| Publication Abstract Display | | Type: Published Abstract | | Title: Beta2 adrenergic receptors are desensitized and downregulated in vulnerable caregivers of spouses with Alzheimer's disease. | | Authors: Adler KA, Mills PJ, Dimsdale JE, Ziegler MG, Patterson TL, Grant I | | Year: 2003 | | Publication: Psychosomatic Medicine | | Volume: 65 Issue: 1 Pages: A33 | | Abstract:Conditions involving sympathetic nervous system (SNS) activation are often associated with increased circulating catecholamines, desensitized and/or downregulated beta2 receptors, and elevated blood pressure (BP). Providing care for a spouse with Alzheimer’s disease (AD) is a potent chronic stressor that has been associated with SNS activation. We examined lymphocyte beta2 adrenergic receptor function, BP, and heart rate (HR) in caregivers of spouses with AD (N=53) and age-matched controls (N=26). Participants were elderly community-dwelling men (N=24) and women (N=55). Participants’ mean age was 71 +/- 9 years. Caregivers (CG) were broken down into two subgroups based on whether they had adequate respite time from their duties (non-vulnerable, N=41) or not (vulnerable, N=12). Lymphocytes were isolated from peripheral blood via density centrifugation. Receptor density was determined by radioligand binding. Receptor sensitivity was calculated as the ratio of agonist-stimulated to basal cellular cAMP, as measured by radioimmunoassay. BP and HR measurements were made by DynaMap and expressed as the mean of 3 resting values, taken 5 minutes apart. Vulnerable CG had less sensitive lymphocyte beta2 receptors than did age matched controls (3.3 +/- 1.4 vs. 5.7 +/- 3.0, p=.02). Also, vulnerable CG tended to have lower beta2 receptor density than non-vulnerable CG (294 +/-55 vs. 448 +/- 210 sites/cell, p=.09). All groups had equivalent resting BP and heart rate (HR). Across all participants, greater beta2 sensitivity was associated with higher HR (r=.24, p=.05). Greater beta2 density was associated with higher SBP (r=.32, p=.02). It appears that vulnerable caregivers exhibit stress-related alterations in beta2 sensitivity and density. However, these changes have not yet exerted an effect on cardiovascular functioning, as measured by HR and BP. |
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