主题词：Tryptophan and brain disorders; Stress Responses and Cortisol; Neuroinflammation and Neurodegeneration Mechanisms; Neuroendocrine regulation and behavior; Immune Response and Inflammation; Cancer, Stress, Anesthesia, and Immune Response; Pain Mechanisms and Treatments; Gut microbiota and health; Immune Cell Function and Interaction; Neuropeptides and Animal Physiology; Circadian rhythm and melatonin; Fibromyalgia and Chronic Fatigue Syndrome Research; Neurogenesis and neuroplasticity mechanisms; Neuroscience and Neuropharmacology Research; Exercise and Physiological Responses; Birth, Development, and Health; Alzheimer's disease research and treatments; Immune cells in cancer; Long-Term Effects of COVID-19; Maternal Mental Health During Pregnancy and Postpartum; Adipokines, Inflammation, and Metabolic Diseases; COVID-19 and Mental Health; Reproductive System and Pregnancy; Receptor Mechanisms and Signaling; Sleep and related disorders