PYRAMIDAL NEURONS IN PATHOLOGICAL HUMAN MOTOR CORTEX EXPRESS NITRIC-OXIDE SYNTHASE

The enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NAD PH diaphorase) is widely used as a sensitive marker for indicating the presence of nitric oxide synthase in neurones. Pyramidal neurones in the healthy neocortex do not contain detectable levels of nitric oxide synthase. However, in the precentral gyrus of brains showing patholog ical damage, a high proportion of Betz cells (11-50%) and some smaller pyramidal neurones contained low to moderate levels of NADPH diaphora se. They were located in layers V and VI and were present in a newborn baby, older children and elderly adults. Thus, under pathological con ditions, some pyramidal neurones are apparently capable of synthesisin g nitric oxide and this may have a neuroprotective function.