Vascular compliance limits during sleep deprivation and recovery sleep

Abstract

Study Objectives: Our previous studies showed that evoked hemodynamic responses are smaller during wake compared to sleep; suggesting neural activity is associated with vascular expansion and decreased compliance. We explored whether prolonged activity during sleep deprivation may exacerbate vascular expansion and blunt hemodynamic responses. Design: Evoked auditory responses were generated with periodic 65dB speaker clicks over a 72-h period and measured with cortical electrodes Evoked hemodynamic responses were measured simultaneously with optical techniques using three light-emitting diodes, and a photodiode. Setting: Animals were housed in separate 30×30×80cm enclosures, tethered to a commutator system and maintained on a 12-h light/dark cycle Food and water were available ad libitum. Patients or Participants: Seven adult female Sprague-Dawley rats. Interventions: Following a 24-h baseline recording, sleep deprivation was initiated for 0 to 10 h by gentle handling, followed by a 24-h recovery sleep recording. Evoked electrical and hemodynamic responses were measured before, during, and after sleep deprivation. Measurements and Results: Following deprivation, evoked hemodynamic amplitudes were blunted. Steady-state oxyhemoglobin concentration increased during deprivation and remained high during the initial recovery period before returning to baseline levels after approximately 9-h. Conclusions: Sleep deprivation resulted in blood vessel expansion and decreased compliance while lower basal neural activity during recovery sleep may allow blood vessel compliance to recover. Chronic sleep restriction or sleep deprivation could push the vasculature to critical levels limiting blood delivery, and leading to metabolic defcits with the potential for neural trauma.