A hand-operated tissue chopper

A comparison of sodium salicylate and 2:4-dinitrophenol as metabolic stimulants in vitro

“…The mean AQ02 of rat-brain slices in glucose-Ringer with mMsalicylate was found to be + 1-84; at 1-59 mm it was + 2-35, and at 6-31 x 1O-4M + 1-16. These figures are each the mean of eight observations, and approximate to those previously found for mouse-liver slices (Sproull, 1954b). An analysis of variance of these results is presented in Table 2; there was no significant departure from linear regression of AQ02 on log concentration, and therefore, since the regression coefficient is positive, unless the form of the concentration-response curve differs from that of mouse-liver slices, which as salicylate concentration increased showed increasing stimulation followed by depression (Sproull, 1954b), the effect of mM-sodium salicylate is solely stimulation, and not the resultant of a stimulation and a depression of metabolic rate.…”

“…Previous results (Sproull, 1954b) did not show a significant difference between the sexes in the response of mouse-liver slices to salicylate, but the results were not decisive. The substantial current improvement in technique, due mainly to the use of a reliable tissue chopper, improved the prospects of investigating this issue.…”

“…With mM-sodium salicylate, and glucose or pyruvate as substrate, a marked increase in oxygen consumption was found; this concentration of salicylate stimulates the metabolic rate of mouseliver slices (Sproull, 1954b). On the other hand, when succinate or oc-oxoglutarate was the substrate, mM-salicylate decreased the Qo2 Of the brain slices;…”

“…Sodium salicylate as a peripheral metabolic stimulant exhibits the outstanding pharmacological feature of 2:4-dinitrophenol (DNP) and related compounds (Sproull, 1954b). DNP inhibits oxidative phosphorylation (Loomis & Lipmann, 1948), which is considered to be the source of its metabolic stimulant property (see Simon, 1953, for review).…”

“…Liver slices. These were prepared from 3-to 8-month-old fed CBA mice, an improved chopper (Sproull, 1956) being used. The details of the manometric technique were as described above, with the exception that the mouse liver was transferred directly from the chopper to the flask without preliminary washing and separation of the slices.…”