THE EFFECT ON MUSCLE GLYCOGEN OF SHOCK DUE TO SPINAL CORD DESTRUCTION, AND OF HAEMORRHAGIC SHOCK WITH PERIPHERAL DENERVATION

In rats with shock due to spinal cord destruction (pithed rats) and severe terminal hypoglycaemia muscle glycogen remains normal, whereas it falls in shock due to other causes. To explain this difference the role of denervation on muscle glycogen was investigated. In rats with destruction of the lower part of the spinal cord, the denervated hindlimbs showed a higher muscle glycogen concentration than the normally innervated forelimbs, in spite of severe shock. In other experiments is was found that in haemorrhagic shock one‐sided proximal interruption of the femoral nerve resulted in a higher glycogen concentration in the rectus femoris than on the other sham‐operated side. However, the same differences were found also in the gastrocnemius, whose motor nerve fibres were intact. Blockade with phenoxybenzamine prior to haemorrhagic shock abolished this difference between the denervated and intact limb completely. It is concluded that a section of the femoral nerve interrupts accompanying sympathetic adrenergic fibres to the hindlimb, thereby preventing vasoconstriction and reducing tissue hypoxia during haemorrhagic shock. The normal muscle glycogen concentration during severe spinal shock must be explained by a failure of reflexogenic hyperactivity of the sympathetic nervous vasomotor system. In studies on the effects of peripheral denervation, the possible role of interruption of accompanying autonomic nervous fibres is often neglected.