# Tachykinin NK1 receptors are involved in proteinase-activated receptor-2-mediated visceral hyperalgesia in rats

Bruno Guiard, Nicolas Cenac, Rafael Garcia Villar, Anne-Marie Coelho, Jean Fioramonti, Lionel Bueno

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## ► To cite this version:

Bruno Guiard, Nicolas Cenac, Rafael Garcia Villar, Anne-Marie Coelho, Jean Fioramonti, et al. Tachykinin NK1 receptors are involved in proteinase-activated receptor-2-mediated visceral hyperalgesia in rats. 18. International Symposium on Neurogastroenterology and Motility, Sep 2001, Madison, United States. 2001, Neurogastroenterol Mot 13 (4 Suppl.). [hal-01600688](https://hal.science/hal-01600688)

HAL Id: hal-01600688

https://hal.science/hal-01600688

Submitted on 4 Jun 2020

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Abstracts of papers accepted for presentation
at the XVIII International Symposium on
Neurogastroenterology and Motility

16–20 September, Madison, WI, USA
## The Australian possum sphincter of Oddi acts as a pump and/or a resistor, depending on common bile duct pressure

M. B. GRIVELL, C. M. WOODS, A. G. CRAIG, J. TOOLI & G. T. P. SACCONE

Department of General and Digestive Surgery, Flinders Univers, Flinders Medical Centre, Bedford Park, South Australia, Australia

The sphincter of Oddi (SO) is believed to regulate transsphincteric flow by acting as a pump or a resistor, depending on the species studied. The possum SO acts as a resistor at physiological common bile duct (CBD) pressure. However the CBD pressure, which is the pressure imposed on the SO, can vary under physiological and pathophysiological conditions. Aim. To determine if SO motor activity, which regulates transsphincteric flow, is altered by varying the CBD pressure. Methods. An in vitro preparation consisting of the CBD, SO and a small region of the duodenum (n = 7) was mounted in an organ bath containing oxygenated Krebs solution at 37 °C. An external reservoir was used to alter the CBD hydrostatic pressure [0-14 mmHg]. Pressure in the CBD, and contractions of the proximal, mid and distal SO were recorded simultaneously using a low flow multilumen manometry catheter. SO outflow was collected via a small cup over the papilla and measured gravimetrically. Results. At CBD pressures <3.5 mmHg, the SO displays peristaltic-like pumping of duration 2-4 s and consists of the following sequence of sphincteric motor events. 1. The proximal SO circular muscle contracts (enclosing a small volume of fluid in the SO) while simultaneously the closed distal SO begins to relax, but does not open. 2. The SO longitudinal muscle (assessed visually) and then the mid-SO circular muscle contract, increasing fluid pressure within the SO. 3. When the pressure in the mid-SO exceeds that of the relaxing distal SO, 7-18 microlitres of fluid are pumped into the duodenum. 4. The distal SO then contracts to stop flow (and prevent reflux from the duodenum) whilst the proximal SO relaxes to allow refilling of the SO from the CBD. At CBD pressures of 3.5-4 mmHg, in addition to SO pumping, passive SO outflow occurs between pumping events as the CBD pressure exceeds the distal SO pressure. At CBD pressures > 6 mmHg, the proximal SO contractions are weak and flow through the SO is entirely passive occurring between distal SO contractions which act as a resistor to flow. SO outflow is a linear function of CBD pressure between 3.5 and 14 mmHg. Conclusion. The CBD pressure is a major determinant of the SO motor pattern.

## Tachykinin NK1 receptors are involved in proteinase-activated RECEPTOR-2-mediated visceral hyperalgesia in rats

B. GUIARD, N. CENAC, R. GARCIA-VILLAR, A. M. COELHO, J. FIORAMONTI & L. BUENO

INRA, Neuro-Gastroenterology & Nutrition Unit, TOULOUSE, France

Proteinase-activated receptors-2 (PAR-2) are expressed in primary afferent neurones and demonstrated to be involved in somatic pain transmission. Recently it has been shown that intracolonic infusion to rats of the PAR-2 activating peptide SLIGRL, increased visceral sensitivity as shown by a delayed and long-lasting hyperalgesia to rectal distension (RD). The aim of this study was to determine the involvement of substance P (SP) and calcitonin gene-related peptide (CGRP), which are coreleased by primary afferent neurones, in PAR-2-induced visceral hyperalgesia. Methods. Six groups (n = 6-8) of male Wistar rats (250-300 g) were surgically equipped with an intracolonic (IC) catheter for the infusion of SLIGRL, and electrodes to record abdominal muscle contractions used as an indicator of pain. RD was performed with increasing volumes (0-1.2 mL) applied by steps of 0.4 mL, each step lasting 5 min. Groups 1 and 2 were infused IC, respectively, with both SLIGRL [active peptide] or saline (control) and the NK1 receptor antagonist SR140333 (1 mg kg⁻¹, i.p): in a first series of experiments SR140333 was administered before SLIGRL or saline; in a second series of experiments, performed three days later, SR140333 was administered 10 h after SLIGRL or saline. Groups 3 and 4 were similarly infused IC with both SLIGRL or saline and the CGRP receptor antagonist human CGRP 8-37 (100 µg kg⁻¹ i.v.), before and 10 h after SLIGRL or saline. Groups 5 and 6 were treated with either SP (10 µg kg⁻¹, i.p.) plus SR140333 (1 mg kg⁻¹, i.p.; 30 min later) or CGRP (10 µg kg⁻¹, i.v.) plus hCGRP 8-37 (100 µg kg⁻¹, i.v.; 30 min later) in order to assess the efficiency of these antagonists on SP- and CGRP-induced hyperalgesia, respectively. Values (mean ± SEM) are the

