S. Yoshida

Localization of basic fibroblast growth factor-like immunoreactivity in the rat brain.

The immunohistochemical localization of basic fibroblast growth factor (bFGF) was studied in the adult rat brain, using a specific antibody against a synthetic bFGF fragment (the N-terminal 12 residues). Widespread but uneven regional localization of bFGF-like immunoreactive neurons and fibers was observed. Ependymal cells were also stained. The immunoreactive neurons were found in the cerebral cortex, olfactory bulb, septum, basal magnocellular nuclei, thalamus, hypothalamus, globus pallidus, hippocampus, amygdala, red nucleus, central gray of the midbrain, cerebellum, dorsal tegmental area, reticular formation, cranial motor nuclei and spinal cord. Immunoreactive fiber bundles and nerve terminals were also detected. These results indicate that bFGF is produced by or present in a specific neuronal cell population of the central nervous system.

Effects of nerve crush and transection on mRNA levels for nerve growth factor receptor in the rat facial motoneurons.

We found that the level of nerve growth factor receptor (NGF-R) mRNA in facial motoneurons was increased after both facial nerve crushing and transection by means of in situ hybridization histochemistry. The increased level of NGF-R mRNA was maintained for at least 8 weeks after facial nerve transection, while facial nerve crushing caused only a transient increase. Thus, expression of NGF-R mRNA paralleled the axonal regeneration process. In addition, the increase of NGF-R mRNA with crushing was more pronounced than with transection from the 3rd to the 14th day after the insult.

Fine structure of noradrenergic terminals and their synapses in the rat spinal dorsal horn: an immunohistochemical study

Noradrenergic fibers in the spinal dorsal horn originate from neurons in the A5-7 cell groups, and may participate in the modulation of pain. Here we studied the fine structure of noradrenergic terminals in the rat by immunohistochemistry using antiserum against dopamine-beta-hydroxylase (DBH). We also investigated the relationship between such terminals and primary afferent terminals. DBH-like immunoreactive terminals were found in lamina I and the outer layer of lamina II of the dorsal horn and they contained many clear round vesicles and some large granular vesicles. More than half of these terminals made synaptic contact with other neuronal elements with membrane specialization. Most of the postsynaptic structures of these terminals were small dendrites (69%); 28% were spines, and no synaptic contact was made with primary afferent terminals. These findings suggest that noradrenaline acts on the spinal dorsal horn neurons postsynaptically mainly via a direct synaptic mechanism.

Calcium-binding proteins calbindin and parvalbumin in the superficial dorsal horn of the rat spinal cord

Neurons containing the calcium-binding proteins, calbindin or parvalbumin, were studied by immunohistochemistry in the superficial dorsal horn of the rat spinal cord. Calbindin-containing cells were found in laminae I, II and III, being more abundant in laminae I and II. Some of the neurons in lamina I containing calbindin projected to the supraspinal area. Parvalbumin-containing neurons were mainly distributed in laminae IIi and III. Calbindin and parvalbumin were not detected in the same cells. Some 75% of the neurotensin-like immunoreactive neurons contained calbindin, which corresponded to 13% of the calbindin-containing neurons. Calbindin was sometimes found in the same cells with substance P, enkephalin or somatostatin but less frequently (44-46% of the peptide-containing neurons). Parvalbumin was not found together with these peptides. Electron microscopy showed that the immunoreactive products of calbindin or parvalbumin were mostly in the dendrites or cell bodies. Immunoreactive axon terminals were relatively few. In rhizotomized animals, neurons containing one of these proteins in laminae II and III were found to receive direct inputs of primary afferent fibers. These findings indicate that neurons containing these two proteins belong to different subpopulations of dorsal horn neurons. They may be important in primary afferent processing.

Localization of basic FGF-like immunoreactivity in the hypothalamo-hypophyseal neuroendocrine axis

We examined the localization of basic fibroblast growth factor (basic FGF) in the adult rat brain by immunohistochemical and Western blotting analysis using a specific antibody against a synthetic basic FGF fragment (N-terminal 12 residues). The antibody did not cross-react with acidic FGF. Basic FGF-like immunoreactivity was located exclusively in the neuronal elements and had very heterogeneous distribution. Immunoreactive cell bodies were observed in the paraventricular, supraoptic and circular nuclei of the hypothalamus. Numerous immunoreactive neuronal processes originating from these basic FGF-positive cells extended lateroventrally and then caudally to the internal layer of the median eminence. In addition, the neurohypophysis contained a significant number of basic FGF-like immunoreactive fibers. Western-blotting analysis revealed that the hypothalamus and the hypophysis contained a main band of basic FGF immunoreactive with an apparent molecular weight of 17 kDa. These results show that the hypothalamo-hypophyseal neuroendocrine pathway contains basic FGF.

Coexistence of amyloid β-protein precursor and basic fibroblast growth factor in single cells of the rat parietal cortex, hippocampus and basal magnocellular nucleus

The coexistence of amyloid beta-protein precursor (APP) and basic fibroblast growth factor (basic FGF) in single cells of the parietal cortex, hippocampus and basal magnocellular nucleus was investigated immunohistochemically in adult rats. A monoclonal antibody directed against human recombinant APP and a polyclonal antibody against a synthetic fragment of basic FGF (the N-terminal 12 residues) were used. APP and basic FGF were frequently colocalized in the pyramidal cells of layers III and V of the parietal cortex, in the pyramidal and extrapyramidal cells of the hippocampus, and in large cells of the medial septal nucleus and the horizontal limb of the diagonal band of Broca. Such a frequent colocalization suggests a close functional relationship between APP and basic FGF in the neuronal cells.

Ontogeny of visinin-like immunoreactive structures in the rat cerebellum and vestibular nuclei: An immunohistochemical analysis

The ontogeny of visinin-like immunoreactive (visinin-IR) structures in the cerebellum and vestibular nuclei of the rat brain was examined by indirect immunofluorescence. Visinin-IR structures are localized exclusively in the Purkinje cell system in these areas. Immunoreactive Purkinje cells first appear at gestational day 18, increasing in number with age. The axons appear at gestational day 19 and develop markedly until reaching the adult level at postnatal day 4. However, immunoreactive dendrites do not reach the adult pattern until postnatal day 21. In the cerebellar and vestibular nuclei, immunoreactive fibers first appeared at gestational day 18 and increased in number there with age, reaching the adult level at postnatal day 4.