Expression of Fos (brown) and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d, dark blue) in the lateral wing area of the dorsal raphe nucleus (DRN) of a capsaicin-treated (“stressed”) rat. Fos is an indicator of intracellular excitation and NADPH-d is a marker for neuronal nitric oxide synthase (NOS), an unorthodox neuromodulatory molecule in the brain. This illustration suggests that under “stressful conditions” nitric oxide circuits and at least one other neurotransmitter system are activated in the rodent DRN.
Chuma Okere, Ph.D., Waterhouse Laboratory