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Biomedical subjects

F Kawakami

Publications and source records attributed to F Kawakami.

At least 55 records · Page 3Linked to original sources
PubMed1985

The influence of serotonergic inputs on peptide neurons in the rat suprachiasmatic nucleus: an immunocytochemical study.

The influence of serotonin (5-hydroxytryptamine; 5-HT) innervation on peptide-containing neurons in the rat suprachiasmatic nucleus (SCN) was investigated by peroxidase-anti-peroxidase (PAP) immunocytochemistry. The 5-HT neuronal system was chemically severed by 5,6-dihydroxytryptamine (5,6-DHT) injection into the medial forebrain bundle bilaterally. After this treatment, a marked decrease of vasoactive intestinal peptide (VIP)-like immunoreactivity in neuronal perikarya occurred in the SCN corresponding to a decrease in number of 5-HT immunoreactive fibers and terminals. However, no alteration of arginine-vasopressin-like immunoreactivity was detected between 5,6-DHT-treated animals and the controls. It is speculated that VIP-like immunoreactive neurons play an important role in the SCN under the influence of strong 5-HT innervation.

5,6-Dihydroxytryptamine↗
PubMed1985

Light and electron microscopic immunocytochemistry of beta-endorphin/beta-LPH-like immunoreactive neurons in the arcuate nucleus and surrounding areas of the rat hypothalamus.

beta-Endorphin/beta-LPH-like immunoreactive neurons in the hypothalamic arcuate nucleus and its surrounding areas were visualized by light and electron microscopic immunocytochemistry. Immunoreactive processes were found in the vicinity of the pia mater, in the lateral part of the external layer of the median eminence and near the lateral wall of the third ventricle. Neuronal perikarya contained immunoreactive dense granules as well as developed cell organellae. They received neuronal inputs from other neurons through axoplasmic and axodendritic synapses. Immunoreactive neuronal processes containing dense granules and mitochondria were found as preterminal elements on non-immunoreactive neuronal soma and dendrites. Immunoreactive processes also make intimate contact with capillaries in the arcuate nucleus near the median eminence.

Animals↗
PubMed1984

Influence of ascending noradrenergic fibers on the neurotensin-like immunoreactive perikarya and evidence of direct projection of ascending neurotensin-like immunoreactive fibers in the rat central nucleus of the amygdala.

The influence of ascending noradrenergic neuronal input on the neurotensin (NT)-like immunoreactive neuronal perikarya located in the dorsal part of the central nucleus of the amygdala (CNA) was examined using fluorescence histochemistry and peroxidase-antiperoxidase (PAP) immunocytochemistry. Unilateral hemitransection of the ascending noradrenergic pathway by injection of 6-hydroxydopamine into the caudal mesencephalon just rostral to the locus coeruleus caused a marked depletion of immunoreactivity in NT-like immunoreactive neuronal perikarya in the CNA. Ascending noradrenergic neuronal input, therefore, is considered to facilitate production of NT-like immunoreactive substances in neuronal perikarya and to influence on the functional role of the amygdaloid complex. In addition, we obtained evidence of unilateral direct ascending projections of NT-like immunoreactive neurons into the CNA since the disappearance of NT-like immunoreactive processes occurred mainly in the ventral part of the CNA after surgical hemitransection of the ascending neuronal pathway that interrupts the ascending NT-like immunoreactive pathway arising from the neurons in the brain stem.

Amygdala↗
PubMed1984

Light and electron microscopic immunocytochemistry of neurotensin-like immunoreactive neurons in the rat hypothalamus.

Neurotensin-like immunoreactive neuronal perikarya, fibers and terminals in the rat hypothalamus, particularly in the arcuate nucleus, the paraventricular nucleus and the median eminence, were investigated by light and electron microscopic immunocytochemistry. The main distributional areas of immunoreactive neuronal perikarya were found to be the arcuate nucleus, the periventricular nucleus and the paraventricular nucleus by light microscopic immunocytochemistry. Immunoreactive neuronal perikarya showed a characteristic distributional pattern in the arcuate nucleus. In the paraventricular nucleus they were distributed in both the magnocellular and parvocellular portions. A large number of immunoreactive terminals were observed throughout the external layer of the median eminence, particularly its lateral portion. A moderate number of immunoreactive terminals were also observed in the internal layer of the median eminence. By electron microscopic immunocytochemistry immunoreactive neuronal perikarya both in the arcuate and paraventricular nuclei showed generally well-developed cell organelles such as mitochondria, r-ER, and Golgi complex. In addition, immunoreactive dense granules were dispersed throughout the perikarya. A large number of immunoreactive terminals containing immunoreactive dense granules, clear vesicles and mitochondria were observed in the vicinity of pericapillary spaces of the external layer of the median eminence. This observation strongly suggests that neurotensin-like immunoreactive substance is released into the portal capillaries.

Animals↗
PubMed1984

Influence of ascending noradrenergic fibers on the neurotensin-like immunoreactive neurons in the rat paraventricular nucleus.

