[Effect of epidural morphine analgesia on the NO-forming activity of nociceptive neurons of the spinal ganglia and bone marrow].

The effect of epidural morphine analgesia on NO mechanisms was studied during the primary and secondary sensitizations. The nitro-oxide synthase (NOS) activity was evaluated by the method of Home and Vincent, 1989, (identification of NADPH diaphorase). NOS and NADPH diaphorases are two double enzymes in cells with a synchronously changing activity. The NOS activity is in line with the level of the NO secretion. The enzyme was measured on a microdensitometer. The findings evidence an active involvement of NO mechanisms in the formation of primary and secondary hyperalgesia, and the injection of morphine caused a significant decrease in the count of NO-expressing neurons in the total number of cells with high and average activities of the enzyme.