Terubayashi H

Vasoactive intestinal peptide (VIP)-like immunoreactive neurons located in the rat suprachiasmatic nucleus receive a direct retinal projection.

The existence of a direct projection from retinal ganglion cells to vasoactive intestinal peptide (VIP)-like immunoreactive neuronal elements in the rat suprachiasmatic nucleus (SCN) was revealed by combining analysis of degenerating axons following enucleation and electron microscopic immunocytochemistry. Degenerating axons appeared to make synaptic contact with VIP-like immunoreactive dendrite and neuronal perikarya in the ventral part of the SCN. The possibility of neuronal input from retinal ganglion cells to axons of VIP-like immunoreactive neurons was also suspected since axo-axonic synapses were detected between degenerating axons and axons with VIP-like immunoreactivity. Thus, VIP-like immunoreactive neurons in the SCN receive several neuronal inputs, including those from the retina, and may play a significant role in circadian entrainment.

Coexistence of dopamine and neurotensin in hypothalamic arcuate and periventricular neurons

The coexistence of dopamine and neurotensin in the same neuronal perikarya in the arcuate nucleus of the rat hypothalamus was examined by combined fluorescence histochemistry and immunohistochemistry on the same tissue sections and we obtained the evidence of the coexistence of two substances. The functional significance of those two substances for the prolactin release from the anterior pituitary was also briefly discussed.

Immunohistochemical investigations of gut hormones in the colon of patients with Hirschsprung's disease*

The distributions of gut hormones in the colon of Hirschsprungs disease were investigated by the peroxidase-antiperoxidase (PAP) immunohistochemical method. Three colonic segments (ganglionic, oligoganglionic, and aganglionic) were stained by the unlabeled antibody enzyme method. The immunoreactivity of vasoactive intestinal polypeptide (VIP) was found to be reduced in the oligoganglionic and aganglionic segments. Antisera to substance P and met-enkephalin demonstrated immunoreactive cells and fibers in the ganglionic segment, whereas these cells and fibers were almost completely absent in the oligoganglionic and aganglionic segments. A similar distribution was seen for the mucosal endocrine cells with somatostatin immunoreactivity. Antisera to neurotensin, motilin, bombesin, and cholecystokinin revealed no immunoreactivity in the normal colon or the three segments. The differences in these peptides between normal and impaired colonal segments may be one of the causes of colon constriction in Hirschsprungs disease.

Distribution of the VIP-like immunoreactive neurons in the cat central nervous system ☆

Immunohistochemical topographic localization of the vasoactive intestinal polypeptide (VIP)-like immunoreactive neurons in the cat brain was investigated using a peroxidase anti-peroxidase technique. VIP-like immunoreactive neurons were mainly localized in the cerebral cortex, limbic cortex, hypothalamic nuclei; suprachiasmatic nucleus, supraoptic nucleus, paraventricular nucleus, periventricular nucleus and arcuate nucleus, and in the midbrain; such as the central grey and the raphe nucleus. It was demonstrated that VIP-like immunoreactive neurons were widely distributed in the cat brain, particularly in the hypothalamus, compared with those of the rat and mouse; though whether these differences were species-related or due to differences in the physiological conditions remains to be determined. This is the first report of VIP neuronal perikarya in the arcuate nucleus of mammalian species, although these cells are present in the arcuate nucleus of birds.

An immunohistochemical investigation of vasoactive intestinal polypeptide in the colon of patients with Hirschsprung's disease.

The distribution of vasoactive intestinal polypeptide (VIP) in the colon of patients with Hirschsprungs disease was investigated by the peroxidase-antiperoxidase (PAP) immunohistochemical method. Three colonic segments, ganglionic, oligoganglionic and aganglionic, were stained by the unlabeled antibody enzyme method. VIP immunoreactive nerve cell bodies, nerve fibers and nerve endings were distributed throughout the ganglionic and oligoganglionic segments. In contrast, the aganglionic segment contained no VIP nerve endings and the number of fibers was reduced. These differences are thought to be a cause of constriction of the colon in Hirschsprungs disease and VIP neurons are therefore believed to participate in the relaxation of smooth muscle.

