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Biomedical subjects

S Kikuchi

Publications and source records attributed to S Kikuchi.

At least 523 records · Page 29Linked to original sources
PubMed1979

Renal effects of propranolol, practolol and butoxamine in pentobarbital-anesthetized rats.

The renal effects of the beta-adrenergic blockers, propranolol, practolol and butoxamine, were examined in pentobarbital-anesthetized rats. All the beta-blockers, infused i.v., increased urine volume (V), urinary sodium excretion (UNaV) and p-aminohippuric acid clearance without change in inulin clearance. Indomethacin, an inhibitor of prostaglandin biosynthesis, did not affect the renal effects of these beta-blockers. Phentolamine abolished the renal effects of practolol, but not those of propranolol and butoxamine. Haloperidol abolished the renal effects of propranolol and butoxamine, but not those of practolol. A high correlation was found between the increased UNaV and the increased urinary phosphate excretion by butoxamine but not by propranolol and practolol. Therefore, it is suggested that alpha-adrenergic stimulation is involved in the mechanism of diuresis by practolol, a beta1-blocker, and that dopaminergic stimulation is involved in the diuresis caused by butoxamine, a beta2-blocker. Propranolol is similar to butoxamine, and partially similar to practolol.

Animals↗
PubMed1979

[Comparison of different types automatic water-supply system for mouse rearing (author's transl)].

Rearing and breeding scores were compared between groups of mice (JCL : ICR and ddN strains) raised with two different types of automatic water-supply systems; the Japanese type and the American type, using manual water-supply system as control. The mice raised with the manual water-supply system were superior in body weight gain as compared to those with two automatic water-supply systems. As to the survival rate, however, the m; anual water-supply system and the Japanese type gave better results than the American type. As to weanling rate in the breeding test, the manual water-supply system gave somewhat better result than either of the two automatic types. Accidental water leaks, which are serious problems of automatic systems, occurred frequently only when the American type was used. Only one defect of the Japanese type revealed was that it was unfavorable for mice with smaller size (e.g., young ddN mice), resulting in lower body weight gain as well as lower breeding scores.

Animals↗
PubMed1979

Effect of 1,4-dimorpholino-7-(4-hydroxyphenyl)pyrido[3,4-d]) pyridazine [DS-511(4'-OH)] on the transepithelial transport of sodium and water and the permeability to urea in the toad urinary bladder.

To elucidate the mechanism of the inhibitory action of 1,4-dimorpholino-7-phenylpyrido[3,4-d]pyridazine (DS-511) on water and sodium reabsorption at the renal tubules, the effect of DS-511 (4'-OH), which is similar in diuretic effect to but more water-soluble than DS-511, on the transepithelial transport of sodium and water and permeability to urea was studied in isolated toad urinary bladder. Application of DS-511(4'-OH) at concentrations above 2 x 10(-4) mol/l to the serosal side of the bladder depressed the transepithelial potential difference, short circuit current (SCC), and membrane conductance as well as the increased response of the SCC to arginine vasopressin (AVP) and cyclic AMP. The effect of DS-511 (4'-OH) applied to the mucosal side was delayed in onset and less pronounced. Neither serosal nor mucosal 10(-3) mol/l DS-511(4'-OH) depressed the increased response of the SCC to amphotericin B. 2 x 10(-4) mol/l DS-511 (4'-OH) applied to the serosal side did not affect osmotic water flow, but potentiated the increase in water flow caused by AVP. Basal urea permeability as well as the increase in urea permeability caused by AVP were depressed by serosal 10(-3) mol/l DS-511 (4'-OH). The results show that DS-511(4'-OH) has two actions, the depression of the transepithelial transport of sodium and urea, and the potentiation of the increased water permeability caused by AVP.

Amphotericin B↗
PubMed1978

Coronary vasospastic action of thromboxane A2 in isolated, working guinea pig hearts.

The effects of thromboxane A2 (TXA2) on isolated, working guinea pig heart and left ventricular papillary muscle preparations were investigated. TXA2 was generated by the enzymatic conversion of prostaglandin H2 (PGH2) with indomethacin-treated horse platelet microsomes (IPM). TXA2 caused dose-dependently a considerable decrease in the coronary flow, left ventricular systolic pressure and left ventricular dp/dt in the perfused heart, while the similar effects of PGH2 were transient and weaker than those of TXA2. These effects of TXA2 disappeared after the TXA2-generating system was left standing at 37 degree C for 3 min. When IPM in the TXA2-generating system was pretreated with a TXA2 synthetase inhibitor, L-8027, the enhanced cardiac responses induced by the mixture of IPM and PGH2 disappeared. TXA2 had no direct effect on the contractile force of the papillary muscle. These results suggest that TXA2 has a specific coronary vasopastic action without a direct inotropic effect.

Animals↗