Tuberoinfundibular peptide of 39 residues produces anxiolytic and antidepressant actions.

Tuberoinfundibular peptide of 39 residues (TIP39) potently activates the parathyroid hormone-2 receptor (PTH2-R). A group of neurons in the posterior thalamus and one in the lateral pons synthesize TIP39. TIP39 projections reach most areas of PTH2-R density, including many within the limbic system and hypothalamus. We report that TIP39 induces Fos in the infralimbic cortex, lateral hypothalamus, preoptic area, lateral septum and paraventricular thalamic nucleus, areas believed to be important in anxiety and depression. TIP39 caused anxiolytic-like effects in the elevated plus-maze test and antidepressant-like effects in the forced-swim test. TIP39 did not change activity in the open field test. These findings point to a previously unknown role of the PTH2-R in the regulation of anxiety and depression.