Regional changes of cyclic 3 ',5 '-guanosine monophosphate in the spinal cord of the rabbit following brief repeated ischemic insults

The regional distribution of cyclic 3',5'-guanosine monophosphate was studi ed in the lumbosacral segments of the spinal cord of the rabbit under physi ological conditions acid following brief repeated sublethal ischemic insult s. While the basal cGMP level in the gray matter was about 0.120 nmol cGMP/ mg wet. wt., the level of cGMP in non-compartmentalized white matter was ab out half of this value. The highest level of cGMP in the compartmentalized gray matter was found in the dorsal horns, about 0.180 nmol cGMP/mg wet. wt ., whereas the level of cGMP was greatly reduced in the ventral horns, reac hing one half of the previous value. Multiple sublethal ischemic insults, r epeated at I-h intervals, caused a statistically significant de crease of c GMP in all gray matter regions. While the post-ischemic and post-reperfusio n level of cGMP in the dorsal horns remained relatively high in comparison with the intermediate zone and ventral horns, the changes of cGMP level det ected in the white matter columns differed considerably and resulted in a s tatistically significant cGMP increase in the dorsal and ventral columns an d, vice versa, a statistically significant decrease of cGMP was found in th e lateral columns.