Relative sparing of nitric oxide synthase-containing neurons in the hippocampal formation in Alzheimer's disease.

Nitric oxide (NO) is an endogenous neuromodulator that may mediate neurotoxic effects of glutamate. NO-synthesizing neurons are, however, resistant to NO- and glutamate-induced neurotoxicity. We now show that NO synthase neurons are selectively spared in patients with Alzheimer's disease, even in a severely affected region of the brain such as the hippocampal formation.