Why doesn't recall take into account true negatives?

Why doesn't recall take into account true negatives? In experiments where true negatives are just as important as true positives, is their a comparable metric that does take it into account?

If you are primarily interested in finding the negatives, "True Negative Rate" (as already suggested by chl) is the way to go. But don't forget to look at a "precision for focus on negatives"-metric (i.e. $\frac{TN}{TN + FN}$, because otherwise the "True Negative Rate" can be optimized by setting the prediction to "Negative" for all data points).