Differential expression of NMDA receptors in serotonergic and/or GABAergic neurons in the midbrain periaqueductal gray of the mouse

Rutin antinociception involves opioidergic mechanism and descending modulation of ventrolateral periaqueductal grey matter in rats

“…The lack of effect of naltrexone on the antinociceptive action of rutin in phase I suggests that the flavonoid is acting through a non‐opioidergic mechanism. Various reports indicate that the GABAergic (Hahm et al., ), dopaminergic (Meyer et al., ), serotonergic (Monassi and Menescal‐de‐Oliveira, ), glutamatergic (Terashima et al., ), glycinergic (Choi et al., ) and adrenergic (Cui et al., ) systems may also participate in the reduction in nociception by activating the PAG. Alternatively, receptors like TRPA1, a member of the transient receptor potential (TRP) channel family of ion channels (subfamily A, member 1) expressed in a subset of nociceptive neurons, are activated after injecting formalin (McNamara et al., ).…”

Neuroplasticity of Supraspinal Structures Associated with Pathological Pain

“…Moreover, the upregulation of NR2B subunit expression in nonserotonergic/non‐GABAergic neurons was also reported after peripheral nerve ligation. These changes in the expression of NMDA receptor in PAG result in an alteration of the descending modulation of nociception, which might be an underlying mechanism for peripheral nerve injury‐evoked persistent pain (Terashima et al, ). Lastly, the protein expression of P2X3 receptors in the plasma membrane of the dorsolateral PAG of STZ‐treated rats decreased significantly.…”