Anxiogenic-like effect induced by TRPV1 receptor activation within the dorsal periaqueductal gray matter in mice

Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine

“…Capsaicin microinjected into the periaqueductal gray matter, a midbrain structure strongly implicated in anxiety, evoked anxiety-like behavior in mice subjected to the elevated maze test (Mascarenhas et al, 2013). So, what is the endovanilloid that regulates brain TRPV1?…”

Genotype-dependent responsivity to inflammatory pain: A role for TRPV1 in the periaqueductal grey

“…The DLPAG is known for its role in coordinating freezing, fight and flight behaviors in threatening situations, such as the presence of a predator (Mascarenhas et al, 2013).…”

Role of TRPV1 channels of the dorsal periaqueductal gray in the modulation of nociception and open elevated plus maze-induced antinociception in mice

“…Besides their role in pain modulation on peripheral primary afferents [13,14], TRPV1 channels have also been involved in the control of pain transmission in the central nervous system [1,2,7,15]. There is also evidence suggesting the participation of vanilloid receptors in brainstem areas involved in the modulation of defensive reactions [3,6] and on the descending pain inhibitory system [2,16,17] in which the midbrain periaqueductal gray matter (PAG) plays a crucial role (e.g. [18,19]).…”

“…Vanilloid type 1 channel (also known as transient receptor potential vanilloid type 1-TRPV1) is a nonselective cation channel that has been suggested to be involved in several neurobiological processes such as fear/anxiety, drug addiction and pain [1][2][3][4][5][6]. The role of TRPV1 in pain modulation has been shown through intracerebral injections of vanilloid compounds in animals exposed to various nociceptive tests (e.g., tail-flick and plantar tests [1,2,7]).…”

“…Due to its involvement in the modulation of fear/anxiety states [6,20,21], and in the descending modulation of nociception [19,22], midbrain PAG has also been implicated in an important phenomenon known as fear-induced antinociception, characterized as a decrease in the perception of pain when animals are confronted with innate or learned threatening situations (e.g. [23,24]; for an update review see [25]).…”