Time of vasopressin neuron origin in the mouse hypothalamus: examination by combined technique of immunocytochemistry and [3H]thymidine autoradiography

A time-course study on production of vasopressin neurons (VP-neurons) in the mouse hypothalamus was carried out by application of [3H]thymidine autoradiography and PAP-immunocytochemistry simultaneously on the same tissue sections. In the paraventricular nucleus (PVN) and the supraoptic nucleus (SON), heavily [3H]thymidine-labeled VP-neurons were detected only in the specimens of the animals exposed to the isotope on the gestational day 12. While in the suprachiasmatic nucleus (SCN), heavily isotope-labeled VP-neurons were observed in the specimens of the animals exposed to the isotope on the gestational day 12 or day 14. Therefore, the production of the VP-neurons in the SCN is prolonged and slightly more delayed than that in the SON or PVN.

Hypothalamo-retinal centrifugal projection in the dog

Horseradish peroxidase (HRP)-filled neurons and their processes were consistently detected in the ventral portion of the dog hypothalamus after intraocular injection of HRP. The number of HRP-filled neurons decreased in parallel with the extent of the resection of the optic nerve. HRP-filled neurons were never detected in specimens with a complete resection of the optic nerve. These findings strongly indicate that these HRP-filled neurons in the ventral hypothalamus are the source of centrifugal fibers to the retina.

Morphological survey of neurotensin-like immunoreactive neurons in the hypothalamus ☆

Neurotensin-like immunoreactive neuronal perikarya, fibers and terminals in in the rat hypothalamus were investigated by light and electron microscopic immunocytochemistry. Distributional density and pattern of these elements were clarified. Fine structure of immunoreactive neuronal perikarya with respect to development of cell organellae and immunoreactive dense granules was also elucidated. Features of immunoreactive processes, dendrites and preterminal axons were examined electron microscopically. In addition to the above findings by light and electron microscopic immunocytochemistry, we examined the coexistence of dopamine and neurotensin-like immunoreactive substances in these same neurons in the arcuate and periventricular nuclei. This was proved by the application of fluorescence histochemistry and immunocytochemistry on the same sections. Moreover, we speculated that the ascending noradrenergic neurons influence the neurotensin immunoreactive neurons in the paraventricular nucleus since a marked decrease in the number of neurotensin-like immunoreactive neuronal perikarya was observed after transection of ascending noradrenergic pathway.

Enzymhistochemical identification of microglial cells in the rat retina: Light and electron microscopic studies

We used the method of thiamine pyrophosphatase (TPPase) enzyme histochemistry and flat-mounted and transverse-sectioned retinas to identify microglial cells. Light microscopically, TPPase activity was demonstrated on the outer surfaces of glial cells located in the inner plexiform layer (IPL) and the ganglion cell layer (GCL) of the entire retinal regions, and also on the outer surfaces of blood vessels. Electron microscopically, TPPase activity was observed on the plasma membranes of the glial cells, the endothelial cells of microvessels and the pericytes. The TPPase-positive glial cells had a dark nucleus with large clumps of chromatin beneath the nuclear envelope. These findings strongly suggest that the glial cells with TPPase activity observed in the IPL and the GCL of the rat retina were microglial cells.

Postnatal development of vasoactive intestinal polypeptide immunoreactive amacrine cells in the rat retina.

The ontogenic development of vasoactive intestinal polypeptide (VIP)-immunoreactive amacrine cells in the rat retina was studied using peroxidase-antiperoxidase (PAP) immunohistochemistry. In the rat retina, VIP immunoreactivity appeared entirely in postnatal stage. On the 12th postnatal day, VIP-immunoreactive amacrine cells could be first detected. However, VIP immunoreactivity was very weak and VIP-immunoreactive amacrine cell processes could not be observed at this stage. On the 21st postnatal day, VIP-immunoreactive amacrine cell bodies became more mature and their processes were distinctly observed, resembling their appearance in adult rat retinas. VIP immunoreactivity could be detected in both stratified and diffuse amacrine cells at this stage. The relationship between the first appearance of VIP-immunoreactive amacrine cells and the synaptic formation in the inner plexiform layer is briefly discussed.