. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Summed Data lead no change extension. ID Feeding Data 0 Pb-ppm Figure 1. Summary data of lead effects on Hermissenda associative learning and feeding: A. Graph of three experiments of "Hermissenda exposed to lead ( ppm), trained and tested for learning response: foot contraction, positive learning acquisition: no response or foot exten- sion, no learning (n = 43). B. Graph of responses of control animals kept in (NSW), trained and tested as in A (n = 56). C. Graph oj summed experimental data A C/u-S
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Summed Data lead no change extension. ID Feeding Data 0 Pb-ppm Figure 1. Summary data of lead effects on Hermissenda associative learning and feeding: A. Graph of three experiments of "Hermissenda exposed to lead ( ppm), trained and tested for learning response: foot contraction, positive learning acquisition: no response or foot exten- sion, no learning (n = 43). B. Graph of responses of control animals kept in (NSW), trained and tested as in A (n = 56). C. Graph oj summed experimental data A C/u-Saiiare value oj JO. / 9 with aprob- abilitv of< was obtained between lead and no-lead (df = 2). D Graph of the percentage of Tubularia po/y/w consumed over a three-day period hy Hermissenda exposed to 0. I, 3. and 6 ppm lead (n = 9/group) illustrating a marked feeding inhibition above 3 ppm. Ancillary to this study we found that feeding in Hermissenda exposed to lead above 3 ppm is depressed (94% of Tubulariu polyps consumed at 0,1,3 ppm, n = 27; of polyps consumed at 6 ppm, n = 9; Fig. 1 D). Feeding is also regulated by serotonin and can be similarly depressed by its toxic analog, 5,7-dihydroxytryptamine (5,7-DHT) (12). Lead interferes with neurotransmitter synthesis, serotonin (5-HT) and GABA in particular (14, 15). 5-HT is known to modulate long-term memory in Ap/ysia (9) and, with GABA, conditioning responses in Hermissenda (10,11). Therefore an ap- proach to studying the neurotoxic effects of lead on Hermissenda learning might be through the synthesis of neurohormones like se- rotonin and GABA and their neuromodulatory pathways. These studies would be enhanced if coupled with pharmacological exper- iments using therapeutic lead chelators such as sodium 2,3-dimer- captopropane-1-sulphonate (DMPS) and meso-2,3-dimercapto- succinic acid (DMSA)( 13). Hermissenda appears to have excellent potential for use as a non-mammalian model for lead toxicity. This research
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
