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Biomedical subjects

K Shichijo

Publications and source records attributed to K Shichijo.

At least 19 recordsLinked to original sources
PubMed1991

The mechanism of low susceptibility to stress in gastric lesions of spontaneously hypertensive rats.

The mechanism of low susceptibility to stress in gastric lesion formation in spontaneously hypertensive rats (SHR) was investigated focusing on the sympathetic and parasympathetic nervous systems. In the gastric tissues of SHR, norepinephrine (NE) and dopamine (DA) contents were higher, while acetylcholine content and choline acetyltransferase activity were lower than those of Wistar-Kyoto rats (WKY). Water-immersion restraint induced gastric lesions frequently in WKY (ulcer indices : 52 +/- 7mm2) but less frequently in SHR (ulcer indices : 3 +/- 1mm2). Although NE content decreased in both SHR and WKY as a result of water-immersion restraint, it remained higher in SHR than in WKY. ACh content decreased by the procedure in WKY but not in SHR. DA content was increased by the procedure in all gastric regions of SHR. The gastric lesions induced in SHR were aggravated by pretreatment with 6-hydroxydopamine, an agent for chemical sympathectomy, following decreases of NE and DA contents. These results indicate that the relative sympathetic hyperfunction, parasympathetic hypofunction and dopaminergic mechanism in the stomach contribute to the prevention of gastric lesion formation in SHR.

Acetylcholine↗
PubMed1989

The role of the sympathetic nervous system in cysteamine-induced gastric lesions in rats.

Cysteamine.HCl, when administered subcutaneously at 350 mg/kg, consistently induced severe gastric lesions in Wistar Kyoto rats (WKY), but not in spontaneously hypertensive rats (SHR). In both WKY and SHR, visible ulcers could not be induced in the duodenum in response to cysteamine. It appears that the stomach and duodenum of SHR are resistant to cysteamine due to hyperfunctioning of the sympathetic nervous system.

Animals↗
PubMed1987

Mediator release from basophilic cells derived from cultured cord blood cells.

Mononuclear cells from human umbilical cord blood were separately cultured either in the presence of phorbol ester-phytohemagglutin-leukocyte-conditioned medium (PE-PHA-LCM) or PHA-LCM. Cells cultured in PE-PHA-LCM released histamine following calcium ionophore and compound 48/80 challenge. However, there was a similar histamine release from cells cultured in the presence of PHA-LCM following calcium ionophore but not following compound 48/80 challenge. Neutrophil chemotactic activity (NCA), recognized to be one of the markers for mast cell activation, was detected following calcium ionophore and anti-IgE challenge from the supernatant of cells cultured in the presence of PHA-LCM, suggesting unique features in the cells studied.

Basophils↗
PubMed1986

Experimental stress ulcer and gastric catecholamine contents in spontaneously hypertensive rats.

To determine the role of the sympathetic nervous system in the development of stress ulcer, we carried out experiments on spontaneously hypertensive rats (SHR) exposed to restraint and water immersion stress for 7 h. Normotensive Wistar-Kyoto rats (WKY) were used as controls. Catecholamine (CA) contents in gastric tissues, divided into mucosal and muscular layers of both antrum and corpus, were quantitated by high-performance liquid chromatographic electrochemical detection (HPLC-EC). The stress ulcer formation was much less frequently induced in SHR than in WKY. The noradrenaline (NA) contents in all regions of gastric tissues were higher in SHR than in WKY. The contents of adrenaline (A) and dopamine (DA), present in small quantities in gastric tissues showed no difference between SHR and WKY. After exposure to stress, the NA contents in mucosal and muscular layers of the gastric corpus decreased significantly in both SHR and WKY, whereas the value remained higher in the former. On the contrary, a remarkable increase of A contents (probably released from the adrenal medulla by the stress) was observed in all gastric tissues, of both SHR and WKY. Increase of the A contents in the mucosal layer was remarkable in the SHR. The DA contents increased in both strains. These results suggest that the peripheral sympathetic hyperfunction in the stomach in the SHR may have an inhibitory role in stress ulcer formation.

Animals↗