Scientific reports
June 27, 2019
Jon G Dean, Tiecheng Liu, Sean Huff et al.
111 citations
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.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
June 1, 2024
Lora Khatib, Jon G Dean, Valeria Oliva et al.
9 citations
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.
Anesthesia and analgesia
June 1, 2022
Michael A Brito, Duan Li, Christopher W Fields et al.
Cortical acetylcholine levels correlate with neurophysiologic complexity and frontoparietal connectivity during altered states of consciousness. In rats under isoflurane anesthesia, subanesthetic ketamine (10 mg/kg/h) produced sustained increases in brain complexity and high gamma connectivity, accompanied by progressive rises in prefrontal (104%) and parietal (159%) acetylcholine. Nitrous oxide caused a transient increase in complexity and connectivity with smaller acetylcholine increases (prefrontal 56%, parietal 43%), followed by a later phase of decreased acetylcholine, reduced complexity, and weaker connectivity. These findings link cortical acetylcholine to changes in consciousness level.