Neurobiological Mechanisms of Acupuncture for Some Common Illnesses: A Clinician's Perspective

Acupuncture, an ancient practice consisting of the insertion of needles at specific points on the body for therapeutic purposes, has gained increasing acceptance in Western medicine, especially for the treatment of musculoskeletal conditions such as back pain. Although the traditional Chinese concepts of qi (氣), meridians, and yin-yang (陰陽) have historical value, many Western medical professionals and patients find it difficult to understand these ancient concepts. To facilitate the incorporation of acupuncture into conventional medical practice, it becomes essential to explain its mechanisms of action using contemporary knowledge of neurobiology and physiology. The basic phenomenon of acupuncture can be understood simply: the insertion of needles at certain locations in the body produces specific therapeutic effects, regardless of the theoretical explanations used to describe it.

This scientific study aimed to present the neurobiological mechanisms proposed to explain how acupuncture works in different common clinical conditions, using a Western medical perspective. The researcher analyzed available scientific evidence on the effects of acupuncture in various medical conditions, organizing the mechanisms of action into three main categories: local effects, somato-autonomic reflexes, and systemic effects through brain neurotransmitters. The methodology consisted of a narrative review of the existing scientific literature, examining studies that investigated the neurobiological foundations of acupuncture across different clinical applications. The author also explored alternative approaches to understanding the mechanisms of acupuncture, including the fascia network (connective tissue) and the primo vascular system, and discussed the implications of these findings for the design of clinical trials.

The findings revealed that acupuncture acts through multiple well-grounded neurobiological mechanisms. For musculoskeletal conditions, the main mechanism involves tissue microinjuries that stimulate increased local blood flow, facilitate healing, and promote analgesia through the release of neurotransmitters such as enkephalin. An important milestone was the discovery that acupuncture stimulates the release of endogenous endorphins, establishing the neural model of action. For effects on internal organs, acupuncture works through somato-autonomic reflexes, in which stimulation of specific muscles sends signals to the brain that then project to autonomic nerves, affecting functions such as digestion and blood pressure.

In the treatment of conditions such as smoking cessation and depression, acupuncture modifies levels of brain neurotransmitters such as serotonin and dopamine in the limbic system, altering emotional states and reducing cravings. For headache, acupuncture affects pain-modulating neurotransmitters such as substance P and met-enkephalin along nociceptive pathways. In hormonal conditions such as polycystic ovary syndrome, acupuncture influences the hypothalamic-pituitary axis, reducing luteinizing hormone release.

For patients, these findings mean that acupuncture has solid scientific foundations and can be considered a legitimate modality of conventional medicine, not merely a mystical alternative practice. The neurobiological mechanisms explain why acupuncture is especially effective for musculoskeletal pain, where it has the most compelling evidence of efficacy. For health professionals, understanding these mechanisms allows for a more rational practice of acupuncture, based on scientific evidence rather than traditional concepts. An important clinical implication is that, for musculoskeletal conditions, there is no point specificity — that is, any site where pain is present may be effective for treatment, which explains why "sham points" used in clinical trials often show some efficacy.

On the other hand, for systemic effects involving the brain, some point specificity exists, although not as rigid as traditionally described. This has important implications for the design of clinical research in acupuncture.

The study acknowledges several important limitations. Many of the proposed mechanisms were established primarily in animal studies and require further clinical validation in humans. Evidence of efficacy varies considerably across different clinical applications — while it is strong for musculoskeletal pain and nausea, it is still inconclusive for conditions such as smoking cessation, headache, and hypertension. The author acknowledges that there is no unified theory of the mechanisms of acupuncture, only varied models and hypotheses for different clinical applications.

In addition, some fundamental aspects, such as why certain traditional points are more effective than others located over the same deep nerves, remain poorly understood. The study concludes that, although current neurobiological models are rudimentary and may later be modified or replaced, they represent an important advance in the scientific understanding of acupuncture. This evidence-based approach allows acupuncture to be viewed as a modality of conventional medicine, facilitating its acceptance and integration into Western medical practice.