Hisaki Kamo

Descending projections of the basal forebrain in the rat demonstrated by the anterograde neural tracer Phaseolus vulgaris leucoagglutinin (PHA-L)

Descending pathways from the mediobasal forebrain were studied in the rat by injecting anterograde axonal tracer Phaseolus vulgaris leucoagglutinin into the substantia innominata and diagonal band of Broca. From both areas, positive fibers which varied in density were observed in the mediodorsal and ventral parts of the ventroposterior and ventromedial thalamic nuclei, the lateral habenula, the stria medullaris, the lateral hypothalamus and the ventral tegmental area. This descending complex appeared predominantly course through the medial forebrain bundle from which positive fibers ramified into the fasciculus thalamicus to distribute in the thalamic nuclei. A minor descending pathway through the stria medullaris was also noted which terminated in the lateral habenula and the mediodorsal thalamic nucleus. An obvious difference in terminal distribution in the medial habenula, mediodorsal thalamic nucleus and pons could be observed following substantia innominata or diagonal band injection.

A distinctive distribution of reactive astroglia in the precentral cortex in amyotrophic lateral sclerosis

SummaryMorphological changes in astrocytes have been studied in the primary motor cortex of persons dying with or without amyotrophic lateral sclerosis (ALS). Glial fibrillary acidic protein (GFAP) and S-100 protein were used as immunohistochemical markers for reactive astroglia. In 12 brains of individuals without neurological disease glial cells showing moderate immunoreactivity for both GFAP and S-100 protein were uniformly distributed in the primary motor cortex in the upper regions of layer I and layer II. In 8 of 11 ALS cases, intensely immunoreactive cells were additionally found to occur and were scattered irregularly, mostly in layers II and III, but occasionally in layers IV and V. Clusters of these intensely positive cells occurred in patches about 200–400 μm in diameter, each containing about 6 to >20 such cells. GFAP-positive astrocytes were seen in some of the 36 brains from persons with neurological problems other than ALS but the pattern was different. The abnormal appearance of clusters of positive astrocytes of the primary motor cortex may be intimately associated with the ALS disease process.

Induction of c-Fos-like protein in the lateral habenular nucleus by persistent noxious peripheral stimulation

Persistent noxious peripheral stimulation by formalin injection into the unilateral hindpad of anaesthetized rats induced c-Fos-like protein immunoreactivity (c-Fos-LI) in neurons within the lateral habenular nucleus (LHb) bilaterally. Formalin injection after the transection of spinal cords also induced c-Fos-LI in many neurons within the LHb, though the number of labeled cells changed depending on the post-transection period. These results suggest that the LHb modulates nociceptive information, but that it receives nociceptive information via extraspinal pathways as well as intraspinal ascending noxious pathways.

Neovascularization in kainic acid-induced lesions of rat striatum. An immunohistochemical study with laminin

Vascular changes occurring after stereotaxic injection of the excitatory neurotoxin kainic acid (KA) into the rat striatum were studied at various time intervals after the lesion using laminin immunohistochemistry. Laminin immunohistochemistry revealed marked vascular changes, including presumed neovascularization, in the lesioned striatum. Vessels with increased laminin immunoreactivity were demonstrated from 2 days up to at least 5 months following the injection. The majority was capillary vasculature, which was distributed throughout the lesioned striatum, sometimes being arranged densely along the needle tract. Fine spike-like sprouts called streamers were also loaded with laminin immunoreactivity. In contrast, laminin immunoreactivity in vessels in the control striatum was negligible. Vascular changes detected by laminin immunohistochemistry preceded but then almost paralleled gliosis demonstrated by glial fibrillary acidic protein immunohistochemistry. These results indicate that striatal injection of KA causes marked vascular changes including neovascularizations which are demonstrable by laminin immunohistochemistry.

An economic anterograde axonal tracing method using Phaseolus vulgaris agglutinin (PHA) P-form

Phaseolus vulgaris leucoagglutinin (PHA-L) has been demonstrated to be an excellent neuroanatomical anterograde tracer. So far there are relatively few applications of this technique, mainly due to the cost of the lectin. Instead of PHA-L, we have successfully used PHA-P, which is a crude and inexpensive form of PHA-L. The sensitivity of the present method, examined in the rat striatonigral pathway, is as high as that of the conventional method. Furthermore, a large amount of PHA-P, injected into the cat eye, demonstrated the retinofugal projection in detail.

Soybean agglutinin binds commonly to a subpopulation of small-diameter neurons in dorsal root ganglion, vascular endothelium and microglia in human spinal cord

Soybean agglutinin (SBA) was used to identify the location of N-acetylgalactosaminyl glycoconjugates in human dorsal root ganglia (DRG) and spinal cord. SBA bound to a subpopulation of small-diameter neurons in DRG and their central projections. It also bound to microglia and vascular endothelium. Vascular endothelium, DRG neurons and microglia do not originate from the neural tube, but penetrate into the neural tube in the embryonic stage and thereafter are located in the spinal cord. SBA binding glycoconjugates may be responsible for cell-cell interaction between these three cell types and tissues in human spinal cord.

