1
|
Nakagawa T, Doi A, Ohno K, Yokoyama N, Tsujimoto H. Clinical features and prognosis of canine megaesophagus in Japan. J Vet Med Sci 2019; 81:348-352. [PMID: 30626762 PMCID: PMC6451904 DOI: 10.1292/jvms.18-0493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Megaesophagus (ME) is a common esophageal disease in dogs and the prognosis is generally poor, especially with aspiration pneumonia (AP). We retrospectively investigated the clinical
features and prognosis of canine ME in Japan. Twenty-eight dogs were included in this study, with the Miniature Dachshund breed being significantly overrepresented (odds ratio: 4.33). Most
cases (21 of 28) were diagnosed as idiopathic ME and Myasthenia gravis was the most common cause of secondary ME. The overall median survival time (MST) was not reached and the 3-month
survival rate was 85.7%. Ten dogs were diagnosed with AP, at least once during the study period, and the MST of ME dogs with AP was 114 days. The survival time overall and even with AP, was
notably more prolonged compared to the previous studies. We hypothesized that treatment for canine ME could prolong the survival time, even in those with both ME and AP.
Collapse
Affiliation(s)
- Taisuke Nakagawa
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Akihiro Doi
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Koichi Ohno
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Nozomu Yokoyama
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hajime Tsujimoto
- Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| |
Collapse
|
2
|
Quintavalla F, Menozzi A, Pozzoli C, Poli E, Donati P, Wyler DK, Serventi P, Bertini S. Sildenafil improves clinical signs and radiographic features in dogs with congenital idiopathic megaoesophagus: a randomised controlled trial. Vet Rec 2017; 180:404. [PMID: 28188161 DOI: 10.1136/vr.103832] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2017] [Indexed: 11/04/2022]
Abstract
We evaluated the efficacy of oral sildenafil citrate in dogs with congenital idiopathic megaoesophagus (CIM). Twenty-one puppies were randomly assigned to two groups (treatment and control). The dogs were given sildenafil oral suspension 1 mg/kg every 12 hours for 14 days or placebo in a masked fashion. Clinical signs (frequency of regurgitation and weight gain) and oesophagrams (relative oesophageal diameter, ROD) were evaluated in order to assess the efficacy of drug treatment, by examiners who were unaware of the study protocol. In addition, a set of in vitro experiments on isolated samples of canine lower oesophageal sphincter (LOS) was performed, and the effects of increasing concentrations of sildenafil on basal tone and electrically-stimulated motility were assessed. Sildenafil administration significantly reduced the number of regurgitation episodes (0.88±1.40 v 2.65±1.56, P<0.0001) and significantly increased weight gain in the treated dogs compared to controls (79.76±28.30 per cent v 53.40±19.30 per cent, P=0.034). ROD values, at the end of the treatment period, were significantly decreased in the sildenafil group, compared to pre-treatment values (0.97±0.19 v 0.24±0.14, P<0.0001), in contrast to control subjects (0.98±0.17 v 1.10±0.25, P=0.480). In accordance with the in vivo findings, sildenafil dose-dependently reduced basal tone and increased electrically-induced relaxation of dog LOS samples. These results suggest that sildenafil citrate helps ameliorate clinical and radiographic signs in dogs with CIM by reducing LOS tone, and could represent a novel therapeutic tool for the treatment of this disease.
