Nobuyasu Takeuchi

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Metalloproteinases produced by connective tissue cells may play a key part in the destruction of joints in rheumatoid arthritis. Matrix metalloproteinase 3 (MMP-3; stromelysin) capable of degrading cartilage proteoglycans and type IX collagen and of activating procollagenase was immunolocalised in hyperplastic synovial lining cells in rheumatoid synovium,(More)
The effects of serotonin (5-HT) on plasma glucose levels were studied. 5-HT above 20 mg/kg induced apparent hypoglycemia in mice. The hypoglycemic effects of 5-HT were strongly antagonized by methysergide but only partially inhibited by ketanserin. However, ICS 205-930 was without effect. This indicates that the hypoglycemia induced by 5-HT is mediated by(More)
The effects of an indoleamine, tryptamine, on plasma glucagon levels were investigated in mice. Tryptamine induced dose-related increases in plasma glucagon levels. The hyperglucagonemia effects of tryptamine were completely antagonized by methysergide and ketanserin which have a high affinity to 5-HT2 receptors. In addition, the peripheral 5-HT2 receptor(More)
The effects of tryptamine on serum insulin levels were investigated. Tryptamine induced an apparent increase in serum insulin levels in mice. The elevation in insulin elicited by tryptamine was potently antagonized by the 5-HT1 and 5-HT2 receptor antagonist, methysergide, but partially reduced by the 5-HT2 receptor antagonist, ketanserin. However, the 5-HT3(More)
We pharmacokinetically examined the effect of gamma-butyrobetaine, a precursor of L-carnitine, on the change of fatty acid metabolism in juvenile visceral steatosis (JVS) mice, which have systemic L-carnitine deficiency due to lack of L-carnitine transporter activity. The concentrations of total free fatty acid (FFA), palmitic acid and stearic acid in the(More)
Effects of serotonin (5-HT) on plasma glucose and serum insulin levels were studied in mice. In normal mice, 5-HT induced a dose-dependent hypoglycemia and an increase in serum insulin levels. 5-HT significantly inhibited glucose-induced hyperglycemia and increased glucose-stimulated insulin release. However, in streptozotocin-induced diabetic mice, 5-HT(More)
To better understand the molecular mechanisms of the previously described cardiostimulatory action of the phosphodiesterase type-5 (PDE5) inhibitor sildenafil, we first evaluated its effects on cyclic AMP level in the canine ventricular membrane preparation. Sildenafil (10 micromol/L) significantly increased the net cyclic AMP production rate, the potency(More)
Peripherally administered serotonin (5-HT) induced a marked increase in the plasma glucagon level in mice. The hyperglucagonemic effects of 5-HT were completely antagonized by methysergide, ketanserin and ritanserin which have a high affinity for 5-HT2 receptors. However, the 5-HT3 receptor antagonist ICS 205-930 and MDL 72222 were without effect. These(More)