. The Biological bulletin. Biology; Zoology; Marine biology. 5 10 15 20 time (h) 30 Figure 3. Creep curves from loading test of tooth. Curves from pull tests (A) and push tests (B) have similar shape. Upper right end of each curve indicates the point at which the tooth was pulled out of the Ugament. ligament failed. The average creep rate in the constant second phase was iiml\\ (SD , n = 36). Relative viscosity was defined as the reciprocal of creep rate, with the value just before application of a test solution taken as unity. Controls were push tests and tests with frozen jaws. In pus
. The Biological bulletin. Biology; Zoology; Marine biology. 5 10 15 20 time (h) 30 Figure 3. Creep curves from loading test of tooth. Curves from pull tests (A) and push tests (B) have similar shape. Upper right end of each curve indicates the point at which the tooth was pulled out of the Ugament. ligament failed. The average creep rate in the constant second phase was iiml\\ (SD , n = 36). Relative viscosity was defined as the reciprocal of creep rate, with the value just before application of a test solution taken as unity. Controls were push tests and tests with frozen jaws. In push tests we observed no significant differences from pull tests. The creep curves were similar (Fig. 3B). Experi- mental time until the tooth was pushed out was 17 to 97 h. The tooth had shifted 460 ^m (SD 170, n = 6) until failure. The creep rates during the second phase were of the same order as in pull tests. Freezing and rethawing of the preparations did not change the shape of the creep curves or the creep rates. Shift until failure in pull tests was 820 ^lm (SD 410, « = 4) and in push tests was 430 nm (SD 160, « = 7). Responses to stimuli Acetylcholine (ACh) caused a decrease in creep rate (Fig. 4A); , the ligament stiffened. In 17 out of 23 tests. relative viscosity doubled in 15 min (see Fig. 6). The effect was reversible: the creep rate recovered in about 1 h after washing with artificial seawater. Treatment with artificial seawater containing 100 mM K^ (KASW) also stiffened the ligament (Fig. 5A). Relative viscosity doubled in 15 minutes in 6 out of 8 tests. This effect, too, was re- versible. Push tests showed no difference in response to stimuli. ACh caused stiffening of the ligament. In two of three cases, relative viscosity increased more than 10-fold (Fig. 6). KASW caused increase of relative viscosity in all three cases—in two of them more than sixfold (Fig. 6). In extreme cases stimulation stopped movement of the tooth; , the ligament did not creep u
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