adenosine-3--5--cyclic-phosphorothioate and Apnea

The present study investigated the involvement of the adenosine 3'5'-cyclic monophosphate-dependent protein kinase A (cAMP-PKA) pathway in the activation of the crossed-phrenic pathways after left C2 spinal cord hemisection. Experiments were conducted on left C2 spinal cord hemisected, anesthetized, vagotomized, pancuronium paralyzed, and artificially ventilated male Sprague-Dawley rats. One week post-injury, the ipsilateral phrenic nerve exhibited no respiratory-related activity indicating a functionally complete hemisection. Intrathecal spinal cord administration of the cAMP analog, 8-Br-cAMP at the level of the phrenic nucleus resulted in an enhancement of contralateral phrenic nerve output and a restoration of respiratory-related activity in the phrenic nerve ipsilateral to the hemisection. Furthermore, pre-treatment with Rp-8-Br-cAMP, a PKA inhibitor, abolished the effects of 8-Br-cAMP. These results suggest that PKA activation is necessary for the cAMP-mediated respiratory recovery following high cervical spinal cord injury and that activation of intracellular signaling cascades may represent an important strategy for improving respiratory function after spinal cord injury.

Topics: Animals; Apnea; Carbon Dioxide; Cervical Vertebrae; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data Interpretation, Statistical; Electrophysiology; Enzyme Inhibitors; Functional Laterality; Male; Phrenic Nerve; Rats; Rats, Sprague-Dawley; Respiratory Physiological Phenomena; Signal Transduction; Spinal Cord; Spinal Cord Injuries; Thionucleotides