Figure 5 - Cyclooxygenase or lipoxygenase inhibitors and LES basal tone.

LES circular muscle strips were incubated in the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) or the cyclooxygenase inhibitor indomethacin (Indo), alone or in the presence of tetrodotoxin (TTX) 10^-4 M. NDGA had no effect. Indomethacin caused a concentration-dependent reduction in LES basal tone that was not affected by tetrodotoxin. These data suggest that prostaglandins, and not leukotrienes, play a role in LES basal tone and that prostaglandins may not come from nerve terminals. Values are mean SE of three to seven animals. (Source: Cao et al.,¹⁵ with permission from the American Physiological Society.)