title: Intranuclear inclusions in the developing neurons of the rat cuneate nuclei.
abstract: The ultrastructure of intranuclear rodlets, microtubules, fibrillar lattices and membranous inclusions found in the developing cuneate nuclei of rats is described. Rodlets, ranging in diameter from 96--312 nm and in length from 1--2 micrometer, are made up of tightly packed straight filaments measuring 5--8 nm in diameter. Microtubules with a diameter of 26 nm are clustered together. Fibrillar lattices are made up of fibrils with a diameter of 9 nm arranged in layers or sets. Two to nine sets make up a lattice, with a maximum width of 68 nm, in which the adjacent sets are arranged at an angle to each other. Rodlets and fibrillar lattices occur in 6.8% of the neurons. Membranous inclusions, reported here for the first time in normal neurons, are of 2 types: small vesicles of 0.1--0.6 micrometer and large vacuoles measuring 1--2 micrometer. Both types are bounded by either a single or a double membrane and generally have an electron lucent content. Membranous inclusions occur in 25.3% of the neurons. Changes in the frequency of occurrence of the various intranuclear inclusions in the course of postnatal development are also reported.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D002479:Inclusion Bodies / Q000648:ultrastructure*; D008526:Medulla Oblongata / Q000254:growth & development / Q000648:ultrastructure*; D008870:Microtubules / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure*; D051381:Rats