INTERACTIONS BETWEEN CYTOKINES AND NITRIC-OXIDE

There is now an impressive range of evidence supporting the important role of cytokines in sleep regulation (see Krueger et al., 1995; De Si moni et al., 1995). It has also been reported that inhibition of nitri c oxide (NO) synthesis suppresses sleep in rabbits (Kapas et al., 1994 ). This is not surprising, since NO is closely involved in neurotransm ission (Garthwaite, 1991; Schuman and Madison, 1994) and cytokines are the major inducers of NO synthesis (Hibbs et al., 1990). Further, it is now clear that NO plays an important role in modulating immune resp onses, possibly through the differential regulation of cytokine synthe sis (Taylor-Robinson et al., 1994). In this article, I will provide ev idence for the interactions between cytokines and nitric oxide, and di scuss their implications in the regulation of immune responses. I shal l illustrate these mainly with results from my coworkers and I, from o ur laboratory rather than attempting an exhaustive review of the subje ct.