Expression of cGMP-dependent protein kinases (I and II) and neuronal nitric oxide synthase in the developing rat cerebellum

The expression of neuronal nitric oxide synthase (nNOS) and the cGMP-dependent protein kinases cGKI and cGKII in rat cerebellum was evaluated at different developmental stages by quantitative RT-PCR and Western blotting. mRNAs coding for these proteins were detected in the cerebella of rats aged 7, 14 and 21 days. Expression levels, nevertheless, varied significantly at each of these developmental stages. While nNOS and cGKI mRNA levels steadily increased during development, cGKII mRNA showed a different behaviour pattern, with similar levels observed on postnatal days 7 and 14 and increased levels noted on postnatal day 21. Moreover, protein expression profiles for nNOS and cGKI showed similar patterns to the mRNAs encoding these proteins. Our results reveal the developmental regulation of the expression of these proteins in the cerebellum, giving rise to higher levels as the cerebellum matures.