Abstract
The biological origin of circumventricular organs (CVOs) and the hypothalamus evolutionally goes back to invertebrates and even to plants. There are resting and action types of behavior of the hypothalamus. The resting hypothalamus (ventromedial hypothalamus and arcuate nucleus inhibiting eating behavior) facilitates vagal, pelvic and oculomotor parasympathetic nerves, and sympathetic nerves innervating the liver and spleen. The action hypothalamus (lateral hypothalamus and arcuate nucleus facilitating eating behavior) facilitates the cardiac sympathetic nerves and the hypothalamic-pituitary-adrenal axis. There are sensory CVOs (subfornical organ, organum vasculosum of lamina terminalis, and area postrema) and secretory CVOs (neurohypophysis, pineal gland, subcommissural organ, and median eminence). Physiological mechanisms of life-saving homeostasis arising from the hypothalamus and CVOs consist of seven axes: the autonomic nervous system axis, the circadian rhythm axis, the neuroendocrine axis, the emotion and memory axis, the pain and sensation axis, the gait and motion axis, and the neurometabolism and neuroimmunity axis (eating and drinking behavior, heat energy metabolism, waste clearance, innate immunity). Thus, CVOs and the hypothalamus contribute to a wide spectrum of regulation axes, whose impairments result in complex symptoms composed of sleep-related, cardiovascular, gastrointestinal, menstrual, emotional, cognitive, sensory, and motor symptoms. We propose a new clinical concept “hypothalamic syndrome,” or “circumventricular organ dysregulation syndrome,” to describe a range of known disorders including human papilloma virus vaccination-associated neuro-immunopathic syndrome (HANS), von Economo’s encephalitis lethargica, craniopharyngioma, interferon encephalopathy, metronidazole-induced encephalopathy, Wernicke’s encephalopathy, schizophrenia with water intoxication, Alzheimer’s disease with overeating, neuromyelitis optica, stiff-person syndrome, cerebrospinal fluid hypovolemia, heat stroke, fibromyalgia, chronic fatigue syndrome / myalgic encephalomyelitis, menopausal syndrome, frailty syndrome (sarcopenia syndrome), and environmental hypersensitivity.