Collapse
Affiliation(s)
- F Quintavalla
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - A Menozzi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - C Pozzoli
- Department of Neuroscience, University of Parma, Parma, Italy
| | - E Poli
- Department of Neuroscience, University of Parma, Parma, Italy
| | | | - D K Wyler
- The Animal Medical Hospital and Whitestone Veterinary Care, New York, NY, USA
| | - P Serventi
- Department of Veterinary Science, University of Parma, Parma, Italy
| | - S Bertini
- Department of Veterinary Science, University of Parma, Parma, Italy
| |
Collapse
|
3
|
Shiina T, Naitou K, Nakamori H, Suzuki Y, Horii K, Sano Y, Shimaoka H, Shimizu Y. Serotonin-induced contractile responses of esophageal smooth muscle in the house musk shrew (Suncus murinus). Neurogastroenterol Motil 2016; 28:1641-1648. [PMID: 27194102 DOI: 10.1111/nmo.12863] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/22/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Serotonin (5-hydroxytryptamine, 5-HT) is a regulatory factor in motility of the gastrointestinal tract including the esophagus. Although we proposed that vagal cholinergic and mast cell-derived non-cholinergic components including serotonin coordinately shorten the esophagus, the precise mechanism of serotonin-induced contractions in the suncus esophagus is still unclear. Therefore, the aims of this study were to determine characteristics of contractile responses induced by serotonin and to identify 5-HT receptor subtypes responsible for regulating motility in the suncus esophagus. METHODS An isolated segment of the suncus esophagus was placed in an organ bath, and longitudinal or circular mechanical responses were recorded using a force transducer. KEY RESULTS Serotonin evoked contractile responses of the suncus esophagus in the longitudinal direction but not in the circular direction. Tetrodotoxin did not affect the serotonin-induced contractions. Pretreatment with a non-selective 5-HT receptor antagonist or double application of 5-HT1 and 5-HT2 receptor antagonists blocked the serotonin-induced contractions. 5-HT1 and 5-HT2 receptor agonists, but not a 5-HT3 receptor agonist, evoked contractile responses in the suncus esophagus. CONCLUSION & INFERENCES The findings suggest that serotonin induces contractile responses of the longitudinal smooth muscle in the muscularis mucosae of the suncus esophagus that are mediated via 5-HT1 and 5-HT2 receptors on muscle cells. The serotonin-induced contractions might contribute to esophageal peristalsis and emetic response.
Collapse
Affiliation(s)
- T Shiina
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.
| | - K Naitou
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - H Nakamori
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Y Suzuki
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - K Horii
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Y Sano
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - H Shimaoka
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Y Shimizu
- Laboratory of Physiology, Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| |
Collapse
|
4
|
Li HF, Liu JF, Zhang K, Feng Y. Expression of serotonin receptors in human lower esophageal sphincter. Exp Ther Med 2014; 9:49-54. [PMID: 25452775 PMCID: PMC4247306 DOI: 10.3892/etm.2014.2050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 10/08/2014] [Indexed: 12/13/2022] Open
Abstract
Serotonin (5-HT) is a neurotransmitter and vasoactive amine that is involved in the regulation of a large number of physiological functions. The wide variety of 5-HT-mediated functions is due to the existence of different classes of serotonergic receptors in the mammalian gastrointestinal tract and nervous system. The aim of this study was to explore the expression of multiple types of 5-HT receptor (5-HT1AR, 5-HT2AR, 5-HT3AR, 5-HT4R, 5-HT5AR, 5-HT6R and 5-HT7R) in sling and clasp fibers from the human lower esophageal sphincter (LES). Muscle strips of sling and clasp fibers from the LES were obtained from patients undergoing esophagogastrectomy, and circular muscle strips from the esophagus and stomach were used as controls. Reverse transcription-polymerase chain reaction (RT-PCR), quantitative PCR and western blotting were used to investigate the expression of the various 5-HT receptor types. Messenger RNA for all seven 5-HT receptor types was identified in the sling and clasp fibers of the LES. At the mRNA level, the expression levels were highest for 5-HT3AR and 5-HT4R, and lowest for 5-HT5AR, 5-HT6R and 5-HT7R. At the protein level, the expression levels were highest for 5-HT3AR and 5-HT4R, followed by 5-HT1AR and 5-HT2AR; 5-HT7R was also detected at a low level. The expression of 5-HT5AR and 5-HT6R proteins was not confirmed. The results indicate that a variety of 5-HT receptor types can be detected in the human LES and probably contribute to LES function.
