Thermo- and photoreceptors of eyes as regulators of circadian rhythm and glymphatic system

Abstract

AbstractThe dynamics of hydrogen bonds in bulk and hydrated water affected the activation energies of temperature dependence of ion currents of voltage-dependent channels that regulate communication and trophic bonds in the neuropil of the cortical parenchyma. The physics of minimizing of isobaric heat capacity of water made it possible to explain stabilization and functional optimization of thermodynamics of eyeball fluids at 34.5 °C and human brain during sleep at 36.5 °C. At these temperatures, thermoreceptors of cornea and cells of ganglionic layer of the retina, through connections with suprachiasmatic nucleus and pineal gland, switch brain metabolism from daytime to nighttime modes. The phylogenesis of circadian rhythm was reflected in dependence of duration of nighttime sleep of mammals on diameter of eyeball, mass of pineal gland, and density of neurons in parenchyma of cortex. The activity of all nerves of eyeball led to division of nocturnal sleep into slow and fast phases. These phases correspond to two modes of glymphatic system - electrochemical and dynamic. The first is responsible for relaxation processes of synaptic plasticity and chemical neutralization of toxins with participation of water and melatonin. Rapid eye movement and an increase in cerebral blood flow in second mode increase water exchange in parenchyma and flush out toxins into venous system.