STUDY OBJECTIVE: To characterize the role of alpha-receptors in autonomic control of digital skin blood flow change in response to obstructive apnea-hypopnea events. DESIGN: Experimental intervention study. SETTING: Sleep laboratory in a university hospital. PATIENTS: Eight male patients with severe obstructive sleep apnea (OSA). INTERVENTIONS: Patients received four cumulative dosage steps of phentolamine (0.066, 0.2, 2 and 5 [n=3] microg/min/100 ml forearm tissue) via brachial artery infusion during nonrapid eye movement sleep (stage 1 and 2). MEASUREMENTS AND RESULTS: The pulse amplitude determined with peripheral arterial tonometry (PAT) was periodically attenuated during the immediate post apnea-hypopnea period coinciding with arousal. PAT ratio (smallest pulse amplitude post apnea divided by largest pulse amplitude during apnea), was determined as a measure of digital vasoconstriction. We found that, compared with baseline, PAT ratio dose-dependently increased during phentolamine (0.2, 2 and 5 microg) infusion by 11.2+/-1.7%, 24.4+/-2.1% and 30.9+/-4.1%, respectively (P<0.001). Systemic blood pressure and heart rate were largely unaffected by the pharmacological intervention. CONCLUSION: OSA related alteration of the pulse amplitude includes a constriction of digital skin vasculature that to a large extent is mediated via sympathoadrenergic alpha-receptors.
STUDY OBJECTIVE: To characterize the role of alpha-receptors in autonomic control of digital skin blood flow change in response to obstructive apnea-hypopnea events. DESIGN: Experimental intervention study. SETTING: Sleep laboratory in a university hospital. PATIENTS: Eight male patients with severe obstructive sleep apnea (OSA). INTERVENTIONS:Patients received four cumulative dosage steps of phentolamine (0.066, 0.2, 2 and 5 [n=3] microg/min/100 ml forearm tissue) via brachial artery infusion during nonrapid eye movement sleep (stage 1 and 2). MEASUREMENTS AND RESULTS: The pulse amplitude determined with peripheral arterial tonometry (PAT) was periodically attenuated during the immediate post apnea-hypopnea period coinciding with arousal. PAT ratio (smallest pulse amplitude post apnea divided by largest pulse amplitude during apnea), was determined as a measure of digital vasoconstriction. We found that, compared with baseline, PAT ratio dose-dependently increased during phentolamine (0.2, 2 and 5 microg) infusion by 11.2+/-1.7%, 24.4+/-2.1% and 30.9+/-4.1%, respectively (P<0.001). Systemic blood pressure and heart rate were largely unaffected by the pharmacological intervention. CONCLUSION: OSA related alteration of the pulse amplitude includes a constriction of digital skin vasculature that to a large extent is mediated via sympathoadrenergic alpha-receptors.
Authors: Brian M O'Reilly; Qing Wang; Jacob Collen; Panagiotis Matsangas; Christopher J Colombo; Vincent Mysliwiec Journal: J Clin Sleep Med Date: 2022-06-01 Impact factor: 4.324
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