Collapse
Affiliation(s)
- He-Fei Li
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Jun-Feng Liu
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Ke Zhang
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Yong Feng
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| |
Collapse
|
5
|
Hempfling C, Neuhuber WL, Wörl J. Serotonin-immunoreactive neurons and mast cells in the mouse esophagus suggest involvement of serotonin in both motility control and neuroimmune interactions. Neurogastroenterol Motil 2012; 24:e67-78. [PMID: 22029710 DOI: 10.1111/j.1365-2982.2011.01797.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Serotonin is a major transmitter in the gastrointestinal tract, but little is known about the serotonergic system in the esophagus. METHODS The aim of this study was to use multilabel immunofluorescence to characterize serotonin-positive nerve cell bodies and fibers and their relationship with other neuronal and non-neuronal elements in the mouse esophagus. Antibodies against serotonin, vesicular acetylcholine transporter (VAChT), choline acetyltransferase (ChAT), protein gene product 9.5 (PGP 9.5), and α-bungarotoxin (α-BT), were used. KEY RESULTS Serotonin-containing perikarya represented ∼10% of all PGP 9.5-positive myenteric neurons. Serotonin-positive varicose nerve fibers were found in the lamina muscularis mucosae and present on ∼13% of α-BT-labeled motor endplates in addition to VAChT-immunoreactive motor terminals. As ChAT-positive neurons of the compact formation of the nucleus ambiguus were negative for serotonin, serotonin-positive varicosities on motor endplates are presumed to be of enteric origin. On the other hand, cholinergic ambiguus neurons were densely supplied with serotonin-positive varicosities. The tela submucosa and tunica adventitia contained large numbers of serotonin-positive mast cells, a few of which were in close association with serotonin-positive nerve fibers. CONCLUSIONS & INFERENCES The mouse esophagus is endowed with a rich serotonin-positive intrinsic innervation, including enteric co-innervation of striated muscles. Serotonin may modulate vagal motor innervation of esophageal-striated muscles not only at the central level via projections of the raphe nuclei to the nucleus ambiguus but also at the peripheral level via enteric co-innervation. In addition, mast cells represent a non-neuronal source of serotonin, being involved in neuroimmune processes.
Collapse
Affiliation(s)
- C Hempfling
- Institute of Anatomy, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | | |
Collapse
|
6
|
Vickery RG, Mai N, Kaufman E, Beattie DT, Pulido-Rios T, O'Keefe M, Humphrey PPA, Smith JAM. A comparison of the pharmacological properties of guinea-pig and human recombinant 5-HT4 receptors. Br J Pharmacol 2007; 150:782-91. [PMID: 17293885 PMCID: PMC2013860 DOI: 10.1038/sj.bjp.0707154] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 11/22/2006] [Accepted: 12/11/2006] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE 5-HT(4) receptor agonists are used therapeutically to treat disorders of reduced gastrointestinal motility. Since such compounds are evaluated in guinea-pigs, we cloned, expressed and pharmacologically characterized the guinea-pig 5-HT(4) and human 5-HT(4(b)) splice variant, which share 95% homology. The functional properties of guinea-pig 5-HT(4(b)) receptors were compared with native receptors in guinea-pig colon. EXPERIMENTAL APPROACH Membrane radioligand binding and whole cell cAMP accumulation assays were used to determine the affinities, potencies and intrinsic activities (IA). Contraction of the guinea-pig distal colon longitudinal muscle myenteric plexus preparation (LMMP) was monitored to evaluate functional activity. KEY RESULTS pK(i) values for guinea-pig and human recombinant receptors, and guinea-pig striatum 5-HT(4) receptors, were in agreement, as were the potency and IA values for guinea-pig and human 5-HT(4) receptors expressed at a similar density ( approximately 0.2 pmol mg(-1) protein). Tegaserod was a potent (pEC(50)=8.4 and 8.7, respectively), full agonist at both guinea-pig and human 5-HT(4) receptors. In contrast, in the LMMP preparation, tegaserod was a potent, partial agonist (pEC(50)=8.2; IA=66%). CONCLUSIONS AND IMPLICATIONS Close agreement between the pharmacological properties of guinea-pig and human 5-HT(4) receptors support the use of guinea-pig model systems for the identification of 5-HT(4) receptor therapeutics. However, the mechanisms underlying the different agonist properties of tegaserod in recombinant and isolated tissue preparations, and the extent to which these impact the clinical efficacy of tegaserod as a prokinetic agent, remain to be determined.
