Experimental investigations on the regulation of the blood circulation of the spinal cord. II. The influence of vaso-active substances on the haemodynamics of the spinal cord under physiological conditions

Effect of vasodilators and myelotomy on recovery after acute spinal cord injury in rats

The effect of papaverine, nitroprusside, or myelotomy on the recovery of spinal cord function was studied in rats after acute cord-compression injury. Spinal cord recovery was measured by a quantitative method of clinical assessment previously developed in our laboratory. Neither papaverine nor nitroprusside improved recovery of cord function. Dorsal midline myelotomy extending anteriorly as far as the central canal did not produce significant improvement (p greater than 0.05). However, when the myelotomy extended completely through the cord in the anteroposterior plane significant improvement (p less than 0.01) was obtained.

Hyperemia, CO2 responsiveness, and autoregulation in the white matter following experimental spinal cord injury

The authors present the results of a controlled, randomized study of alterations in spinal cord blood flow, CO2 responsiveness, and autoregulation following experimental spinal cord injury in cats. Permanent paraplegia is shown to be associated with persistent hyperemia, loss of CO2 responsiveness, and impaired autoregulation in the white matter at the injury site. Probable mechanisms underlying these changes in spinal cord vasomotor control are discussed. Marked similarities between vascular responses of injured spinal cord and luxury perfusion of the brain are pointed out.

Review of the measurement of normal spinal cord blood flow

The field of spinal cord blood flow (SCBF) is reviewed. The methodology currently being used to evaluate SCBF is critically analyzed. The review demonstrates that there is a paucity of reliable quantitative measurements of SCBF. The effects of arterial pCO2, pO2 and blood pressure variations as well as the effects of several pharmacological agents on SCBF are also discussed.

Change of local spinal cord blood flow in acute ischaemia

The local blood flow of the spinal cord was recorded by the hydrogen polarographic method with platinum electrodes. The blood flow and its changes were measured during acute ischaemia caused by compression of the thoracic aorta, and also after release of compression. Ten cats were included in these experiments, and more than 100 measurements were made in the lumbar region of the spinal cord. In the grey matter a high flow was observed in every case, resembling that in the cerebral cortex. Reduction of the lumen of the thoracic aorta by one half resulted in a 23%, and by three quarters in a 60-70% decrease in blood flow. With total occlusion there was practically entire cessation of flow. Rapid restitution of blood supply in the grey matter of the spinal cord caused a 65%, and in the white matter a 170% increase in blood flow due to reactive hyperaemia. Normal flow rates returned within 2-2.5 minutes.

The pathophysiological response to spinal cord injury

✓ In this review of spinal cord injury research, the author has selected contributions which in his opinion best represent modern experimental concepts regarding the mechanism and management of spinal cord injuries. He has placed special emphasis on the controversial issues appropriate to a new, stimulating, and competitive area of research.

Blood flow in the central and peripheral nervous system of dogs using a particle distribution method

In this study known activities of 85 Sr and 169 Yb-labeled microspheres were injected sequentially into the left ventricle of anesthetized dogs. Cardiac output was determined before and after each microsphere injection. Blood flow to brain, brain stem, spinal cord, and sciatic nerve was measured from fractional distribution of the microspheres in the tissue samples. Both blood flow and fractional uptake value tended to be higher for brain and brain stem than for spinal cord or sciatic nerve. Increases in arterial Pa CO CO2 were positively correlated with increases in blood flow to both central and peripheral nervous tissue. Initial trapping of the labeled microspheres seems to have little effect on subsequent flow to the tissue capillary bed. It appears that the particle distribution technique may provide a reasonable estimate of blood flow in central and peripheral nervous tissue of dogs.