The newly discovered multi-oscillatory nature of the mammalian circadian clock system and the cloning of the genes involved in the molecular mechanism that generates circadian rhythmicity have opened new approaches for understanding how mammals are temporally organized and how the mammalian circadian system reacts to the lack of normal synchronization cues. In the present study we investigated ...

Arylalkylamine N-acetyltransferase controls daily changes in melatonin production by the pineal gland and thereby plays a unique role in biological timing in vertebrates. Arylalkylamine N-acetyltransferase is also expressed in the retina, where it may play other roles in addition to signaling, including neurotransmission and detoxification. Large changes in activity reflect cyclic 3',5'-adenosi...

Nocturnal melatonin production is reportedly controlled by the rhythms of serotonin N-acetyltransferase (NAT, or arylalkylamine N-acetyltransferase). While analyzing the melatonin synthetic pathways of Long Evans cinnamon (LEC) rats mutant for PINA, a pineal night-specific ATPase defective in Wilson disease, we discovered that NAT activity and protein levels are greatly reduced in LEC rats, and...

This study was to investigate the circadian rhythms and light responses of Clock gene and arylalkylamine N-acetyltransferase (NAT) gene expressions in the rat pineal gland under the 12 h-light : 12 h-dark cycle condition (LD) and constant darkness (DD). Sprague-Dawley rats housed under the light regime of LD (n=36) for 4 weeks and of DD (n=36) for 8 weeks were sampled for the pineal gland once ...

Amine N-acetylation in the pineal gland is of special importance because it is the first step in the synthesis of melatonin from serotonin. In the present study the N-acetylation of arylamines and arylalkylamines by homogenates of rat and sheep pineal glands was investigated. The arylamines studied were p-phenetidine and aniline; the arylalkylamines studied were tryptamine, serotonin, 5-methoxy...

The evolution of N-acetyltransfeases (NATs) seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT) has been extensively studied since it leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with inverteb...

Introduction Melatonin (N-acetyl-5-methoxytryptamine) is synthesized from tryptophan and it is a neurohormone which is secreted from the pineal gland of all mammals [1, 2]. Tryptophan, which is a melatonin precursor, is hydroxylated in the cells and turned into 5-hydroxytryptophan. Then this is decarboxylated and turned into serotonin (5-hydroxytryptamine). Serotonin is acetylated by arylalkyla...