Collapse
Affiliation(s)
- R G Vickery
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| | - N Mai
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| | - E Kaufman
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| | - D T Beattie
- Department of Pharmacology, Theravance Inc. South San Francisco, CA, USA
| | - T Pulido-Rios
- Department of Pharmacology, Theravance Inc. South San Francisco, CA, USA
| | - M O'Keefe
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| | - P P A Humphrey
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| | - J A M Smith
- Department of Molecular and Cell Biology, Theravance Inc. South San Francisco, CA, USA
| |
Collapse
|
7
|
Armstrong SR, McCullough JL, Beattie DT. Measurement of 5-HT4 receptor-mediated esophageal responses by digital sonomicrometry in the anesthetized rat. J Pharmacol Toxicol Methods 2005; 53:198-205. [PMID: 16168678 DOI: 10.1016/j.vascn.2005.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Accepted: 08/14/2005] [Indexed: 01/07/2023]
Abstract
INTRODUCTION In vitro studies have demonstrated a 5-HT4 receptor-mediated relaxation of the pre-contracted rat esophagus. However, it is unclear whether 5-HT4 receptor agonists affect resting esophageal tone in vivo. The activity of 5-HT and several well-established 5-HT4 receptor agonists (tegaserod, BIMU-8, cisapride, renzapride, and mosapride) was investigated in a novel in vivo model designed to measure esophageal relaxation using the technique of digital sonomicrometry. METHODS Miniature piezo-electric crystals were implanted externally in a longitudinal orientation on the distal esophagus of isoflurane-anesthetized, adult male Sprague-Dawley rats. Measurement of the time for transmission of ultrasonic pulses between the implanted crystals provided a continuous recording of inter-crystal distance and hence esophageal muscle length. RESULTS Following cumulative intravenous administration, 5-HT (1-100 microg/kg), tegaserod (1-1000 microg/kg), BIMU-8 (3-3000 microg/kg), renzapride (10-3000 microg/kg), cisapride (30-3000 microg/kg), and mosapride (30-10,000 microg/kg) produced a dose-dependent increase in esophageal inter-crystal distance. The mean ED50 values for tegaserod, BIMU-8, renzapride, cisapride, and mosapride were 11, 49, 51, 141, and 1825 microg/kg, respectively. Pre-treatment with the selective 5-HT4 receptor antagonist, piboserod (SB-207266; 1 mg/kg subcutaneously) significantly attenuated the effects of intravenous tegaserod (1-1000 microg/kg). Following cumulative intraduodenal administration (0.03-10 mg/kg), tegaserod and mosapride exhibited a dose-dependent increase in esophageal inter-crystal distance. The doses associated with a 10% increase in muscle length from the resting level were 2.6 and>10 mg/kg for tegaserod and mosapride, respectively. DISCUSSION In conclusion, dose-dependent, 5-HT4 receptor agonist-mediated increases in longitudinal muscle length in the rat esophagus were observed in vivo using the technique of digital sonomicrometry. This in vivo model of esophageal activity may prove useful in evaluating the activity of novel 5-HT4 receptor agonists.
