Burning copal incense from Protium copal, traditionally used by the Maya, reduced anxiety-like behavior in rats in social interaction and conditioned emotional response tests, but not in the elevated plus maze. The effect depended on time and was blocked by antagonists of GABAergic and endocannabinoid systems, indicating both systems are involved. The resin and incense contained high levels of α- and β-amyrins and inhibited monoacylglycerol lipase activity in vitro. This suggests the anxiolytic effects may be mediated through benzodiazepine receptors and the endocannabinoid system.
In mechanically ventilated patients with ARDS, esketamine combined with midazolam improved respiratory system compliance and oxygenation compared with remifentanil combined with midazolam. At 72 hours after medication, static compliance was higher in the esketamine group (49.8 ± 13.8) than in the control group (42.4 ± 11.9), while plateau pressure and peak airway pressure were lower. Both groups received equivalent sedation and analgesia. The findings suggest esketamine may offer respiratory advantages in this population.