In a major breakthrough, German scientists have pinpointed the cause of the loss of the sense of smell in both humans and mice and linked it to the ability to feel pain. The researchers, led by Frank Zufall, PhD University of Saarland School of Medicine in Homburg, wrote in the June 2012 online issue of the Archives of Neurology that these findings "are of special clinical relevance" because the culprit, a sodium channel encoded by the gene SCN9A, is well-known for its essential role in the perception of pain. "Therefore, this channel is being explored as a promising target in the search for novel analgesics," the authors stated.
They further reported that their finding "offers a functional understanding of a monogenic human disorder that is characterized by a loss of 2 major senses—nociception [perception of pain] and smell—thus providing an unexpected mechanistic link between these 2 sensory modalities." They also wrote that the Nav1.7 channel "is currently being explored as a promising target for the pharmacotherapy of pain in humans. We wait with interest to see whether pharmacological blockade of this channel in vivo will also affect our sense of smell."
Worth noting here is that partial or complete loss of the sense of smell, which can happen with age and with neural problems including cognitive decline, limits a person's ability to fully taste food. This may lead to malnutrition and mood disorders. If you find that your sense of smell is diminishing, particularly if you're over age 60, talk to your healthcare team about strategies you can use to prevent slipping into poor eating habits and depression.
