How Laughing Gas or Nitrous Oxide Works

What Laughing Gas Does in the Body

Laughing gas reduces pain and anxiety by binding to a host of receptors in the brain.
Laughing gas reduces pain and anxiety by binding to a host of receptors in the brain. Andersen Ross, Getty Images

Laughing gas or nitrous oxide is used in the dentist's office to reduce patient anxiety and relieve pain. It's also a common recreational drug. Have you ever wondered how laughing gas works? Here's a look at how laughing gas reacts in the body and whether it's safe or not.

What Is Laughing Gas?

Laughing gas is the common name for nitrous oxide or N2O. It is also known as nitrous, nitro, or NOS. It's a nonflammable, colorless gas that has a slightly sweet flavor and odor.

In addition to its use in rockets and to boost engine performance for motor racing, laughing gas has several medical applications. It has been used in dentistry and surgery as an analgesic and anesthetic since 1844, when dentist Dr. Horace Wells used it on himself during a tooth extraction. Since that time, its used has become commonplace in medicine, plus the euphoric effect from inhaling the gas has led to use as a recreation drug.

How Laughing Gas Works

Although the gas has been used for a long time, the exact mechanism of its action in the body is incompletely understood, in part because the various effects depend upon different reactions. In general, nitrous oxide moderates several ligand-gated ion channels. Specifically, the mechanisms for the effects are:

  • Anxiolytic or Anti-Anxiety Effect
    Studies indicate the anti-anxiety effect from inhalation of laughing gas derives from increased activity of GABAA receptors. The GABAA receptor acts as the central nervous system's principal inhibitory neurotransmitter
  • Painkiller or Analgesic Effect
    Laughing gas reduces the perception of pain by facilitating an interaction between the descending noradrenergic system and the endogenous opioid system. Nitrous oxide causes the release of endogenous opioids, but how this happens is unknown.
  • Euphoria Effect
    Nitrous produces euphoria by causing dopamine to be released, which stimulates the mesolimbic reward pathway in the brain. This contributes to the analgesic effect, too.
     

    Is Nitrous Oxide Safe?

    When you get laughing gas at the dentist's or doctor's office, it's very safe. A mask is used to first administer pure oxygen and then a mixture of oxygen and laughing gas. The effects on vision, hearing, manual dexterity, and mental performance are temporary. Nitrous oxide has both neurotoxic and neuroprotective effects, but limited exposure to the chemical tends not to cause a permanent effect, one way or the other.

    The primary risks from laughing gas is from inhaling a compressed gas directly from its canister, which could cause severe lung damage or death. Without supplemental oxygen, inhaling nitrous oxide can cause hypoxia or oxygen deprivation effects, including lightheadedness, fainting, low blood pressure, and potentially a heart attack. These risks are comparable to those of inhaling helium gas.

    Prolonged or repeated exposure to laughing gas can lead to a vitamin B deficiency, reproductive problems in pregnant women, and numbness. Because very little nitrous oxide is absorbed by the body, a person inhaling laughing gas breathes out most of it. This can lead to risks to medical personnel who routinely use the gas in their practice.