Figure 6.

Concentration–response curves for the inhibition of the electrical field stimulation-evoked contractions of the rat (A and C) and guinea-pig (B and D) myenteric plexus-longitudinal muscle (MPLM) by anandamide, arachidonylethanolamide (AEA) (A and B) and WIN 55,212-2 [(R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)-pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate] (C and D), constructed in the presence of ethanol, AA-5HT (arachidonyl-5-hydroxytryptamine), PMSF (phenylmethylsulphonyl fluoride) or URB-597 (3′-carbamoyl-biphenyl-3-yl-cyclohexylcarbamate). The rat and guinea-pig MPLM were subjected to single electrical pulses of 0.5 ms duration, 110% supramaximal voltage at a frequency of 0.05 and 0.1 Hz respectively. Each curve was fitted by non-linear regression analysis. Each symbol represents the mean value of inhibition of the contractions expressed as a percentage reduction of the amplitude of the contraction measured immediately before the addition of any drug to the organ bath. Vertical lines indicate SEM, n= 6 for each curve. AA-5HT, PMSF or URB-597 or ethanol was added 15 min before the first addition of AEA and WIN 55,212-2.