[Calmodulin and neuron: immunohistochemical studies].

Calmodulin is present in higher concentrations in brain tissues. The content rapidly increased during the 2nd postnatal week in rat brain. Although the protein is ubiquitous in all eukaryotic cells, immunohistochemical studies have revealed that calmodulin is mainly localized in the neurons, exhibiting a similar distribution to that of gamma-type neuron-specific enolase. In the mouse retina, both calmodulin and gamma-enolase were found to be localized in optic nerves, ganglion cells, and inner and outer plexiform layers. The development study showed that gamma-enolase increased in the 2nd postnatal week and that the levels of calmodulin did not significantly change in that stage. In the mouse retina with an inherited retinal dysplasia (C3H), in which all the photoreceptor cells degenerate during the 2nd and 3rd postnatal weeks, calmodulin-specific staining decreased in the residual layers. Calmodulin is also enriched in mammalian testes. In the mouse testis, levels of calmodulin were high in the spermatocytes and in the spermatids, as compared to the level in spermatozoa. This suggests that the large amount of calmodulin in the testis may be associated with miotic divisions and/or spermatogenesis. Immunocytochemical staining of calmodulin in C6 glioma cells and PC12 pheochromocytoma cells showed a high level of calmodulin to be localized on the half spindles between poles and chromosomes in mitotic cells. The protein was also shown to be localized on fibrous structures in the interphase of those cells.(ABSTRACT TRUNCATED AT 250 WORDS)