Response: Mediation of Interactions Among Insect Herbivores

1986 Science  
of other researchers when the correct comparisons are made, that is, those which take into account differences between the volatile anesthetic agents and the means by which they are administered. The conflict arises when a random comparison of results is made. Another point brought up by Strum et al. concerns the spatial origin of the fluorine-19 signal observed in our NMR experiments. Strum et al. suggest that "the focus of the NMR surface coil may have provided images of isoflurane in fat
more » ... er than brain." It is important to note that the data we have reported are based upon fluorine-19 spectra obtained with a surface coil, and are not from NMR images. These and other studies (7) in our laboratory using fluorine-19 rotating-frame zeugmatography, imaging, and spatially localized relaxation time methods indicate that the region sampled is indeed within the brain. These results were corroborated by in vitro experiments on isoflurane and halothane distribution in brain and other tissues. The data of Strum et al. show longer retention times in fat than in brain or muscle, which agrees with our own results. Thus, they report for isoflurane in fat a decrease of 60% at 270 minutes, whereas we observe in that time an 85% decrease in brain concentration (8). The loss of isoflurane we reported is greater than the loss reported for fat by Strum et al. Therefore, it would be difficult to conclude that our detected NMR signal originated from fatty tissues.
doi:10.1126/science.234.4783.1588-a pmid:17816509 fatcat:72aree3l4fbplf2lcbaqbq7wzi