Psychoneuroimmunology Flashcards
What is PNI?
The mechanisms whereby the nervous system and the immune system communicate with one another
Describe the direct connection between the CNS and the immune system
Innervation of primary and secondary lymphoid organs as well as the adrenal medulla
Describe the indirect connection between the CNS and the immune system
The CNS communicates hormonally with the immune system
Name 4 neurotransmitters/hormones that are activated by the CNS and affect the immune system
1) Catecholamines
2) GABA
3) ACh
4) Serotonin
These 4 chemicals are released by stress and lead to the release of CRH from the PVN of the hypothalamus
What is the general effect of cortisol on the immune system?
Most cells of the immune system are sensitive to cortisol and are inhibited in their function by this hormone
Bone marrow is primarily stimulated by what hormone?
NE
The thymus is stimulated by what chemicals?
NE, ACh and neuropeptides
The spleen is stimulated by what chemicals?
NE
Lymph Nodes are stimulated by what chemicals?
NE and neuropeptides
Describe how splanchnic nerves can affect the immune system
Stress –> stimulation of splanchnic nerves –> stimulation of adrenal medulla –> release of NE and E –> ACh release –> T-cells, B-cells, neutrophils, mononuclear cells and NK cells affected
What is the general effects of NE and Epi on the immune system?
NE and E increase leukocyte mobilization resulting in an increase in NK cells activity
What is the general effect of endorphins?
Endorphins, originate from POMC –> important role in analgesia (inability to feel pain) and feelings of happiness
What is the general role of enkephalins
Play a role in analgesia –> they can bind to the same opioid receptors as endorphins
How do endorphins and enkephalins affect the immune system?
Endorphins and enkephalins increase T cell and NK cell activity
Endorphins act more like hormones, whereas enkephalins act more like neurotransmitters
How does acute stress affect catecholamine levels?
Acute stress is associated with increased catecholamine levels
How is cortisol affected by acute stress?
Cortisol is increased and maintains higher levels for awhile
What happens to the number of lymphocytes in circulation in response to acute stress?
Initially they increases, but one hour later the various mononuclear cell populations decrease because the cells have localized to the regional lymph nodes
What causes immediate leukocyte mobilization in circulation in times of acute stress?
Catecholamines (Epi and NE release from the adrenal medulla)
What causes the leukocytes to redistribute to the lymph nodes where they can respond quickly to antigenic challenge?
Catecholamines and cortisol
-Cortisol mobilizes glucose/the ability to use muscles, and leukocytes are stored for later use should a challenge be presented
What is CD11a?
CD11a is an adhesion molecule on the surface of the leukocyte that binds to ICAM-1 for extravasation into the lymph nodes
How do moderate levels of cortisol affect the DTH response?
Moderate levels of acute cortisol enhance the DTH response (more cells in circulation lead to a greater response)
How do high levels of cortisol injected acutely affect the DTH response?
High levels of cortisol suppress the DTH response
How does chronic stress affect the DTH response?
Chronic stress ablates the DTH response completely
Compare the DTH response under conditions of acute vs chronic stress
Acute stress: enhance DTH
Chronic: ablated DTH
