Impact of endogenous melatonin on rhythmic behaviors, reproduction, and survival revealed in melatonin-proficient C57BL/6J congenic mice.

The hormone melatonin is synthesized from serotonin by two enzymatic reactions (AANAT and ASMT/HIOMT) in the pineal gland following a circadian rhythm with low levels during the day and high levels at night. The robust nightly peak of melatonin secretion is an output signal of the circadian clock to the whole organism. However, so far the regulatory roles of endogenous melatonin in mammalian biological rhythms and physiology processes are poorly understood.

MT1 and MT2 Melatonin Receptors: A Therapeutic Perspective.

Melatonin, or 5-methoxy-N-acetyltryptamine, is synthesized and released by the pineal gland and locally in the retina following a circadian rhythm, with low levels during the day and elevated levels at night. Melatonin activates two high-affinity G protein-coupled receptors, termed MT1 and MT2, to exert beneficial actions in sleep and circadian abnormality, mood disorders, learning and memory, neuroprotection, drug abuse, and cancer. Progress in understanding the role of melatonin receptors in the modulation of sleep and circadian rhythms has led to the discovery of a novel class of melatonin agonists for treating insomnia, circadian rhythms, mood disorders, and cancer.

Real time adenosine fluctuations detected with fast-scan cyclic voltammetry in the rat striatum and motor cortex.

Background: Adenosine serves many functions within the CNS, including inhibitory and excitatory control of neurotransmission. The understanding of adenosine dynamics in the brain is of fundamental importance. The goal of the present study was to explore subsecond adenosine fluctuations in the rat brain in vivo.