1. Stress and Health (and the brain) Is stress a good thing?

2. Fields of interest Behavioral medicine Psychoneuroimmunology

3. Stress What is it? –stress is the nonspecific response of the body to any demand placed on it What are some of the variables that contribute to how we respond to stress?

4. Psychosomatic Illnesses real illnesses that are exacerbated by stress- –these can be potentially life threatening

5. Psychosomatic Illnesses ulcers heart disease asthma various skin conditions -

6. (hypothalamus) Overactivation of either system can have negative consequences

7. Two systems activated during stress and emotion 1. Sympathetic Nervous system –activates adrenal glands to release E, NE, and other catecholamines into blood

10. Are there consequences of repeated sympathetic activation? perhaps………

11. increased hypertension in high stress jobs

12. As a side note – sympathetic activation is also an indicator of arousal Physiological measures of arousal lie detector tests –what do they measure –problems with these tests

13. 2. HPA Axis - (hypothalamic-pituitary- adrenal) axis causes the release of “stress” hormones (corticosteroids) cortisol - in humans corticosterone - in rats

14. Hypothalamus releases…. CRH – corticosterone releasing hormone which causes

15. Pituitary gland to release ACTH – adrenocorticotrophic hormone which causes

16. Adrenal Gland to release stress hormones (cortisol or corticosteroid) - called glucocorticoids

17. negative feedback loop glucoccorticoids in the blood cause both hypothalamus and pituitary gland to stop releasing CRH and ACTH

18. Does stress have adverse effects on the CNS? Sapolsky –rats - daily injection of corticosterone decreased dendrites in hippocampal neurons –vervet monkeys - 1989 gastric ulcers, overactive adrenal gland, degeneration and depletion of cortical neurons

19. Chronic stress can reduce n of cells in hippocampus

20. What about chronic stress in humans and CNS? Cushings Syndrome - –increased glucocorticoid release (can be reversed with treatment) PTSD - Depressed patients

22. How might this happen? Increased cortisol or corticosterone –increase Ca+2 influx increased risk of overexcitation

23. What can increased cortisol do? - increase Ca+2 influx

24. What about stress and immune function?

25. A bit of background on the immune system Immune system - –identifies and eliminates foreign materials that contact or enter body, foreign materials can be bacteria, viruses, parasites, donated organs –also identifies and destroys cells that have undergone alterations (unusual rates of cell division for example) –immune system recognizes something on the surface of these called antigens and produces antibodies

26. How does the immune system do this? - manufactures specialized cells (leukocytes or white blood cells) that originate in bone marrow and travel to other cells to mature) b cells - mature in bone marrow –make antibodies that weaken or mark the antigen for destruction by other cells t cells - mature in thymus –cytotoxic t cells - can destroy target cells –helper t cells - help immune response natural killer cells - destroy certain kinds of tumors and infected cells

27. Can stress disrupt immune function? Yes- clinical data and animal studies Examples: –early Skylab astronauts - splashdown - –acute stress- decreased T cells –sleep deprivation study - kept awake 48 hrs - –reduced B cell and T cell response

28. Can stress disrupt immune function? Yes- clinical data and animal studies Examples: –early Skylab astronauts - splashdown - –sleep deprivation study - kept awake 48 hrs - –academic exams medical students

29. Do these changes following acute stressors impact health?

30. What about more chronic stressors? Chronic stress situations –examples: Is this associated with increased susceptibility to disease?

33. Chronic stress affects immune response in terms of illness incidence and recovery

34. Overall, 57.8% of respondents reported at least one PTSD symptom in a 30 day period (6 - 8 weeks after 9/11)

35. How might chronic stress mediate these effects on immune system?

36. Increased cortisol and glucocorticoids - reduce lymphocytes in blood increased opiate release - can reduce lymphocytes response increased catecholamine release -

37. Role of Optimism Segerstrom –law students during their first semester

38. Role of Optimism Segerstrom –law students during their first semester –optimism associated with increased n of helper T cells increased natural killer cell activity