New norsesquiterpene aldehyde and sesquiterpene hemiacetal from the seed ofPolygonum hydropiper

Summary A new norsesquiterpene aldehyde, polygonal and a new sesquiterpene hemiacetal, isodrimeninol having drimane skeleton have been isolated from the seed ofPolygonum hydropiper, and their structures have been established to be1 and5. Polygonal showed pungency and plant growth inhibitory activity.     

Changes in the activities of protein kinase modulators in the cerebellum of mice due to ethanol, caffeine, or phenobarbital administration.

Decreased activities of both the inhibitory modulator of adenosine 3':5'-monophosphate (cAMP)-dependent protein kinase (A-PK) as well as the stimulatory modulator of guanosine 3':5'-monophosphate (cGMP)-dependent protein kinase (G-PK) from the mouse cerebellum were noted due to the administration of excessive doses of ethanol, caffeine, and phenobarbital for up to 28 days. The dose-dependent of the inhibition of A-PK or the stimulation of G-PK was observed as a function of the amount of protein kinase modulators in the cerebellum of mice receiving different doses of ethanol.     

Receptor potential of rat taste cell to potassium benzoate.

Rat taste cells responded to relatively low concentrations of K-benzoate with a hyperpolarization and to the high concentrations with a depolarization. During both responses the membrane resistance of a taste cell decreased. Depolarization elicited by application of a combination of 0.25 M NaCl and 0.05 M K-benzoate was smaller than that by the NaCl alone, indicating a depressant action of K-benzoate.     

Alternative methods of animal sacrifice: The effect on intestinal function in vitro

Summary The total fluid uptake of everted sacs of rat jejunum was compared in animals killed by stunning and decapitation, or anaesthetised with ether. Fluid transport was significantly higher in the tissue prepared from stunned and decapitated animals. It is suggested that etherization may have adverse effects on the physiological viability of subsequently isolated tissues.     

The loss of biological activity of 5-hydroxytryptamine creatinine sulphate

Summary 5-Hydroxytryptamine creatinine sulphate loses its biological activity when maintained at room temperature. The loss of 5-HT activity (in stimulating sodium transport across frog skin) is greater than the loss of creatinine sulphate activity (inhibition of sodium transport).     

Thiamine triphosphate metabolism and its turnover in the rat liver

Summary When rats were injected with a thiamine disulfide derivative, the content of thiamine triphosphate (TTP) in the liver doubled within 3 h after a preceeding rise in thiamine pyrophosphate; it then returned to the basal level within the next 3h, indicating a net increase of TTP in vivo and its rapid turnover.     

Immunopetentiators and the protection they give against carbon tetrachloride hepatotoxicity

Summary Immunopotentiators such as BCG, levamisole, PS-K and OK-432 prevent carbon tetrachloride (CCl₄) hepatotoxicity, and in spite of exposure to CCl₄ the liver tissue levels of thiobarbituric acid (TBA) reactive substances were not increased in rats pretreated with such immunopotentiators.