Figure 3. Comparison of normal versus collateral-dependent vessels to increasing concentrations of isoflurane, in the absence of preconstriction. Normal vessels demonstrated a mild concentration-dependent constriction to isoflurane (P < 0.01), which was significantly greater (P < 0.05) than for the CD vessels. Constrictive response of the CD vessels to increasing concentrations of isoflurane was statistically significant (P < 0.05), but was very small in magnitude and probably physiologically unimportant. *P < 0.05 versus no effect. #P < 0.05 versus corresponding normal vessel response.