Regulation of the neurotensin (NT)-producing neurons by ascending catecholamine fibers in the paraventricular nucleus of the rat hypothalamus was examined using fluorescence histochemistry and immunohistochemistry after the destruction of the ascending catecholamine pathway by 6-hydroxydopamine. On the ipsilaterally operated side, the fluorescence of the catecholamine terminals decreased remarkably in the paraventricular nucleus whereas an accumulation of catecholamine fluorescence was observed in the caudal mesencephalon rostral to the locus coeruleus. In addition, the number of neural perikarya with NT-like immunoreactivity was greatly decreased in the paraventricular nucleus on the operated side compared with the intact side as determined by peroxidase-antiperoxidase immunohistochemistry. This decrease in the NT-like immunoreactive neural perikarya may be due to the disappearance of noradrenergic input to the NT-like immunoreactive neurons through axo-somatic or axo-dendritic synapses.

Adrenergic Fibers↗
PubMed1984

The free vascularized sural nerve graft.

The sural nerve was described as a new donor nerve of the free vascularized nerve graft in a fresh cadaver's dissection and in four clinical cases. The vascularized sural nerve is nourished by the cutaneous branch of the peroneal artery or the muscular perforating branch of the posterior tibial artery in our grafts. Compared to other vascularized nerve grafts, the sural nerve has many advantages: 1) A "two- or three-fold nerve graft" can be designed on itself without damage to the blood supply of the nerve, 2) survival of the nerve can be reasoned by the accompanying flap and the flap can close the skin defect simultaneously without additional vascular anastomosis, and 3) sensory loss at the donor site is negligible. The final extent of sensory recovery in our clinical cases could require several months, but a quickly advanced Tinel's sign suggested the technique's superiority.

Adult↗
PubMed1984

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.

Animals↗
PubMed1984

New application of catecholamine fluorescence histochemistry using glyoxylic acid for diagnosis of Hirschsprung's disease by rectal biopsy.

Catecholaminergic innervation was studied in the rectal biopsy specimen obtained from patients with Hirschsprung's disease. The histofluorescence of catecholamine was examined using glyoxylic acid and magnesium without freeze-drying. Aganglionic specimens exhibited no fluorescent network of terminals or fibres in the submucosal plexus, whereas ganglionic specimens showed ganglion cells surrounded by a network of catecholaminergic terminals and fibres. These results of rectal biopsy could be obtained easily and quickly with good reliability. Examination of the catecholaminergic innervation by this histofluorescence method provides a new approach to the diagnosis of Hirschsprung's disease.

Adrenergic Fibers↗
PubMed1981

Presence of ACTH-potentiating factors in rat anterior pituitary glands.

High molecular weight ACTH fractions, obtained through gel filtration of boiled rat anterior pituitary extract, induced a marked increase in corticosterone production from isolated rat adrenal cells in the presence of low concentrations of ACTH-(1-24). This indicates the presence of heat-stable factors augmenting the steroidogenic action of ACTH in the rat anterior pituitary. We also noted that these factors potentiated the activity not only of ACTH-1(1-24) but also of ACTH-(1-8). The ACTH-potentiating factors in rat anterior pituitary extract are possibly present in heterogeneous forms according to their molecular weights (8,000, 10,000 and 15,000), their mobility in ion-exchange chromatography and their content in RIA-ACTH activity. Of these three forms, the former comigrated with biological ACTH activity. The remaining two forms were free of it. Since the effect of potentiating factors on modified ACTH-(1-9), shown to be less susceptible to proteolytic degradation from ACTH-(1-24), was similar to the effect on ACTH-(1-24), it is suggested that potentiation was not due to an inhibition of ACTH proteolysis.

Adrenal Glands↗
PubMed1981

Changes in distribution of molecular weight forms of biologically active and immunoreactive adrenocorticotropic hormone after adrenalectomy in rat anterior pituitary.

The concentration of ACTH in extracts of rat anterior pituitary was measured by both radioimmunoassay and bioassay at different stages following adrenalectomy. Both types of ACTH activity decreased the day immediately following adrenalectomy but increased gradually afterwards. Immunological ACTH activity increased to 250% of the control value and biological ACTH activity increased to 490% of control value 3 weeks after adrenalectomy. The increase in biological ACTH activity occurred earlier, and the rate of increase was greater, than that of the immunological ACTH activity. The distributions of molecular weight forms of ACTH in extracts of anterior pituitary lobes was determined by gel filtration. Three molecular weight forms of immunoassayable ACTH were detected. Biological ACTH activity appeared in the 2nd and the 3rd peaks. A striking change was observed after adrenalectomy in the distribution of biologically active forms of ACTH. The ratio of biological ACTH activity to immunological ACTH activity in each peak changed at various stages after adrenalectomy. This indicated the heterogenous nature of the ACTH included in each peak. At 2 and again at 3 weeks, biological activity markedly increased until it exceeded the immunological ACTH activity in the 2nd peak. Dexamethasone had little influence on the elution profile of either immunoassayable and biologically active ACTH in gel filtration. Adrenalectomy may possibly have an effect on the intracellular posttranslational processing of ACTH precursors which leads to the development of biological ACTH activity.

Adrenalectomy↗