Rhythmic control of endocannabinoids in the rat pineal gland

Melatonin and cannabinoids: mitochondrial-targeted molecules that may reduce inflammaging in neurodegenerative diseases

Generally, the development and progression of neurodegenerative diseases are associated with advancing age, so they are usually diagnosed in late adulthood. A primary mechanism underlying the onset of neurodegenerative diseases is neuroinflammation. Based on this background, the concept of "neuroinflammaging" has emerged. In this deregulated neuroinflammatory process, a variety of immune cells participate, especially glial cells, proinflammatory cytokines, receptors, and subcellular organelles including mitochondria, which are mainly responsible for maintaining redox balance at the cellular level. Senescence and autophagic processes also play a crucial role in the neuroinflammatory disease associated with aging. Of particular interest, melatonin, cannabinoids, and the receptors of both molecules which are closely related, exert beneficial effects on the neuroinflammatory processes that precede the onset of neurodegenerative pathologies such as Parkinson's and Alzheimer's diseases. Some of these neuroprotective effects are fundamentally related to its anti-inflammatory and antioxidative actions at the mitochondrial level due to the strategic functions of this organelle. The aim of this review is to summarize the most recent advances in the study of neuroinflammation and neurodegeneration associated with age and to consider the use of new mitochondrial therapeutic targets related to the endocannabinoid system and the pineal gland.

Cannabinoid Signaling Recruits Astrocytes to Modulate Presynaptic Function in the Suprachiasmatic Nucleus

Circadian rhythms are 24-h cycles in physiology regulated by the suprachiasmatic nucleus (SCN) in the brain, where daily cues act on SCN neurons to alter clock timing. Cannabinoid signaling modulates SCN neuronal activity, although the mechanism remains unclear. We propose that neuronal activity generates endocannabinoid release, activating astrocyte Ca²⁺ signaling, which releases adenosine and activates adenosine-1 receptors (A1Rs) on the presynaptic axon terminals, decreasing GABA release. We demonstrated, in mice, that activation of cannabinoid-1 receptors (CB1R) with the agonist WIN 55,212-2 (WIN) reduced the miniature GABA receptor-mediated postsynaptic current (mGPSC) frequency by a mechanism that requires astrocytes and A1R. WIN activated an intracellular Ca²⁺ signaling pathway in astrocytes. Activating this intracellular Ca²⁺ pathway with designer receptors exclusively activated by designer drugs (DREADDs) also decreased the mGPSC frequency and required A1R activation. The frequency of spontaneous Ca²⁺ events, including those induced by depolarization of a postsynaptic SCN neuron, was reduced by blocking CB1R activation with AM251, demonstrating neuronal endocannabinoid signaling modulates astrocytic Ca²⁺ signaling in the SCN. Finally, daytime application of WIN or adenosine phase advanced the molecular circadian clock, indicating that this cannabinoid signaling pathway is vital for the timing of circadian rhythms.

Saliva cortisol, melatonin levels and circadian rhythm alterations in Chinese primary school children with dyslexia

Cortisol is the main end product of hypothalamic-pituitary-adrenal gland (HPA axis), and melatonin (MT) has a regulating effect on HPA axis, and both are closely related to individual behavior and cognitive function. We aimed to evaluate cortisol and MT roles on children dyslexia in this study.A total of 72 dyslexic children and 72 controls were recruited in this study. Saliva samples were collected in the morning, afternoon, and night, respectively. The levels of saliva cortisol and MT were measured by enzyme-linked immunosorbent assay method. Differences of cortisol and MT levels between dyslexic and normal children were compared, and the variation trend was also analyzed by dynamic monitoring in 3 time points.The levels of salivary cortisol and MT in children with dyslexia were all lower than those in normal children whether in the morning (7:30-8:30 AM ), at afternoon (15:30-16:30 PM ) or at night (21:30-22:30 PM ) (all P < .001). Compared with normal children, the circadian rhythm variations of salivary cortisol and MT in dyslexic children disappeared and became disordered. The salivary cortisol and MT levels in children with dyslexia were declined throughout the day; and the circadian rhythm was disordered or disappeared.The results suggest that cortisol and MT levels and their circadian rhythm may affect children dyslexia, but the mechanisms need further exploration.