Neuropathy literally means diseased nerves. There are several different reasons why people develop neuropathy. Neuropathy is quite often associated with diabetes, vitamin deficiencies, inflammation of the nerves, and toxins that poison the nerves. We have discussed many of the conditions that cause nerves to become diseased in patients in other articles. Patients with the signs and symptoms of neuropathy experience pain, burning, numbness, and other strange sensations known as paresthesias that usually begin in the feet and progress through the rest of the body. Pain and other symptoms can be debilitating and disabling regardless of the reason for the neuropathy.
The nervous system in higher animals like humans is a very complex collection of specialized cells known as neurons. Neurons have several unique characteristics, including a wire-like process known as an axon. The axon works much like an electrical wire, transmitting coded electrical signals known as nerve impulses throughout the body. Like a copper wire, the nerve axon has an insulation around it known as myelin. Unlike a copper wire, a nerve cell and its wire-like axon are living tissue. The neuron contains all the cellular machinery necessary to produce energy, maintain itself, and generate energy to support its function of transmitting and receiving electrical signals. Each neuron is an electrochemical marvel and is essentially a living battery. This amazing communication network occurs at the microscopic level and consumes incredible amounts of energy to function properly.
The myelin insulation that surrounds the nerve axon is also living tissue, and the nerve cell and its myelin cell companions are intimately arranged to maintain and support each other.
The nervous system generally does a remarkable job of sending and receiving training from various parts of the body and acts as a sensor system to monitor what is happening in the body and also as an effector system that drives necessary changes in the body based on the input of the sensors.
Due to its complexity, the nervous system and the myelin cells that support it are vulnerable to the slightest alteration of metabolism. Axons are like a microscopic web, but they travel great distances within the body. They can be very easily deregulated by trauma or compression.
Think of the nervous system as a living, delicate, and vulnerable communications network that consumes extraordinary amounts of energy for proper operation and maintenance. It is no wonder that the nervous system is susceptible to injury, disease, metabolic abnormalities, immune problems, and many other afflictions that can make it ill and cause it to malfunction.
Peripheral nervous system malfunction occurs frequently and when this happens, people develop the cardinal symptoms of polyneuropathy.
Although polyneuropathy is one of the most common diseases of the peripheral nervous system, there are few FDA-approved medications available to treat it. Many patients who try traditional prescription drugs to alleviate their neuropathy symptoms are disappointed with the results.
Too often, newer investigational drugs look promising, but fail due to unwanted side effects. Research and data obtained from failed drug development experiments can sometimes be applied to herbal medicine, where natural substances can work in a similar way to artificial chemicals, but with less severe side effects. The scientific study of natural substances that can mimic artificial drugs is known as pharmacognosy. When this knowledge is applied to the nervous system we call it Neuropharmacognosia. You can translate this as the study of the pharmacology of natural substances that can influence the function of the nervous system. There are a number of natural substances that can mimic the pharmacology of medications used to treat neuropathy. We have discussed them in other articles, but we will review them together here.
Based on experimental data on nerve function and disease, a number of broad classes of chemicals may have a theoretical application in alleviating the symptoms of neuropathy.
When nerves become diseased, the production of a chemical known as GABA can calm irritable and inflamed nerves and provide relief for people struggling with the symptoms of neuropathy. You can think of GABA as a brake pedal that slows down the symptoms of neuropathy. There is research to suggest that the herbs Valerian Root and Lemon Balm may increase GABA, thereby applying the body’s brake on nerve drain pain. Valerian root can block an enzyme known as GABA-T that breaks down and neutralizes GABA in the nervous system. By blocking the breakdown of GABA, valerian root can prolong the braking effect of GABA on the nerve and slow down the symptoms of neuropathy. Lemon balm seems to increase the effect of GABA in a slightly different way. Instead of blocking the breakdown of GABA, lemon balm can stimulate an enzyme known as GAD that is responsible for the formation of GABA. So, the braking action of GABA on the diseased nerve is supported by increased production of this neurotransmitter.
