Antagonism of NPY-induced feeding by pretreatment with cyclic AMP response element binding protein antisense...

Although second messenger systems subserving neuropeptide Y (NPY)-mediated behaviors have been identified for a variety of receptors in several tissues, downstream signaling events are not well known. The nuclear binding protein, cyclic AMP response element binding protein (CREB) appears to be a transcription factor that is activated following injection of NPY into rat hypothalamus. To allow determination of the functional nature of CREB mediation of NPY-induced feeding, injection cannulae were implanted into the perifornical hypothalamus of 18 rats. Treatment of seven rats with CREB antisense oligonucleotide (15 ug) significantly antagonized NPY feeding for up to one week after treatment, while similar injections of CREB sense oligonucleotide (15 ug) had no significant effect on NPY-induced feeding. Two weeks after the antisense oligonucleotide treatment, feeding was once again elicited by the injection of NPY. Hypothalamic CREB protein was also reduced significantly two days after the CREB antisense oligonucleotide treatment. These results suggest that activation of CREB, probably through phosphorylation, may be a necessary event for the signal transduction of NPY stimulation into feeding behavior.