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Biomedical subjects

K Takagi

Publications and source records attributed to K Takagi.

At least 901 records · Page 50Linked to original sources
PubMed1975

Actions of bile salts and of papaverine and intracellular cyclic AMP in isolated rat uterus.

Both antioxytocin and antiphosphodiesterase activities of desoxycholate were potentiated by lowering the pH of the medium. The results suggest the possibility that it is the bile salt in the non-ionized form which exerts the antioxytocin and antiphosphodiesterase action. The concentration of tissue cyclic AMP was measured at different times during relaxation of the uterus. The results show a significant increase in tissue cyclic AMP concentration at a time when the muscle was just beginning to relax in response to papaverine, but not in response to chenodesoxycholate. The intracellular level of cyclic AMP during relaxation of the uterus produced by papaverine or chenodesoxycholate was, however, significantly increased when relaxation was about 90% complete. The difference between the mode of action of papaverine and that of the bile salts is discussed.

Animals↗
PubMed1975

Effects of beta-adrenergic receptor blocking agents on blood pressure in conscious hypertensive rats.

The effects of beta-adrenergic receptor blocking agents administered i.v. on the blood pressure in conscious spontaneously hypertensive rats (SHR), renal hypertensive rats (RHR) and normotensive Wistar strain rats (NR) were studied. dl-Propranolol and dl-YB-2, 1 mg/kg i.v., caused a sustained rise in blood pressure in SHR and RHR. The maximum response of each beta-blocking agent after phentolamine, 10 mg/kg i.v., in SHR and RHR was significantly larger than that in NR. The potency ratio for the hypertensive activities of the 1- and d-isomers of propranolol and YB-2 was similar to the ratio of their beta-blocking activities. The pressor effects of the beta-blocking agents after phentolamine were significantly inhibited by adrenalectomy, reserpinization and pretreatment with hexamethonium. The results suggest that the pressor effect of the beta-blocking agents may be due to their beta-blocking activities and the unmasking of alpha-receptor activities of the blood vessels. Furthermore, the greater pressor effect of the agents observed in hypertensive rats is attributed to a greater activity of the sympathetic nervous system in these rats as compared to normotensive rats.

Adrenalectomy↗
PubMed1975

Antiphosphodiesterase activity and nonspecific smooth muscle relaxation tested on intestinal smooth muscles.

Mitochondrial, microsomal and soluble fractions separated from the guinea pig taenia and from the dog longitudinal smooth muscle were used as phosphodiesterase preparation. Each preparation had low and high Km values, indicating the existence of at least two kinds of phosphodiesterase. Papaverine and Aspaminol (1, 1-diphenyl-3-piperidinobutanol hydrochloride), hydralazine, caffeine Na benzoate and aminophylline were used at test drugs. Aspaminol had little inhibitory effect on phosphodiesterase. Ki value of papaverine almost equalled the concentration (M) which was necessary to produce 50% relaxation. Relaxation of the guinea pig taenia by papaverine was preceded by an increase of intracellular cyclic AMP,. Therefore, the action of papaverine is likely to be mediated by an increase in cyclic AMP, which is caused by inhibition of the phosphodiesterase-catalyzed breakdown of cyclic AMP. There was little correlation between relaxing activities of the drugs used and their antiphosphodiesterase activities. Relaxation of the smooth muscle induced by the smooth muscle relaxants excepting papaverine is not due to inhibition of phosphodiesterase.

Animals↗
PubMed1975

Effects of L-glutamine on acetylsalicylic acid-induced gastric lesions in normal and cirrhotic rats.

Cirrhosis of the liver in rats was induced by the administration of carbon tetrachloride (0.1 ml/100 g of body weight, s.c.) biweekly for 13 weeks. In the pylorus ligation preparation, acetylsalicylic acid (ASA) 100 mg/kg p.o. induced much more serious gastric damage in CC14-induced cirrhotic rats as compared with rats with a normal liver. L-glutamine 750 mg/kg p.o. prevented the ASA-induced gastric lesions in both normal and cirrhotic rats, even though the degree of the inhibition was weaker in cirrhotic rats. Gastric analysis indicated that L-glutamine 750 mg/kg p.o. markedly inhibited the gastric ionic changes (acid back diffusion) in response to ASA in both cirrhotic and normal rats.

Animals↗
PubMed1975

[Phamacological studies on bamboo grass (1). Acute toxicity and anti-inflammatory and antiulcerogenic activities of water-soluble fraction(Folin) extracted from Sasa albomarginata Makino et Shibata].

Folin showed no significant toxic effects in mice. The tail pressure test in mice revealed a potent analgesic effect with a hypothermic effect in rats. A significant decrease was also seen in rat dextran or carrageenin edema. There were no inhibitory effects on the formation of granulation tissue in rats. In addition, Folin administration revealed a tendency to a decrease in pylorus-ligated ulcer of the rat by inhibiting the gastric secretion. Some protective effects from aspirin or caffeine-induced gastric ulcers of the pylorus-ligated rats were also obtained in this fraction.

Analgesics↗
PubMed1974

The isolation of an easily reversible post-synaptic toxin from the venom of a sea snake, Laticauda semifasciata.

A weakly neurotoxic component (Ls-III) was isolated by CM-cellulose column chromatography from the venom of a sea snake Laticauda semifasciata. The content of component LsIII was about 10-20% of the venom as determined by u.v. absorption at 280nm. Component LsIII was homogeneous on rechromatography and disc electrophoresis, and its molecular weight was shown to be 7100 by ultracentrifugation and 7300 by sodium dodecyl sulphate-polyacrylamide-gel disc electrophoresis. The isoelectric point of component LsIII was pH7.2. Component LsIII consisted of 66 amino acid residues including 10 half-cystine residues. The LD(50) of component LsIII by intramuscular injection was 1.24mug/g body wt. for mice and 0.45mug/g for baby chicks, which is about eight to ten times less toxic than erabutoxins a, b and c, all of which are contained in the same venom. Experiments with three isolated muscle preparations from different species indicated that component LsIII was a post-synaptically acting toxin, the action of which was easily reversed by washing.

Acetylcholine↗