Recent advances in the study of anesthesia-and analgesia-related mechanisms of S-ketamine

Abstract

Ketamine is a racemic mixture of equal amounts of R-ketamine and S-ketamine and is well known to anesthesiologists for its unique dissociative anesthetic properties. The pharmacological properties of ketamine, namely, its sympathetic excitation, mild respiratory depression, and potent analgesia, are still highly valued in its use as an anesthetic for some patients. In particular, since its advent, S-ketamine has been widely used as an anesthetic in many countries due to its increased affinity for NMDA receptors and its enhanced anesthetic and analgesic effects. However, the anesthetic and analgesic mechanisms of S-ketamine are not fully understood. In addition to antagonizing NMDA receptors, a variety of other receptors or channels may be involved, but there are no relevant mechanistic summaries in the literature. Therefore, the purpose of this paper is to review the mechanisms of action of S-ketamine on relevant receptors and systems in the body that result in its pharmacological properties, such as anesthesia and analgesia, with the aim of providing a reference for its clinical applications and research.

Nitric Oxide Donor Sodium Nitroprusside Reduces Racemic Ketamine─But Not Esketamine-Induced Pain Relief

“…The N -methyl- d -aspartate (NMDA) receptor antagonist ketamine produces a state of dissociative anesthesia at high dose and pain relief and mood improvement at subanesthetic doses. − Dissociative symptoms already occur at low ketamine doses, an effect that usually wanes when plasma concentrations drop but sometimes persist beyond the treatment period . We recently showed that the nitric oxide (NO) donor, sodium nitroprusside (SNP), reduced dissociative symptoms during the administration of racemic ketamine (which contains isomers R- and S-ketamine) but not during infusion of esketamine (which exclusively contains the S-isomer, S-ketamine) .…”