Physical chitosan microhydrogels as scaffolds for spinal cord injury restoration and axon regeneration.

Recovery from traumatic spinal cord injury (SCI) usually fails due to a cascade of cellular and molecular events that compromise neural tissue reconstitution by giving rise to glial scarring and cavity formation. We designed a scaffold material for SCI treatment containing only chitosan and water as fragmented physical hydrogel suspension (Chitosan-FPHS), with defined degree of acetylation (DA), polymer concentration, and mean fragment size. Implantation of Chitosan-FPHS alone into rat spinal cord immediately after a bilateral dorsal hemisection promoted reconstitution of spinal tissue and vasculature, and diminished fibrous glial scarring: with astrocyte processes primarily oriented towards the lesion, the border between lesion site and intact tissue became permissive for regrowth of numerous axons into, and for some even beyond the lesion site.

Neurons expressing individual enzymes of dopamine synthesis in the mediobasal hypothalamus of adult rats: functional significance and topographic interrelations.

Besides dopaminergic (DA-ergic) neurons having all enzymes of DA synthesis, tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC), "monoenzymatic" neurons expressing only one of them were found in the brain, mostly in the mediobasal hypothalamus (MBH). The aim of this study was to test our hypothesis that DA is synthesized by monoenzymatic neurons, i.e.

Giant scaffolding protein AHNAK1 interacts with β-dystroglycan and controls motility and mechanical properties of Schwann cells.

The profound morphofunctional changes that Schwann cells (SCs) undergo during their migration and elongation on axons, as well as during axon sorting, ensheathment, and myelination, require their close interaction with the surrounding laminin-rich basal lamina. In contrast to myelinating central nervous system glia, SCs strongly and constitutively express the giant scaffolding protein AHNAK1, localized essentially underneath the outer, abaxonal plasma membrane. Using electron microscopy, we show here that in the sciatic nerve of ahnak1(-) (/) (-) mice the ultrastructure of myelinated, and unmyelinated (Remak) fibers is affected.

Comparative distribution of the mRNAs encoding urotensin I and urotensin II in zebrafish.

The neural neurosecretory system of fishes produces two biologically active neuropeptides, i.e. the corticotropin-releasing hormone paralog urotensin I (UI) and the somatostatin-related peptide urotensin II (UII).

Caudal neurosecretory system of the zebrafish: ultrastructural organization and immunocytochemical detection of urotensins.

The caudal neurosecretory system is described here for the first time in the zebrafish, one of the most important models used to study biological processes. Light- and electron-microscopical approaches have been employed to describe the structural organization of Dahlgren cells and the urophysis, together with the immunohistochemical localization of urotensin I and II (UI and UII) peptides. Two latero-ventral bands of neuronal perikarya in the caudal spinal cord project axons to the urophysis.