Volume 116, Issue 1, Pages 108-117 (January 1999) Functional significance of a newly discovered neuropeptide, orphanin FQ, in rat gastrointestinal motility  Ali Yazdani, Toku Takahashi, Didier Bagnol, Stanley J. Watson, Chung Owyang  Gastroenterology  Volume 116, Issue 1, Pages 108-117 (January 1999) DOI: 10.1016/S0016-5085(99)70234-9 Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 1 Effects of 10−7 mol/L OFQ on contractility of the longitudinal muscle in rat gastrointestinal tract. Significant contractions in response to OFQ were mainly seen in the colon. Similarly, OFQ also caused significant contractions in rat colonic circular muscle (data not shown). Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 2 Effects of OFQ (10−9 to 10−6 mol/L) on the contractile activity of longitudinal muscle strips obtained from the rat proximal (○) and distal (2) colon (mean ± SE; n = 4). Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 3 Effects of TTX (10−7 mol/L), L-NAME (10−4 mol/L), apamin (10−6 mol/L), and VIP antagonist (5 × 10−6 mol/L) on OFQ (10−8 mol/L)-induced contractions in longitudinal muscle from rat proximal colon. Increased baseline contractions after exposure to OFQ were represented by • and shown on the left. On the right, contraction of muscle strips after preincubation with various antagonists, followed by treatment with OFQ. Spontaneous contractions in the longitudinal muscle layer were enhanced by TTX in the colon, secondary to the removal of inhibitory neural pathways that inhibit the myogenic properties of muscle cells. In the presence of TTX, OFQ failed to evoke additional contractions, whereas carbachol (10−6 mol/L) caused further contractions in the presence of TTX, suggesting that the muscle had not reached maximal contractility. L-NAME and apamin, but not VIP antagonist, caused significant spontaneous contractions in the rat proximal colon. In the presence of L-NAME or apamin, OFQ was able to cause additional contractions. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 4 Effects of (A) 10−7 mol/L TTX, (B) 10−4 mol/L L-NAME, and (C) 10−6 mol/L apamin on OFQ (10−9 to 10−7 mol/L)-induced contractions in longitudinal muscle from the rat proximal colon. In the presence of TTX, OFQ (10−9 to 10−7 mol/L) failed to induce additional contractions. In contrast, OFQ (10−9 to 10−7 mol/L) caused additional contractions in the presence of L-NAME and apamin (mean ± SE; n = 5). Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 5 Effects of veratridine (5 × 10−6 mol/L) on OFQ (10−7 mol/L)-induced contractions in longitudinal muscle from rat proximal colon. Increased baseline contractions after exposure to OFQ were represented by •. Incubation with veratridine (5 × 10−5 mol/L) for 10 minutes completely abolished EFS (65 V, 1 millisecond, 10 Hz)-evoked response without affecting carbachol (10−6 mol/L)-induced contractions. OFQ-induced contractions were completely abolished by the pretreatment with veratridine. These results were reproducible from 3 muscle strips from 3 animals. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 6 OFQ (10−7 mol/L)-induced contractions in longitudinal muscle from rat proximal colon treated with serosal application of (A) saline and (B) BAC. Increased baseline contractions after exposure to OFQ were represented by •. EFS (65 V, 1 millisecond, 10 Hz)-evoked response was completely abolished, but carbachol (10−6 mol/L)-induced contractions remained intact in BAC-treated tissues. OFQ-induced contractions were completely abolished by BAC treatment. Results were reproducible from 3 muscle strips from 3 animals. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 7 Effects of 10−6 mol/L atropine, 10−4 mol/L hexamethonium, 10−5 mol/L naloxone, 3 × 10−5 mol/L methysergide, 10−5 mol/L indomethacin, 10−5 mol/L substance P antagonist, and 5 × 10−6 mol/L VIP antagonist on OFQ (10−8 mol/L)-induced contractions in longitudinal muscle from rat proximal colon. OFQ-induced contractions were not significantly affected by preincubating the muscle strips with these antagonists (mean ± SE; n = 5). Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 8 Effects of Ca2+-free medium on OFQ (10−7 mol/L)-induced contractions in longitudinal muscle in rat proximal colon. OFQ-induced contractions were abolished by Ca2+-free medium. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 9 Effects of OFQ (10−7 mol/L) on EFS (10 Hz, 0.5 millisecond)-evoked muscle contraction in longitudinal muscle obtained from the (A) stomach, (B) ileum, and (C) colon. OFQ (10−7 mol/L) significantly reduced EFS-evoked muscle contraction in ileum and stomach but not in colon. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 10 Effects of OFQ (10−9 to 10−6 mol/L) on EFS (10 Hz, 0.5 millisecond)-evoked muscle contraction in longitudinal muscle from the stomach (•), ileum (▴), and colon (■). OFQ (10−9 to 10−6 mol/L) significantly reduced EFS-evoked muscle contractions in a dose-dependent manner in the ileum and stomach but not in the colon. Maximum effects were observed at OFQ (10−7 mol/L), which reduced EFS-evoked muscle contraction to 41.2% ± 8.5% and 85.2% ± 5.6% of control in the ileum and stomach, respectively. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions

Fig. 11 Immunohistochemical staining of OFQ in the rat colon using whole-mount preparations. Arrows (A and B) indicate the distribution of OFQ-immunoreactive nerve fibers in the myenteric plexus. Some nerve fibers were seen in the circular muscle layer as well (arrows in C). Bars = A, 1000 μm, B and C = 50 μm. Gastroenterology 1999 116, 108-117DOI: (10.1016/S0016-5085(99)70234-9) Copyright © 1999 American Gastroenterological Association Terms and Conditions