Circadian rhythm in NO synthase I transcript expression and its photoperiodic regulation in the rat pineal gland.
The photoneural regulation of nitric oxide synthase type I (NOS I) expression in the rat pineal was investigated using semiquantitative RT-PCR. NOS I transcript expression exhibited a daily rhythm with peak values during the night hours. The daily rhythm in NOS I transcript expression persisted under constant dark conditions and was abolished under constant light conditions. The extent of nocturnal NOS I expression was found to be dependent on the photoperiod. It was attenuated under 20 h light and 4 h dark (L:D 20:4) compared with 12 h light and 12 h dark (L:D 12:12). The present findings indicate that, in the rat pineal, NOS I transcript expression exhibits a true circadian rhythm. Further, photoperiod-induced changes in circadian transcript expression appear to be responsible for reported changes in NOS I protein expression.
Department of Anatomy, Johannes Gutenberg University, Mainz, Germany.
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D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000235:genetics; D002940:Circadian Rhythm / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052248:Nitric Oxide Synthase Type I; D017440:Photoperiod; D010870:Pineal Gland / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D012333:RNA, Messenger; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D001191:Arylamine N-Acetyltransferase