Collapse
Affiliation(s)
- Scott R Armstrong
- Pharmacology Laboratories, Theravance, Inc., 901 Gateway Blvd., South San Francisco, CA 94080, USA.
| | | | | |
Collapse
|
8
|
Washabau RJ. Gastrointestinal motility disorders and gastrointestinal prokinetic therapy. Vet Clin North Am Small Anim Pract 2003; 33:1007-28, vi. [PMID: 14552159 DOI: 10.1016/s0195-5616(03)00076-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gastrointestinal motility disorders represent a diagnostic and therapeutic challenge. Disorders of gastrointestinal motility may result in accelerated transit, delayed transit, impaired relaxation, or inappropriate relaxation. The delayed transit disorders are the most important motility disorders of companion animals and may involve the esophagus (hypomotility and megaesophagus), stomach (delayed gastric emptying), small intestine (postoperative ileus and intestinal pseudo-obstruction), or colon (constipation and megacolon).
Collapse
Affiliation(s)
- Robert J Washabau
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010, USA.
| |
Collapse
|
9
|
Prins NH, Akkermans LM, Lefebvre RA, Schuurkes JA. 5-HT(4) receptors on cholinergic nerves involved in contractility of canine and human large intestine longitudinal muscle. Br J Pharmacol 2000; 131:927-32. [PMID: 11053213 PMCID: PMC1572403 DOI: 10.1038/sj.bjp.0703615] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
5-HT(4) receptors mediate circular muscle relaxation in both human and canine large intestine, but this phenomenon alone can not explain the improvement in colonic motility induced by selective 5-HT(4) receptor agonists in vivo. We set out to characterize 5-HT(4) receptor-mediated effects in longitudinal muscle strips of canine and human large intestine. Electrical field stimulation (EFS) was applied providing submaximal isotonic contractions. L-NOARG (0.1 mM) was continuously present in the organ bath to preclude nitric oxide-induced relaxation to EFS. The selective 5-HT(4) receptor agonist prucalopride (0.3 microM) enhanced EFS-evoked contractions, that were antagonized in both preparations by the selective 5-HT(4) receptor antagonist GR 113808 (0.1 microM). The prucalopride-induced increase was present in canine ascending and descending colon, but absent in rectum. Regional differences in response to prucalopride were not observed in human ascending and sigmoid colon and rectum. Incubation with atropine (1 microM) or tetrodotoxin (0.3 microM) inhibited EFS-induced contractions, which were then unaffected by prucalopride (0.3 microM) in both tissues. In the presence of methysergide (3 microM; both tissues) and granisetron (0.3 microM; only human tissues), 5-HT (0.3 microM) enhanced EFS-induced contractions, an effect that was antagonized by GR 113808 (0.1 microM). In the presence of atropine or tetrodotoxin, EFS-induced contractions were inhibited, leaving 5-HT (0.3 microM) ineffective in both preparations. This study demonstrates for the first time that in human and canine large intestine, 5-HT(4) receptors are located on cholinergic neurones, presumably mediating facilitating release of acetylcholine, resulting in enhanced longitudinal muscle contractility. This study and previous circular muscle strip studies suggest that 5-HT(4) receptor agonism facilitates colonic propulsion via a coordinated combination of inhibition of circumferential resistance and enhancement of longitudinal muscle contractility.
Collapse
Affiliation(s)
- N H Prins
- Department of Gastrointestinal Pharmacology, Janssen Research Foundation, Beerse, Belgium.
