EXPRESSION OF AN OSCILLATING INTERFERON-GAMMA RECEPTOR IN THE SUPRACHIASMATIC NUCLEI

THE suprachiasmatic nuclei serve as the dominant circadian pacemaker i n the mammalian brain, regulating daily behavioral, physiological and hormonal rhythms. In the ventrolateral parts of these nuclei, the rece ptor for the key immunoregulatory molecule interferon-gamma (IFN-gamma ) was detected in the rat brain. The cellular localization of the IFN- gamma receptor corresponded to neuronal elements. Expression of the re ceptor followed a diurnal rhythm with a peak at zeitgeber time 15. Thi s peak coincided with an enhanced expression of janus kinase 1 and 2 a s well as the signal transducer and activator of transcription 1, whic h constitute the main intracellular signaling pathway of IFN-gamma. Th is is the first study to show expression of the receptor of an immune modulatory molecule in the pacemaker of the biological clock, which, t hus, may be influenced by immune system signal molecules. (C) 1998 Rap id Science Ltd.