If GABA acts as the body’s brake on an uncontrolled nervous system, glutamate is the nerve accelerator. Studies suggest that injured nerves become hypersensitive because glutamate is released after the nervous system becomes irritated. This has the effect of sensitizing the nerve and contributing to the signs and symptoms of neuropathy. There are two potentially important herbs that can block the effects of glutamate on the nervous system in neuropathy. The first is theanine, a protein derived from green tea. Theanine is believed to act as a glutamate analog. This means that theanine is processed by the body like glutamate, but it does not have the nerve-stimulating effects of glutamate. Think of theanine as a blank bullet that has the net effect of reducing the actions of glutamate. The other herb that can reduce the excitatory effects of glutamate is magnolia bark. Magnolia bark is believed to bind to and block a specific glutamate receptor. This suggests that Magnolia Bark is a specific glutamate antagonist and could be a more specific way of taking your foot off the gas on nerves damaged by neuropathy.
In keeping with our car analogy, if GABA is the nerve brake in neuropathy and glutamate acts like the gas pedal, you might think that a third chemical known as glycine is transmission. Glycine slows down the nervous system. Think about slowing down your nerves. Glycine displaces the nerve in neuropathy directly, slowing down and inhibiting the painful transmission of nerve signals, but it can also indirectly compete with glutamate. The mechanism by which glycine might bring relief to patients with neuropathy is a little less straightforward. If a patient took a large dose of glycine, the nerves would slow down. However, this effect would not last long, because in the nervous system, glycine is removed from the nerve by what is known as a glycine transporter. The glycine transporter has the net effect of getting rid of the glycine, effectively causing the nervous system to rev up again. This glycine transporter system is so effective that it makes glycine an impractical neuropathy treatment. Due to the glycine transporter, the nerve simply cannot retain enough glycine in the nerve to slow down the function of a hypersensitive nerve significantly. However, there are substances that can inhibit the glycine transporter and this appears to be a promising way to improve the suppression of nerve hyperexcitability, as occurs in neuropathy. The herb Prickly Ash Bark appears to be a major glycine transporter inhibitor. Prickly Ash has a long history of use for pain relief. Also, the naturally occurring compound sarcosine is a known glycine transporter inhibitor. Both naturally occurring substances appear to be candidates for the relief of the signs and symptoms of neuropathy.
Another avenue that can be exploited for neuropathy relief is the endogenous cannabinoid receptor system. This system is activated by marijuana and is believed to suppress pain at the highest levels of the nervous system. Receptors in the endogenous cannabinoid system can be activated to relieve pain without producing a “high” and the side effects associated with marijuana use from certain fatty acid breakdown products in the nervous system. Substances that block the enzyme fatty acid amide hydrolase or FAAH appear to activate the endogenous cannabinoid system and are currently being investigated for the treatment of neuropathic pain. There appear to be naturally occurring FAAH inhibitors in red clover and the herb MACA. This suggests that these herbs, through their potential to modulate FAAH enzyme activity, may be able to activate the endogenous cannabinoid system and provide neuropathic pain relief.
Finally, with particular reference to neuropathy associated with diabetes, protein kinase C or the enzyme PKC and their relationship to T-type calcium channels may be therapeutic targets. It appears that high blood glucose deregulates PKC in diabetic nerves. PKC appears to drive specific calcium channels in diabetic nerves known as T-type calcium channels. These changes are believed to cause hypersensitivity and excitability at least in the nerves affected by diabetic neuropathy.
Chelidonium Majus is a herbal remedy that can modulate PKC. The alkaloid chelerythrine found in this herb is a potent antagonist of protein kinase C. This suggests a possible benefit of this herb in polyneuropathy. Although generally safe, some reports of Chelidonium Majus-associated liver toxicity appear in the medical literature.
Picrorhiza Kurroa is an herb that contains the phytochemical Apocynin. At least one study suggests that apocynin prevented or markedly reduced upregulation of T-type calcium channels Cav3.1 and Cav3.2. This suggests that Picrorhiza Kurroa may be able to down-regulate the overexpression of T-type calcium channels Cav3.2 that are believed to contribute to the hyperexcitability of nerves seen in diabetic neuropathy.
A final note and warning about using information from the Internet to try to treat a medical condition. Do not do it! The use of this article is provided solely for patients to discuss the information contained therein with their authorized healthcare provider. Herbal treatments, while generally safe, can have unwanted or unpredictable side effects. Only a licensed physician who is familiar with your specific medical condition can safely diagnose and advise you on treatment for your particular condition. Always consult and inform your physician before making additions or changes to your treatment regimen.