[Cascade of biochemical events triggered by stimulation of adrenergic receptors in the rat pineal gland--from cell membrane to nucleus].
Pineal glands of various vertebrate species synthesize melatonin in a circadian rhythm generated by an endogenous pacemaker. The levels of melatonin and activity of serotonin N-acetyltransferase (AA-NAT: a penultimate and key regulatory enzyme in melatonin biosynthesis) are low during the light phase and high during the dark phase of any natural or imposed light-dark illumination cycle. The expression of AA-NAT gene in rat pineal gland is regulated by a photoneural system that acts through the adrenergic-cAMP-related mechanisms in pinealocytes. Concomitant stimulation by noradrenaline of beta 1- and alpha 1-adrenergic receptors, in a mechanism of "AND gate" activation, results in a large, 60-100-fold increase in intrapinealocyte cAMP level. The role of cAMP-dependent transcription factors CREB, ICER and Fra-2 in turning on and off the AA-NAT gene expression is discussed.
Zawilska
J B
JB
Zakład Amin Biogennych, Polskiej Akademii Nauk w Lodzi.
Rosiak
J
J
Nowak
J Z
JZ
D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D015870:Gene Expression; D008550:Melatonin / Q000096:biosynthesis; D009638:Norepinephrine / Q000502:physiology; D010870:Pineal Gland / Q000378:metabolism*; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D014157:Transcription Factors / Q000502:physiology
D011941:Receptors, Adrenergic; D014157:Transcription Factors; D000242:Cyclic AMP; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin; D009638:Norepinephrine