/3-Endorphin in Experimental Canine Spinal Ischemia

Plasma and cerebrospinal fluid 0-endorphin concentrations were radioimmunologically assayed in dogs subjected to spinal cord ischemia induced by infrarenal aortic ligature and in control sham-operated dogs. Plasma /3-endorphin levels rose significantly following surgery in control dogs but were unaffected by spinal ischemia. On the other hand, a significant increase in cerebrospinal fluid /3-endorphin concentration occurred after spinal ischemia, while surgical stress had no significant effect. Thus, the origins of plasma and cerebrospinal fluid /3-endorphin may be different, with the former secreted from the hypophysis and the latter from nervous tissue. Observed changes in cerebrospinal fluid /3-endorphin concentration could be related to the ischemic lesion of nervous tissue while the changes in plasma levels may reflect general stressing factors such as the surgery in our experiments. (Stroke 1989;20:253-258)