TRPV1 and Anxiety: Starowicz et al. (2007) have first demonstrated a tonic endovanilloid facilitation of glutamate release within rats PAG, since 5′-iodoresiniferatoxin, a selective TRPV1 antagonist, facilitated nociceptive responses. In addition, authors have demonstrated that endovanilloids contribute to anxiety modulation. In this context, capsazepine (TRPV1 antagonist) injected into the PAG attenuated the defensive behavior of rats exposed to the elevated plus maze (Moreira et al., 2007).