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Sleep fragmentation impairs ventilatory long‐term facilitation via adenosine A1 receptors
Author(s) -
McGuire Michelle,
Tartar Jaime L.,
Cao Ying,
McCarley Robert W.,
White David P.,
Strecker Robert E.,
Ling Liming
Publication year - 2008
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2008.158121
Subject(s) - hypoxic ventilatory response , adenosine , anesthesia , adenosine a1 receptor , endocrinology , medicine , antagonist , adenosine receptor , respiratory system , psychology , receptor , agonist
Sleep fragmentation (SF), a primary feature of obstructive sleep apnoea (OSA), impairs hippocampal long‐term potentiation and causes cognitive/attention deficits. However, its influence upon respiratory control has hardly been studied. This study examined the effect of SF on ventilatory long‐term facilitation (LTF, a persistent augmentation of respiratory activity after episodic hypoxia) and the hypoxic ventilatory response (HVR), and investigated the role of adenosine A1 receptors in these SF effects in conscious adult male Sprague–Dawley rats. SF, confirmed by sleep architecture recordings, was achieved by periodic, forced locomotion in a rotating drum (30 s rotation/90 s stop for 24 h). LTF, elicited by five episodes of 5 min poikilocapnic hypoxia (10% O 2 ) with 5 min intervals, was measured by plethysmography. Resting ventilation and metabolic rate were unchanged, HVR was reduced (150.6 ± 3.5% versus 110.4 ± 12.3%) and LTF was eliminated (22.6 ± 0.5% versus −0.1 ± 1.3%) shortly after 24 h SF. The SF‐induced impairments were SF duration dependent, and completely reversible as HVR (< 24 h) and LTF (< 48 h) returned spontaneously to their pre‐SF values. The SF‐impaired HVR was improved (130.3 ± 4.2%) and SF‐eliminated LTF was restored (19.6 ± 0.9%) by systemic injection of the adenosine A1 receptor antagonist 8‐CPT (2.5 mg kg −1 ) ∼30 min before LTF elicitation. Both HVR and LTF were also similarly impaired by 24 h total sleep deprivation or 24 h repeated cage tapping‐induced SF, but not by a 24 h locomotion control protocol for SF. Collectively, these data suggest that: (1) 24 h SF impairs LTF and poikilocapnic HVR; (2) these impairments require A1 receptors; and (3) SF of OSA may exacerbate OSA via impaired ventilatory control mechanisms.