Michael G. Ziegler

Effects of chronic stress on beta-adrenergic receptors in the homeless

&NA; This study examined the role of chronic life stress (homelessness), coping style, and hypertension on beta‐adrenergic receptors in a sample of homeless men. Sixteen healthy normotensive subjects and nine untreated hypertensive subjects were studied. Life stress was measured with the Brown and Harris categorization; coping style was measured with the Ways of Coping Scale. Lymphocyte beta‐adrenergic receptors were characterized in terms of receptor density (Bmax). Individuals with high life stress had lower Bmax (p < .005). In multiple regression analyses, 50% of the variance in Bmax was accounted for by life stress and coping style (p = .01). Receptor measures may be useful for characterizing the physiological response to continuing life adversity.

Beta-adrenergic receptors predict heart rate reactivity to a psychosocial stressor.

&NA; We examined the ability of baseline measures of receptors (lymphocyte beta‐adrenergic) and nonreceptors (plasma catecholamines, heart rate, and blood pressure) to predict cardiovascular responses to a mental arithmetic task. Twenty‐five male volunteers served as subjects. Nonreceptor measures predicted the heart rate response to stress poorly (p = 0.67). However, beta receptor density and sensitivity explained 48.4% of the variance in heart rate response (p = 0.007). When both receptor and nonreceptor measures were used together, they predicted 76.6% of the variance (p = 0.005), which was more than was explained by either receptor or nonreceptor baseline measurements alone (p = 0.001). Receptor measures may thus greatly improve the prediction of reactivity.

Patterns of adrenergic receptors and adrenergic agonists underlying cardiovascular responses to a psychological challenge.

&NA; Numerous physiological and biochemical factors contribute to the dynamic regulation of the cardiovascular system. This study used a cluster analytic statistical technique to discern patterns of adrenergic receptors and adrenergic agonists underlying cardiovascular responses to a laboratory challenge. Fifty hypertensive and normotensive black and white individuals had their beta‐ and alpha‐adrenergic receptor sensitivity determined through agonist infusions. Norepinephrine, epinephrine, blood pressure, and heart rate responses to a standardized mental arithmetic task were also obtained. The cluster analysis identified four subgroups of individuals having distinct patterns of receptor and neurohormonal regulation of end‐organ responses. In general, the data indicated that end‐organ cardiovascular responses are, in part determined by the sensitivity of adrenergic receptors and the accompanying catecholamine responses. The findings also suggest that for some individuals nonadrenergic factors play a more dominant role than adrenergic mechanisms in determining cardiovascular pressor responses.

Does chromogranin A respond to short-term mild physiologic challenge?

Plasma chromogranin A, norepinephrine, epinephrine, blood pressure, and heart rate were examined in 51 unmedicated volunteers at rest, in response to postural stimulation, and in response to a mild behavioral stressor. The short-term stressors led to the expected increases in catecholamines, blood pressure, and heart rate; however, chromogranin A was not influenced by these stimuli. Chromogranin A levels were not higher in the hypertensives, nor were they correlated with any of the other physiological variables. Although chromogranin A is coreleased with catecholamines from the sympathoadrenomedullary system, it does not respond to modest short-term postural or psychological stimuli that simultaneously evoke changes in other variables relevant to the sympathetic nervous system.

Neuroimmune Activation in Sleep Apnea

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder, characterized by repeated disruptions of breathing during sleep. The sleep fragmentation and the accompanying hypoxemia lead to many negative consequences including cardiovascular diseases, cognitive impairment, daytime sleepiness, fatigue, and depressive symptoms (Parish and Somers 2004; Reimer and Flemons 2003). Originally viewed as an interesting but rare malady, OSA is now recognized as a common disorder that is associated with major morbidity and mortality (Newman et al. 2001). Noradrenergic activation, as indicated by augmented sympathetic neural activity, elevated circulating norepinephrine (NE) levels, and elevated urinary NE excretion, is a hallmark of OSA (Carlson, Hedner, Elam, Ejnell, Sellgren, and Wallin 1993; Dimsdale, Coy, Ziegler, Ancoli-Israel, and Clausen 1995; Fletcher 2003; Eisensehr et al. 1998). There are numerous physiologically relevant consequences of this noradrenergic activation, including adrenergic receptor desensitization (Grote, Hraiczi, and Hedner 2000; Mills, Dimsdale, Coy, Ancoli-Israel, Clausen, and Nelesen 1995; Mills, Dimsdale, Ancoli-Israel, Clausen, and Loredo 1998; Nelesen, Dimsdale, Mills, Clausen, and Ancoli-Israel 1996), high blood pressure (Norman et al. 2006; Robinson, Stradling, and Davies 2004), and elevations in proinflammatory cytokine levels (Vgontzas et al. 2000; Yokoe et al. 2003). This chapter will review studies that our group and others have conducted documenting neuroimmune effects of OSA, as well as studies documenting the effects of successful treatment of OSA on these physiological systems.

58 Increased cellular adhesion molecule expression on lymphocytes and monocytes following acute stress in elderly spousal Alzheimer disease caregivers

particular, attending to the spiritual dimension, which has been largely ignored in psychosocial interventions, contributes to positive outcomes. Also, for cancer patients, failure to receive psychosocial intervention may result in reduced social support in this study. This is the first study that provides psychoneuroendocrine evidence on the efficacy of psychosocial interventions for breast cancer patients in Hong Kong. The methodology developed in the present study can be generalized to systematically evaluate the psychoneuroendocrine effects of different psychosocial interventions for different clinical populations. Results from next phase with larger samples and longer follow-up periods may provide deeper understanding on the holistic intervention approach and the relative effectiveness of various therapeutic components.