Effect of salicylate on zinc metabolism in fetal and maternal rats fed normal and zinc-deficient diets

Biological Trace Element Research - Pregnant rats fed normal and Zn-deficient diets were treated with oral daily doses of 100 and 300 mg/kg salicylic acid from d 16–20 of gestation. This...     

Stock differences in the susceptibility of rats to learned helplessness training

Learned helplessness (LH) consists of shock escape deficits evidenced by animals previously exposed to inescapable shock. This phenomenon has shown promise as a behavioral screen for new antidepressant drugs. Unfortunately, some stocks of rats evidence low susceptibility to LH training. Accordingly, male rats from 8 different stocks were tested for susceptibility to LH training. The outbred stocks consisted of Harlan SD, Sasco Holtzman, and Charles River Holtzman. The inbred stocks (i.e. strains) tested were Lewis, Wistar Kyoto, Brown Norway, Fischer F-344, and Buffalo. The Lewis, Brown Norway, Fischer and Sasco Holtzman rats were found to be virtually non-susceptible to LH training. Harlan SD and Buffalo rats evidenced intermediate susceptibilities of 28% and 33%, respectively. Kyoto and Charles River Holtzman rats were the most susceptible at 53% and 55%, respectively. No stock differences between control animals were observed. These results indicate that wide differences in susceptibility to LH training exist in rats from different stocks or suppliers and researchers should be careful to choose subjects from a susceptible stock. Charles River Holtzman and Wistar Kyoto rats appear to be very susceptible to LH training.     

Exchange between phloem and xylem during long distance transport of glutathione in spruce trees [Picea abies[Karst.] L.)

Radioactively labelled glutathione (³⁵S-GSH) was fed to a single1-year-old spruce needle on a twig girdled apical to the applicationsite. Uptake and translocation of the radiotracer were investigatedafter 3 h incubation in the light. Experiments were performedwith 4-5-year-old trees in July and October. In both sets ofexperiments 3-16% of the applied radioactivity was taken upby the needle and resulted in 54-77% export to the preferentialsinks, i.e. the current year's sprouts. Apparently, the girdleimposed apical to the application site did not hinder long distancetransport. A radial transfer of ³⁵S from the bark to the xylemtissue basal to the girdle and a redistribution from the xylemto the bark apical to the girdle was observed. This observationindicates that GSH can readily be exchanged between phloem andxylem in both directions. Basipetal transport of ³⁵S towardsthe stem was higher in October, but never exceeded 7% of totaluptake (13% of total export) of S-GSH. Preferential incorporationof the ³⁵S into protein was observed in July, whereas the mainportion of the radiolabel remained in the acid soluble fractionsof needles, bark and wood in October. Key words: Phloem-xylem interchange, long distance transport, radial transport, reduced sulphur, glutathione, spruce, Picea abies     

Enhanced ototoxicity of gentamicin and salicylate caused by Mg deficiency and Zn deficiency

In rats, Mg deficiency caused a moderate hearing loss, measured by means of evoked potentials at 10 and 20 kHz, which was repaired after refeeding a normal diet. Application of 700 mg/kg salicylic acid or injection of 5×100 mg/kg gentamicin also caused a reversible hearing loss in normally fed rats. Treatment of Zn-deficient rats with salicylic acid produced a stronger although reversible hearing loss than in normally fed salicylate-treated rats. Treatment of Mg-deficient rats with gentamicin induced a strong hearing loss that was nearly complete and irreversible in 9 of 25 rats.     

Verschmelzung der Otolithen von Sacculus und Lagena im Labyrinth einer Sardine (Clupea pilchardus Walb.)

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