number of abdominal contractions for the 5-min episode with the highest volume of distension (1.2 mL) and were compared using Student's paired t-test for each group of rats. **Results.** As expected SLIGRL (group 1) but not saline (group 2) given intracolonically induced delayed (10 h) visceral hyperalgesia to RD (45.0 ± 4.1 contractions vs. 33.3 ± 3.0 in basal conditions, i.e. a 36% increase; *P* < 0.05). In group 1, SR140333 inhibited SLIGRL-induced hyperalgesia when administered before SLIGRL (31.2 ± 4.5; *P* < 0.05) but had no effect when given after SLIGRL (48.0 ± 4.8; *P* > 0.05). At this dose, SR140333 suppressed SP-induced hyperalgesia (group 5). Similarly, SLIGRL (group 3) but not saline (group 4) increased the number of abdominal contractions by 47% in response to the 1.2 mL volume of rectal distension at 10 h postinfusion. In group 3, hCGRP 8-37 (100 µg kg⁻¹) did not significantly affect SLIGRL-induced hyperalgesia when administered either before or after SLIGRL. However at this dose hCGRP 8-37 suppressed CGRP (50 µg kg⁻¹)-induced hyperalgesia (group 6). **Conclusion.** The present study shows that NK1 receptor antagonist prevents SLIGRL-induced visceral hyperalgesia and suggests that tachykinins and most probably SP, but not CGRP, are involved in the peripheral sensitization of primary afferent neurones induced by PAR-2 activation.

## Light- and electron-microscopic study of nerves and ICC in the mouse colon after the acute phase of experimental denervation

M. HANANI, O. LEDDER, M. G. VANNUCCHI & M. S. FAUSSONE-PELLEGRINI

Hadassah University Hospital, Jerusalem 91240, Israel, and University of Florence, 150139, Florence, Italy.

The detergent benzalkonium chloride (BAC) has been used previously to induce denervation in the rat small and large intestines. These studies provided interesting information on nerve degeneration and also showed abnormalities in interstitial cells of Cajal (ICC). We used BAC in the mouse colon to investigate whether, after the acute phase of experimental denervation, there were re-innervation and ICC recovery in the damaged area. To observe cellular changes we used histochemical methods at the light microscopic level (PGP9.5, S-100, NADPH-d, c-Kit) and electron microscopy. Tissues were examined 2, 7, 14 and 30 days after BAC treatment. We found that two days after BAC the treated area was almost completely devoid of nerve elements and of ICC at the myenteric plexus (ICC-MP). Seven days after BAC there was a small degree of nerve fibre growth into the denervated region. At 14 days there was a considerable growth of nerve fibres and these new fibres were either arranged in parallel with the muscle cells or formed a meshwork at myenteric plexus region, as in the normal colon. At least some of the newly grown nerve processes were found to originate from myenteric neurones located in the undamaged area and were always ensheathed by glial cells. At 30 days nerve fibres were present in most of the denervated area and scattered neurones occasionally accompanied these fibres in the myenteric region. ICC did not reappear in the denervated area and at 30 days the density of peg and socket junctions among muscle cells was considerably increased. We conclude that the BAC method is useful for investigating neuronal plasticity and re-innervation processes. In contrast to nerves, ICC did not migrate into the damaged area, and they also did not seem to regenerate in this region. This lack of ICC plasticity might have important clinical implications. Supported by BSF (98-00185).

## The intrinsic regulation of small intestinal motility is mediated by both myenteric and submucous neurones

J. HENS, D. ADRIAENSEN, D. W. SCHEUERMANN & J-P. TIMMERMANS

Laboratory of Cell Biology and Histology, University of Antwerp, Belgium

Based mainly on experimental data obtained from small laboratory animals, for a long time intestinal motility was thought to be exclusively regulated by myenteric neurones as far as the intrinsic neuronal component is concerned. More recently, several investigators could demonstrate that, particularly in large mammals, including humans, also submucous neurones are participating in the intrinsic innervation of the outer circular smooth muscle layer (CM) of the intestine.¹⁻³ The present study, using a combination of *in vitro* supravital tracing and immunohistochemistry provides evidence that in the pig small intestine, besides the myenteric plexus (MP; 86%) also the inner (ISP; 4%)