Nitric oxide synthase expression in single hippocampal neurons.

The presence of nitric oxide synthase (NOS) in CA1 pyramidal cells of the rat hippocampus was demonstrated by single-cell PCR. NOS-specific primers were used to amplify mRNA isolated from single hippocampal neurons. The sequence of the major amplification-product obtained was identical to that of the constitutively expressed brain-isoform of NOS. These results confirm immunocytochemical data that NOS is present in CA1, and, therefore, nitric oxide could function as a retrograde messenger in long-term potentiation.