans and animal models. We will focus on the latest research and information regarding these associated neuropeptides and thus picture their potential uses in the future.

Blood Levels of Neuropeptide 26RFa in Relation to Anxiety and Aggressive Behavior in Humans—An Exploratory Study

“…The hypothalamicpituitary-adrenal (HPA) axis is another putative target for neuropeptides relevant to the regulation of stress response in the context of altered mood, emotion and aggressive behavior [24,25]. Among the neuropeptides reviewed recently for their implication in anxiety and depression, we do not find 26RFa [26,27]. This lack, however, does not mean that 26RFa has no role in emotional regulation but is explained by the fact that only a few studies with relevant data are available.…”

The Cognitive and Emotional Aspect in Fibromyalgia: The Importance of the Orofacial Sphere

“…This metabolic environment directly stimulates the pain receptors of the thalamus, or indirectly, via the glial cells of the diencephalon, creating a situation of central sensitization with systemic inflammation and pain (neuroinflammation) [ 15 , 21 ]. Substance P is one of the molecules involved in depression and anxiety, and in cognition [ 22 , 23 ].…”

The Mind Body Connection in Dermatologic Conditions: A Literature Review

“…74,75 In animal models, its administration can elicit depressive and anxious behaviors. 74,75 Elevated levels of SP have also been observed in individuals with MDD compared to healthy controls, and levels subsequently drop after they receive treatment for depression. 74 Finally, high BDNF levels in AD patients have been correlated with disease activity, potentially due to its immunomodulatory effects including chemotaxis, inhibition of eosinophil apoptosis, and localization of eosinophils to sensory nerve fibers.…”

“…74,75 Elevated levels of SP have also been observed in individuals with MDD compared to healthy controls, and levels subsequently drop after they receive treatment for depression. 74 Finally, high BDNF levels in AD patients have been correlated with disease activity, potentially due to its immunomodulatory effects including chemotaxis, inhibition of eosinophil apoptosis, and localization of eosinophils to sensory nerve fibers. 76,77 Yeom et al reported that anxious and depressive-like behavior in AD mice was associated with increased BDNF striatal levels and activation in the reward circuitry.…”