| | | | | | | |
Collapse
|
10
|
Schaus JM, Thompson DC, Bloomquist WE, Susemichel AD, Calligaro DO, Cohen ML. Synthesis and structure-activity relationships of potent and orally active 5-HT4 receptor antagonists: indazole and benzimidazolone derivatives. J Med Chem 1998; 41:1943-55. [PMID: 9599243 DOI: 10.1021/jm970857f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A series of indole-3-carboxamides, indazole-3-carboxamides, and benzimidazolone-3-carboxamides was synthesized and evaluated for antagonist affinity at the 5-HT4 receptor in the rat esophagus. The endo-3-tropanamine derivatives in the indazole and benzimidazolone series possessed greater 5-HT4 receptor affinity than the corresponding indole analogues. 5-HT4 receptor antagonist affinity was further increased by alkylation at N-1 of the aromatic heterocycle. In a series of 1-isopropylindazole-3-carboxamides, replacement of the bicyclic tropane ring system with the monocyclic piperidine ring system or an acyclic aminoalkylene chain led to potent 5-HT4 receptor antagonists. In particular, those systems in which the basic amine was substituted with groups capable of forming hydrogen bonds showed increased 5-HT4 receptor antagonist activity. While some of these compounds displayed high affinity for other neurotransmitter receptors (in particular, 5-HT3, alpha1, and 5-HT2A receptors), as the conformational flexibility of the amine moiety increased, the selectivity for the 5-HT4 receptor also increased. From this series of compounds, we identified LY353433 (1-(1-methylethyl)-N-[2-[4-[(tricyclo[3.3.1.1(3, 7)]dec-1-ylcarbonyl)amino]-1-piperidinyl]ethyl]-1H-indazole-3- carboxamide) as a potent and selective 5-HT4 receptor antagonist with clinically suitable pharmacodynamics.
Collapse
MESH Headings
- Adamantane/administration & dosage
- Adamantane/analogs & derivatives
- Adamantane/chemical synthesis
- Adamantane/chemistry
- Adamantane/pharmacology
- Administration, Oral
- Adrenergic alpha-Antagonists/chemical synthesis
- Adrenergic alpha-Antagonists/chemistry
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Aorta/drug effects
- Aorta/physiology
- Brain/drug effects
- Brain/metabolism
- Drug Evaluation, Preclinical
- Esophagus/drug effects
- Esophagus/physiology
- Guinea Pigs
- Ileum/drug effects
- Ileum/physiology
- In Vitro Techniques
- Indazoles/administration & dosage
- Indazoles/chemical synthesis
- Indazoles/chemistry
- Indazoles/pharmacology
- Muscle Contraction/drug effects
- Muscle, Smooth/drug effects
- Muscle, Smooth/physiology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Rats
- Receptor, Serotonin, 5-HT2A
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Serotonin/drug effects
- Receptors, Serotonin, 5-HT3
- Receptors, Serotonin, 5-HT4
- Serotonin Antagonists/administration & dosage
- Serotonin Antagonists/chemical synthesis
- Serotonin Antagonists/chemistry
- Serotonin Antagonists/pharmacology
- Structure-Activity Relationship
Collapse
Affiliation(s)
- J M Schaus
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA
| | | | | | | | | | | |
Collapse
|
11
|
Hansen MB, Skadhauge E. Signal transduction pathways for serotonin as an intestinal secretagogue. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART A, PHYSIOLOGY 1997; 118:283-90. [PMID: 9366057 DOI: 10.1016/s0300-9629(97)00085-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This review presents a signal transduction pathways for serotonin (5-hydroxytryptamine, 5-HT) as an intestinal secretagogue and some recently published related findings. 5-HT is a secretagogue in the small and large intestine of all studied species including pig and man. 5-HT mediates intestinal secretion through activation of at least the epithelial 5-HT2, and neuronal 5-HT3, and 5-HT4 receptors in the submucosal plexus, including a reflex arc. 5-HT activates both a cholinergic and a non-cholinergic pathway in its secretory response. Intracellular mediators include at least eicosanoids (prostaglandin E2), calcium, phosphoinositols (1,4,5-inositol trisphosphate) and maybe nitric oxide and cyclic nucleotides. Pig small intestine appears to be an appropriate model for the human small intestine with respect to the signal transduction pathways for 5-HT as an intestinal secretagogue. Species and segmental differences in the signal transduction pathways for 5-HT as an intestinal secretagogues are discussed together with related news on 5-HT receptors, 5-HT antagonists in clinical use, the enteric nervous system, and intracellular mediators.
Collapse
Affiliation(s)
- M B Hansen
- Department of Anatomy and Physiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark
| | | |
Collapse
|