Chronic pain affects some 86 million Americans a year, and is the cause of business and industry loses about $90 billion annually to sick time, reduced productivity, and direct medical and other benefit costs. Many who suffer from chronic pain are told to learn to “live with it.” Now new research indicates that relief could be provided in the vitamin counter at the neighborhood grocery story.
B-vitamins, such as thiamin (B1), pyridoxine (B6), and cyanocobalamin (B12), have been proven to be clinically effective in treating various painful conditions such as lumbago, sciatica, trigeminal neuralgia, facial paralysis and optic neuritis as acting as an analgesia (pain reliever). Past research has explored the analgesic and anti-inflammatory effects of vitamin B1, B6 and B12. For example, vitamin B1, B6, and B12 and combinations inhibited chemical- and heat-induced pain evidenced by writhing test, heat coil test, or hot plate test (although some negative results have also been reported).
Nociceptive pain comes from sprains, bone fractures, burns, bumps, bruises, inflammation (from an infection or arthritic disorder), obstructions, and myofascial pain (which may indicate abnormal muscle stresses). The pain originates from the nociceptors, nerves which sense and respond to parts of the body which suffer from damage. They signal tissue irritation, impending injury, or actual injury. When activated, they transmit pain signals (via the peripheral nerves as well as the spinal cord) to the brain. One of the research studies found that noxious heat evoked nociceptive responses of spinal dorsal horn neurons were suppressed by compound of B1, B6 and B12. These studies indicate that the B-vitamins possess the capability to block physical distress in some painful conditions.
Recently, several animal models of painful sequelae in humans after the primary sensory neurons injury have been developed such as the model of chronic compression of dorsal root ganglion (DRG). However, this antinociceptive efficacy of B-vitamins has not been evaluated in animals with neuropathic pain, that is result of an injury or malfunction in the peripheral or central nervous system. The pain is often triggered by an injury, but this injury may or may not involve actual damage to the nervous system.
Researchers recently found that intraperitoneal (i.p.)- or intrathecal (i.t.)- injection of B1, B6 and B12 or their combination significantly reduced thermal hyperalgesia in CCD rats. On the other hand, mechanisms underlying the B-vitamins-induced analgesia remain unknown. It has been reported that B complex vitamins can activate potently the soluble guanylyl cyclase (sGC), and cyclase guanosine monophosphate (cGMP) in a wide variety of tissues. cGMP plays an antinociceptive activity in nociceptive processing. Others have suggested that B1 could produce antinociception by the activation of GC mediated by cGMP in p-benzoquinone-induced mouse writhing model.