. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 426 C. G. DUFORT ET AL. some cases, data were also recorded on an AstroMed Dash 4 polygraph (Grass Instruments, Quincy, MA). Lobsters were placed individually in a 3-1 light-tight acrylic plastic chamber that was continuously perfused with cooled (12 to 14 °C) normal seawater taken from a large holding aquarium. The experimental chamber was con- nected by tubing to two 1-1 stimulus bottles, one containing experimental (0 ppt) water, and the other containing control seawater (32 ppt). Valves were used to control whether the l
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 426 C. G. DUFORT ET AL. some cases, data were also recorded on an AstroMed Dash 4 polygraph (Grass Instruments, Quincy, MA). Lobsters were placed individually in a 3-1 light-tight acrylic plastic chamber that was continuously perfused with cooled (12 to 14 °C) normal seawater taken from a large holding aquarium. The experimental chamber was con- nected by tubing to two 1-1 stimulus bottles, one containing experimental (0 ppt) water, and the other containing control seawater (32 ppt). Valves were used to control whether the lobster received an experimental or a control stimulus. Dur- ing the ion-sensitivity experiments (see subsequent section of Materials and Methods), the experimental water con- sisted of solutions that were isotonic to the seawater in the recording chamber (950-1050 mOsm) but deficient in one or more specific ions. The temperature of the water in the stimulus bottles was held constant by placing them in a 25-1 water bath that was maintained at the same temperature as the chamber holding the lobster. Lobsters were secured in the chamber with elastic bands fastened loosely across their dorsal carapace and left over- night to adjust to this new environment. Previous studies have indicated that cardiac responses are more pronounced and are elicited with smaller stimulus intensities when lob- sters are left in the chamber overnight instead of being tested shortly after electrode implantation (Offutt, 1970; Florey and Kriebel, 1974; Jury and Watson, 2000). All lobsters were first tested to determine whether their heart rates altered in response to tactile stimulation, 10 betaine (Atema and Voigt, 1995). or shadows (Larimer, 1964). Only lobsters that exhibited a cardiac response to these stimuli were used in subsequent experiments. A Quicktime video showing a lobster cardiac response to a low-salinity stimulus can be viewed at the following web- site:
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
