Nicotinic acetylcholine receptors (nAChRs) are present throughout the central nervous system and involved in a variety of physiological and behavioral functions. Nicotinic acetylcholine receptors are receptive to the presence of nicotine and acetylcholine and can be modulated through a variety of agonist and antagonist actions. These receptors are complex in their structure and function, and they are composed of multiple α and β subunits. Many affective disorders have etiological links with developmental exposure to the nAChR agonist nicotine. Given that abnormalities in nAChRs are associated with affective disorders such as depression and anxiety, pharmacological interventions targeting nAChRs may have significant therapeutic benefits.
Kalynn Schulz, Marcia Chavez, and Arthur Castaneda
Michelle T. Foster
In mammals, reproductive function is closely regulated by energy availability. It is influenced by both extremes of nutrition, too few calories (undernutrition) and an excessive amount of calories (obesity). Atypical decreases or increases in weight can have adverse effects on the reproductive axis. This includes suppression of reproductive function, decreases in ovarian cyclicity, reduction in fertility, anovulation, and dysregulation of spermatogenesis. The balance between energy regulation and reproduction is supervised by a complex system comprised of the brain and peripheral tissues. The brain senses and integrates various systemic and central signals that are indicative of changes in body physiology and energy status. This occurs via numerous factors, including metabolic hormones and nutrients. Adipokines, endocrine factors primarily secreted by white adipose tissue, and adipose tissue related cytokines (adipocytokines) contribute to the regulation of maturity, fertility, and reproduction. Indeed, some adipokines play a fundamental role in reproductive disorders. The brain, predominantly the hypothalamus, is responsible for linking adipose-derived signals to pathways controlling reproductive processes. Gonadotropin-releasing hormone (GnRH) cells in the hypothalamus are fundamental in relaying adipose-derived signals to the pituitary–gonadal axis, which consequently controls reproductive processes. Leptin, adiponectin, apelin, chermin, resistin, and visfatin are adipokines that regulate reproductive events via the brain.