抄録
Urocortin II (UCN II) is a newly identified peptide that belongs to the corticotropin releasing factor (CRF) family, and acts as a feeding suppressant via CRF 2 receptors (CRF2-Rs). The ventromedial nucleus of the hypothalamus (VMH) is known as a satiety center in the brain and expresses abundant CRF2-Rs. However, the actions of UCN II on VMH neurons are remained unclear. Thus, we examined the effects of UCN II on VMH neurons using brain slice preparations and extracellular and whole cell patch clamp recording techiniques. In extracellular recording, bath-application of UCN II excited about 60% of VMH neurons recorded, and the excitation was dose-dependent and persisted in the Low Ca2+-high Mg2+ ACSF. Pretreatment with antisauvagine-30 (aSVG-30), a selective antagonist for CRF2-R, abolished the excitation induced by UCN II. In whole cell patch clamp recording, the membrane resistance decreased during the UCN II-induced depolarization. When the current-voltage relationship was measured in voltage clamp mode, the reversal potential was about -48 mV, suggesting an involvement of non-selective cation channels in UCN II-induced depolarization. These results suggest a possibility that UCN II participates in the feeding suppression through the excitaion of VMH neurons. [J Physiol Sci. 2008;58 Suppl:S94]
