Effect of the CB-1 antagonist (Antag) AM-251 (0.1 μM) on ascending contraction (left) and descending relaxation (right) components of the peristaltic reflex. ○, Control responses; •, responses following addition of AM-251 to peripheral orad motor compartment for ascending contraction and to peripheral caudad motor compartment for descending relaxation; ▴, responses following addition of AM251 to the central sensory compartment. Separate colons and animals were used for measuring response after addition to central sensory compartment, for addition to orad peripheral motor compartment (ascending contraction), and for addition to caudad peripheral motor compartment (descending relaxation). Values are means ± SE of 3–6 experiments. *P < 0.05.