Description of PSYCHOTROPIC ANALGESIC NITROUS OXIDE for investigating the endorphin system in man  


Psychotropic analgesic nitrous oxide (PAN) is a mixture of high concentrations of oxygen with relatively low concentrations of nitrous oxide (N2O or laughing gas). SABRI investigators introduced the term PAN to clearly distinguish those concentrations of the gas which produce psychotropic effects while the subject is fully conscious. This distinction is of some practical importance because nitrous oxide is most commonly used for, and therefore associated with anaesthesia and unconsciousness. Nitrous oxide has been known since the late 18th century and was the first anaesthetic gas ever used. It has been employed ever since, mainly at anaesthetic concentrations, and is still probably the most commonly used of all anaesthetic agents. In modern anaesthetic practice it is combined with other more powerful agents.

Over the last 30 or so years, it has been used, mainly in dentistry, for its analgesic rather than anaesthetic properties. When administered at analgesic concentrations, the subject is always conscious, which avoids the necessity of observing the precautions usually associated with anaesthesia. At these low concentrations nitrous oxide interacts with the endorphin system in man and produces it psychotropic effects. Because it is administered as a gas, it is absorbed through the lungs and reaches the brain within seconds, almost as rapidly producing observable changes. On the other hand, if it is discontinued, it is as quickly eliminated from the body. As a result of its rapid onset and offset of action and its effects on the endorphin system it allows the investigator to fine-tune the endorphin system in humans in both health and disease. This has given SABRI scientists a considerable advantage over other investigators in researching brain function directly in man, and permits almost complete avoidance of animal experiments.

The gases are administered with dental equipment (Matrx Medical or similar commercially available dental analgesia machine), which ensures that at least 30% oxygen is delivered to the patient. Should the flow of oxygen ever fall below 30% the nitrous oxide is instantly switched off by a fail-safe device, thus preventing anaesthesia or the possibility of delivering a mixture without a safe level of oxygen.

The system is an open one in that the subject breathes through a nasal mask, and the mouth is therefore uncovered. The nasal mask thus prevents inadequate amounts of oxygen reaching the patient as well as guarding against producing unconsciousness.

The PAN technique for investigating the endorphin system in man offers a number of important advantages.

Note: The endorphin system, found in the brain and when stimulated, mimics the effects of substances such as morphine. It is involved in many functions, including mood, pain and pleasure. It was discovered between 1972-1975.