Short-term changes of NADPH diaphorase-exhibiting neuronal pools in the spinal cord of rabbit after repeated sublethal ischemia

The aim of this study was the histochemical characterization of NADPH diaph orase-positive neuronal pools in the rabbit lumbosacral segments using a mo del of single, repeated and multiple sublethal spinal cord ischemia. Follow ing a single 8-min sublethal spinal cord ischemia and I-hour reperfusion, t he staining of NADPH diaphorase-exhibiting neurons in the dorsal horn? peri central region, dorsal gray commissure and sacral parasympathetic nucleus w as comparable with the control sections. In contrast to the foregoing suble thal ischemia, a regionally different somatic NADPH diaphorase (NADPHd) sta ining was found after multiple sublethal spinal cord ischemia. Whereas an a lmost complete loss of the staining of large NADPHd-exhibiting somata in th e pericentral region was detected, the staining of the NADPHd-exhibiting ne uronal pools in the deep dorsal horn and sacral parasympathetic nucleus was fully preserved. Concomitantly, a prominent reduction of small NADPH diaph orase-positive neurons was noted in the superficial dorsal horn layers of l ower lumbar and sacral segments.