Abstract P32: Neurogenic Activation Mediates Remote Non-Ischemic Cardioprotection
Table of Contents Our previous studies have identified a powerful cardioprotective phenomenon that occurs subsequent to an abdominal skin incision, named RPCT and initiated by a neurogenic ganglionic mechanism. These results led us to hypothesize that sensory nerve stimulation was the initiator of this remote cardioprotection. Herein, we demonstrate that a similar cardioprotective effect is reproduced by an abdominal nociceptive stimulation (ANS), either by electrical or by chemical stimulation of remote peripheral sensory nerves. We name this phenomenon ANS-PC.
Methods, an in vivo mouse I/R model was used. ANS was performed 15 minutes prior to I/R or at the beginning of reperfusion with the needles placed along a transverse line on the anterior abdomen. ANS treatment was performed 15 min prior to ischemia, or at reperfusion. Infarct size was evaluated after a 45 min coronary occlusion (24h reperfusion). We employed pharmacologic, immunohistochemical analysis and microsurgical manipulation to determine the involvement of neurogenic transmission in ANS-PC. We first tested whether spinal cord transection (vertebral C7 and T7 levels) or peripheral C-fiber nerve blockade (local anesthetic) prevent development of ANS-PC.
The results of our studies demonstrate that the cardioprotective effect of ANS-PC is prevented by peripheral nerve blockade. Spinal cord transection at the C7 level had no effect on ANS-PC whereas transection at the T7 level completely abolished the effect of ANS-PC.
In conclusion, our results support
activation of C-fiber nonciceptors from the abdominal skin initiate ANS-PC and
the signal generated at the remote site is relayed to the heart by the spinal cord.
Understanding the novel mechanism of remote preconditioning and postconditioning after ANS will allow the development of new surgical, electrical or pharmacologic strategies to protect the heart from I/R injury.