Sleep Disordered Breathing Induced by Cervical Spinal Cord Injury and Effect of Adenosine A1 Receptors Modulation in Rats.

Abstract

Sleep-disordered breathing (SDB) is very common after spinal cord injury (SCI). The present study was designed to evaluate the therapeutic efficacy of adenosine A1 receptor blockade (8-cyclopentyl-1,3-dipropylxanthine, DPCPX) on SDB in the rodent model of SCI. We hypothesized that SCI induced via left hemisection of the 2nd cervical segment (C2Hx) results in SDB. We further hypothesized that blockade of adenosine A1 receptors following C2Hx would reduce the severity of SDB. In the first experiment, adult male rats underwent left C2Hx or sham (laminectomy) surgery. Unrestrained whole-body plethysmography (WBP) and implanted wireless electroencephalogram (EEG) were used for assessment of breathing during spontaneous sleep and for the scoring of respiratory events at the acute (~1 week), and chronic (~6 weeks) time points following C2Hx. During the second experiment, the effect of oral administration of adenosine A1 receptor antagonist (DPCPX, 3 times a day for 4 days) on SCI induced SDB was assessed. C2Hx animals exhibited a higher apnea-hypopnea index (AHI) when compared to the sham group, respectively (35.5±12.6 vs.19.1±2.1 events/hour; p<0.001). AHI was elevated 6 weeks following C2Hx (week 6 32.0±5.0 vs. week 1 42.6±11.8 events/hour, respectively; p=0.12). In contrast to placebo, oral administration of DPCPX significantly decreased AHI 4 days after the treatment (159.8±26.7 vs. 69.5±8.9%; p<0.05). Cervical SCI is associated with the development of SDB in spontaneously breathing rats. Adenosine A1 blockade can serve as a therapeutic target for SDB induced by SCI.