Monoamine oxidase-containing nerve fibers in the major cerebral arteries of rats

The localization of monoamine oxidase (MAO) in nerve fibers associated with the major cerebral arteries in rats was studied using a new coupled peroxidation method modified by adding nickel ammonium sulfate at the electron microscopic level. MAO was, localized in some unmyelinated axons, both in the adventitia and in the periadventitial nerve bundles. Schwann cell cytoplasm encircling myelinated axons in the periadventitial nerve bundles also contained a MAO-reactive substance. The incidences of MAO-containing axons in the adventitial layer of the anterior cerebral, middle cerebral, internal carotid and basilar arteries were 32.3%, 29.5%, 29.6% and 21.1%, respectively. In the periadventitial nerve bundles, MAO activity was also demonstrated in 10.8% among unmyelinated axons. Preincubation with clorgyline, a specific inhibitor of MAOA, suppressed staining in the axons, both in adventitia and in periadventitial nerve bundles, but not in the Schwann cell cytoplasm. Conversely, preincubation with deprenyl, a specific inhibitor of MAOB, suppressed staining in the Schwann cell cytoplasm, but not in the axons. Therefore, MAO in the axons is regarded as MAOA and MAO in the Schwann cell cytoplasm as MAOB. In immunosympathectomized rats (anti-NGF-treated rats), MAO reactivity was suppressed in axons associated with cerebral arteries, but was retained in some Schwann cell cytoplasm. The results indicate that the MAO-containing unmyelinated axons coincide with the postganglionic noradrenergic ones. Thus, histochemical MAO staining may be utilized to study postganglionic sympathetic nerve fibers presumably innervating the major cerebral arteries at the electron microscopic level.

Ulex europaeus I and glycine max bind to the human olfactory bulb.

The distribution of binding sites for the fucose-selective lectin Ulex europaeus I and the terminal N-acetylgalactosamine-selective lectin glycine max in the human olfactory bulb were studied. These lectins bound to primary olfactory axons in the olfactory nerve layer and the glomerular layer. They also bound to fibers located in the deeper layers such as the external plexiform layer and the granular layer. Furthermore they projected to the olfactory stalk but not in the cerebrum. The deeper projections of the lectin binding fibers may affect the function of the olfactory bulb in humans.

DIFFERENTIAL LOCALIZATION OF LECTIN BINDING SITES AND NEUROPEPTIDES IN HUMAN DORSAL ROOT GANGLIA

The subpopulations were compared of neurons in human dorsal root ganglia (DRG), as substance P, identified by somatostatin, Glycine max lectin (SBA) specific to terminal N-acetylgalactosamine, and Ulex europaeus I agglutinin (UEA-I) specific to l-fucose. The lectins and neuropeptides all bound to neurons of small diameter. Furthermore, the majority of the SBA binding neurons or somatostatin positive neurons were also UEA-I binding neurons. However, SBA binding neurons were not colocalized with somatostatin or substance P. Less than 20% of substance P positive neurons showed colocalization with l-fucosyl residues, and approximately 10% of l-fucosyl residues showed colocalization with substance P. Our results suggest that both l-fucose and terminal N-acetylgalactosamine containing neurons in the human DRG are subjected to different subpopulations from substance P or somatostatin positive neurons.

A computer support system for neurological anatomical diagnosis

OBJECTIVES Accurate neurological diagnoses are often difficult to make due to the complexity of the neuroanatomy involved. This study was performed to evaluate the usefulness of a computer system with easily retrievable anatomical information as a support for arriving at more accurate anatomic diagnoses. PATIENTS AND METHODS Anatomical information from an initial physical examination was programmed into a computer with stored neuroanatomical charts of the brain, spinal cord and peripheral nerves. The information generated a graphic display of possible lesions with suggestions for further examination. These suggestions were then followed and further data entered. This data entry generated a new graphic display with reduced lesion possibilities. Iterations were then followed to narrow the possibilities for diagnosis further, until a final anatomical diagnosis was reached. This method was applied to three hypothetical examples and a number of clinical cases. Here we report three clinical cases in which this method was particularly useful in making a diagnosis. RESULTS Using computer iterations, the system was able to pinpoint one or more presumptive causative lesions in the CNS or PNS based on known neuronal pathways or nuclei. CONCLUSION The results indicate that suitably used, computer memory, by virtue of its large capacity, accuracy and fast recall, can supplement human memory in reaching accurate anatomical diagnoses of neurological lesions.