摘要: Several gaseous molecules, including nitric oxide and carbon monoxide (CO), are important neurotransmitters. In their Perspective, [Boehning Snyder][1] comment on new work ([Dioum][2] et al .) that reveals another activity for CO, of modulator the transcription factor NPAS2, a crucial component circadian clock. [1]: http://www.sciencemag.org/cgi/content/full/298/5602/2339 [2]: http://www.sciencemag.org/cgi/content/short/298/5602/2385