Beta 2-adrenergic receptor characteristics in sleep apnea patients.
This study examined the relationship between sleep apnea and beta 2-adrenergic receptor characteristics. Using standard polysomnography, individuals were classified as either apneic (n = 15) or mild to nonapneic (n = 15) according to their respiratory disturbance index (RDI). Subjects were similar in terms of sodium excretion and blood pressure. Apneic subjects showed a decrease in beta 2-adrenergic receptor sensitivity (p = 0.01) [as determined by isoproterenol-stimulated cyclic adenosine 5'-monophosphate (AMP) production in lymphocytes] and an increased binding affinity to the beta receptor antagonist [125I]iodopindolol (p < 0.001). beta receptor density was also diminished in apneics, but not significantly (p = 0.08). Forskolin-stimulated cyclic AMP was not significantly different between the groups, indicating a similarity in postreceptor Gs-adenylate cyclase activation. Across all subjects, RDI was negatively correlated with beta receptor sensitivity (r = -0.35, p = 0.05) and Kd (r = -0.54, p < 0.01) and positively correlated with systolic blood pressure (r = 0.37, p < 0.05). The findings indicate that sleep apnea is associated with a diminished beta 2-adrenergic receptor function but no change in postreceptor components and suggest a mechanism for the high comorbidity between sleep apnea and hypertension.
Mills
P J
PJ
Department of Psychiatry, University of California, San Diego, La Jolla 92103-0804, USA.
Dimsdale
J E
JE
Coy
T V
TV
Ancoli-Israel
S
S
Clausen
J L
JL
Nelesen
R A
RA
D000249:Adenosine Monophosphate / Q000097:blood / Q000378:metabolism; D000319:Adrenergic beta-Antagonists; D000328:Adult; D006801:Humans; D006973:Hypertension / Q000150:complications; D007545:Isoproterenol / Q000494:pharmacology; D008875:Middle Aged; D017286:Polysomnography; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000175:diagnosis*
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D000249:Adenosine Monophosphate; D011433:Propranolol; D007545:Isoproterenol