As promised in my last post, let’s take a close look at the sympathetic nervous system (SNS). Neurotransmitters called peptides enable communication between the mind and the body through the SNS. The sympathetic-adrenal-medullary pathway activates the autonomic nervous system using these neurotransmitters and neuropeptides for direct communication with immune cells. Three neurotransmitters – norepinephrine, serotonin, and dopamine – are essential for neural communication.

Neurotransmitters attach to immune cells and affect their ability to multiply or destroy cells. According to research by Freeman and Lawlis, it is likely that the emotions resulting from stressors increase susceptibility to disease (because the brain releases neurotransmitters during times of stress.) ( Freeman & Lawlis, 2001)

They further report that neuropeptides, secreted by the brain and immune system, have a crucial role in mind-body interactions since immune cells carry receptors for all the neuropeptides. The limbic system, the part of the brain that regulates emotions, is particularly rich in receptor sites for neuropeptides. Thus, it is reasoned that neuropeptides are a significant factor involved in the effects of the mind on immunity. (  Freeman & Lawlis, 2001)

Neurotransmitters that were once thought found only in the brain have been also located in the immune system. Therefore, any immune function can occur in the brain or anywhere in the immune system. When the central nervous system receives cognitive stimuli, it conveys that information through hormonal pathways to receptors on immune cells such as macrophages.