The Texas A&M Battalion’s Homer Segovia observes that a bite of a jalepeño or habanero pepper can prove too hot to handle for some folks, resulting in frantic gulps of water and burning tears. However he reports that to a neuroscience lab at Texas A&M, these hot peppers can provide key insight into the neurological processes associated with pain.
Segovia reports that, a team of TAMU undergraduate and graduate students led by psychology professor Mary Meagher, PhD, at the Texas A&M Institute for Neuroscience are examining the way people sense and process pain, studying both the perception of and physiological responses to pain stimuli. To better understand these concepts, the lab applies capsaicin, or chili pepper extract, to the forearms of participants to induce pain.
Capsaicin, the active component of chili pepper and other plants belonging to the genus Capsicum, is a tasteless, odorless compound that is insoluble in water, consisting of seven closely related alkaloid or capsaicinoids — three of which are an irritant for mammals, including humans, producing a sensation of burning at the back of the palate and throat, and two others that cause the long, slow burn on the tongue or elsewhere, but no actual harm to tissue with which it comes into contact.
Capsaicin thus provides a way to study chronic pain without causing lasting injury or any tissue damage. It irritates the trigeminal pain receptor cells located throughout the mouth, the nose and the throat. When the body’s nerves sense the pain induced by the chemical on these cells, they immediately start to transmit pain messages to the brain, which receives these signals and responds by automatically releasing Endorphins (“endogenous morphine”), which are endogenous opioid peptides that function as neurotransmitters Endorphins are produced by the pituitary gland and the hypothalamus in vertebrates during exercise, excitement, pain, consumption of spicy food, love and orgasm, and resemble opiates in their abilities to produce analgesia and a feeling of well-being, creating temporary feeling of euphoria in some individuals, giving the chile pepper eater, a natural high.
“In order to understand the mechanisms that influence pain in healthy and pathological pain situations, we need to have laboratory studies,” Segovia cites Dr. Meagher commenting. “The reason we use the capsaicin model is it is a model that mimics many of the features and mechanisms that are engaged when somebody has what’s called chronic or pathological pain, but luckily it’s just short term.” With this study, Dr. Meagher’s lab intends to provide a greater understanding of the neurological processes associated with pain.
“If you can understand the mechanisms, both psychological and physiological, that are involved in determining how the ascending pain transmission gets amplified or what factors contribute to its inhibition, then we’ll understand various targets that we can go after pharmacologically and psychologically,” Dr. Meagher adds.
According to Dr. Mary Meagher’s TAMU faculty bio-page, her research focuses on the role of stress and emotion in health, with emphasis on pain and immune-related diseases. She examines, for example, the neurobiological mechanisms that underlie an animal model of multiple sclerosis, and her work has shown that stressful events can hasten the development of this neurological disease.
Dr. Meagher’s research is currently supported by the National Institute for Neurological Disorders and Stroke (NINDS), and additional support is provided by NSF and the National Multiple Sclerosis Society.
Dr. Meagher’s psychoneuroimmunology research program also examines how psychosocial stressors alter immune processes and vulnerability to an animal model of multiple sclerosis, Theiler’s murine encephalomyelitis virus infection. The program uses an integrative approach to study the interaction between behavioral, endocrine, and immune systems. Her recent work has shown that the adverse effects of chronic social stress are due to increases in interleukin-6, an inflammatory cytokine (a protein that helps regulate our body’s response to infection and injury) that has been linked to a range of chronic diseases including chronic pain and cancer.
The long-term goal of this research program is to elucidate mechanisms by which psychosocial stressors alter susceptibility to later infectious, inflammatory, and autoimmune diseases. Dr. Meagher’s research team also investigates how psychosocial stressors alter pain processing using animal and human laboratory models. Their most recent animal studies have shown that exposure to chronic social stress can exacerbate inflammatory pain states in mice. Similarly, their human laboratory pain studies have shown that exposure to noise stressors or a history of adverse childhood events can heighten acute inflammatory pain.
Animal models are also used to examine the neural systems that underlie affective pain modulation and the emotional component of pain. The long-term goal of this project is to develop parallel animal and human laboratory models to study the mechanisms by which psychosocial stressors contribute to pathological pain. In addition, Dr. Meagher collaborates with the MD Anderson Cancer Center in Houston to investigate the role of inflammatory cytokines in mediating fatigue and other behavioral disturbances induced by cancer and its treatment.
Homer Segovia’s The Battalion article cites TAMU senior university studies major, Carli Domenico, who led one of the Meagher lab’s capsaicin studies, noting that the research experience provided her with unique rewards as an undergraduate student, commenting that: “Undergraduate research is crucial across all fields of study because it provides for academic and personal development that nothing else on campus can offer. It teaches you to think and read critically and it exposes you to many more backgrounds than you would ever expect.”
The Texas A&M Institute for Neuroscience (TAMIN), is a multidisciplinary program created in 2009 between Texas A&M University (TAMU) and The Texas A&M University Health Science Center (TAMHSC), providing a unique environment for collaboration among scientists studying different areas of neuroscience in eight colleges (Agriculture, Architecture, Education, Engineering, Liberal Arts, Medicine, Science and Veterinary Medicine). The faculty of neuroscience (FNS) at TAMU/TAMHSC studies range from basic neuroscience to translational research aimed at developing therapies for neurological conditions including Alzheimer’s disease, ataxia telengiectasia, autism, cerebral palsy, depression, drug addiction, fetal alcohol syndrome, epilepsy, hereditary rat neuronal system degeneration, meningoencephalomyelitis, multiple sclerosis, neurofibromatosis, neuromuscular diseases, Parkinson’s disease, spinal cord injury, stress disorders and tumors of the nervous system.
The Texas A&M Battalion
The Texas A&M Institute for Neuroscience
The Texas A&M Institute for Neuroscience