| First Author | Mascarenhas DC | Year | 2013 |
| Journal | Behav Brain Res | Volume | 250 |
| Pages | 308-15 | PubMed ID | 23707246 |
| Mgi Jnum | J:198996 | Mgi Id | MGI:5500094 |
| Doi | 10.1016/j.bbr.2013.05.023 | Citation | Mascarenhas DC, et al. (2013) Anxiogenic-like effect induced by TRPV1 receptor activation within the dorsal periaqueductal gray matter in mice. Behav Brain Res 250:308-15 |
| abstractText | Pharmacological manipulation of TRPV1 (Transient Receptor Potential Vanilloid type-1) receptors has been emerging as a novel target in the investigation of anxiety states. Here, we attempt to show the role played by the TRPV1 receptors within the dorsal periaqueductal gray matter (dPAG), a midbrain structure strongly involved in the modulation of anxiety. Anxiety was assessed by recording spatiotemporal [percent open arm entries (%OE) and percent open arm time (%OT)] and ethological [e.g., head dipping (HD), stretched-attend postures (SAP)] measures in mice exposed to the elevated plus-maze (EPM). Mice received an intra-dPAG injection of the TRPV1 agonist capsaicin (0, 0.01, 0.1 or 1.0nmol/0.2muL; Experiment 1) or antagonist capsazepine (0, 10, 30 or 60nmol/0.2muL; Experiment 2), or combined injections of capsazepine (30nmol) and capsaicin (1.0nmol) (Experiment 3), and were exposed to the EPM to record spatiotemporal and ethological measures. While capsaicin produced an anxiogenic-like effect (it reduced %OE and %OT and frequency of SAP and HD in the open arms), capsazepine did not change any behavior in the EPM. However, when injected before capsaicin (1.0nmol), intra-dPAG capsazepine (30nmol-a dose devoid of intrinsic effects) antagonized completely the anxiogenic-like effect of the TRPV1 agonist. These results suggest that the anxiogenic-like effect produced by capsaicin is primarily due to TRPV1 activation within the dPAG in mice, but that dPAG TRPV1 receptors do not exert a tonic control over defensive behavior in mice exposed to the EPM. |
