The psychedelic compound N,N-dimethyltryptamine (DMT) is produced naturally in mammals, but whether it is made in the brain was unclear. This study found that the enzymes needed to synthesize DMT are present in the cerebral cortex, pineal gland, and choroid plexus of both rats and humans. In rat brain tissues, the two key enzymes were found together, unlike in peripheral tissues. DMT concentrations in the cerebral cortex of behaving rats were similar to those of neurotransmitters like serotonin. DMT levels in the visual cortex rose significantly after cardiac arrest, even without the pineal gland. These findings indicate the rat brain can synthesize and release DMT at neurotransmitter-like levels, suggesting human brains might do the same.
Mindfulness meditation directly reduces evoked chronic low back pain through non-opioidergic processes, not by activating the body's opioid system. In a double-blind, randomized, placebo-controlled trial with a drug crossover design, 59 individuals with chronic low back pain completed a four-session mindfulness or sham mindfulness-meditation intervention. During intravenous naloxone (an opioid blocker) or saline infusion, both mindfulness and sham mindfulness groups showed significant pain reductions during meditation compared to rest. However, the mindfulness group reported significantly lower pain than the sham group, and its effects were more pronounced, suggesting unique benefits from non-reactive appraisal processes. Pain severity and interference scores also decreased.