Effect of 3M-003, an imidazoquinoline, on phagocyte candidacidal activity directly and via induction of peripheral blood mononuclear cell cytokines.

3M-003, like related imidazoquinoline immunomodulators, interacts with Toll-like receptor-7 (TLR-7) and TLR-8. TLRs are important in the defense against fungal pathogens. The effect of 3M-003 on killing of Candida was evaluated on mouse (BALB/c) effector cell lineages: monocytes, neutrophils, and macrophages.

NK1.1+ cells mediate the antitumor effects of a dual Toll-like receptor 7/8 agonist in the disseminated B16-F10 melanoma model.

Innate immune stimulation with Toll-like receptor (TLR) agonists is a proposed modality for immunotherapy of melanoma. Here, a TLR7/8 agonist, 3M-011, was used effectively as a single systemic agent against disseminated mouse B16-F10 melanoma. The investigation of the mechanism of antitumor action revealed that the agonist had no direct cytotoxic effects on tumor cells tested in vitro.

Pyrrolizidine esters and amides as 5-HT4 receptor agonists and antagonists.

A series of pyrrolizidine esters, amides, and ureas was prepared and tested for 5-HT(4) and 5-HT(3) receptor binding, 5-HT(4) receptor agonism in the rat tunica muscularis mucosae (TMM) assay, and for 5-HT(3) receptor-mediated functional antagonism in the Bezold-Jarisch reflex assay. Several pyrrolizidine derivatives were identified with high affinity for the 5-HT(4) receptor, including benzamide 12a (SC-53116), a potent and selective 5-HT(4) partial agonist that exhibits efficacy in promoting antral contractions and activity in promoting gastric emptying in canine models. Also discovered were 5-HT(4) receptor antagonists, including imidazopyridine amide 12h (SC-53606), which is a potent and selective 5-HT(4) receptor antagonist with a pA(2) value of 8.

Azaadamantane benzamide 5-HT4 agonists: gastrointestinal prokinetic SC-54750.

Azaadamantanone 1 was converted to a series of aminoazaadamantane benzamides 9a-d, which were profiled for serotonin receptor activity. Aminomethylazaadamantane SC-54750 is a potent 5-HT(4) agonist and 5-HT(3) antagonist with in vivo efficacy in gastroparesis models and also inhibits cisplatin-induced emesis.

Cyclic AMP-dependent Cl secretion is regulated by multiple phosphodiesterase subtypes in human colonic epithelial cells.

The role of phosphodiesterase (PDE) isoforms in regulation of transepithelial Cl secretion was investigated using cultured monolayers of T84 cells grown on membrane filters. Identification of the major PDE isoforms present in these cells was determined using ion exchange chromatography in combination with biochemical assays for cGMP and cAMP hydrolysis. The most abundant PDE isoform in these cells was PDE4 accounting for 70-80% of the total cAMP hydrolysis within the cytosolic and membrane fractions from these cells.

Imiquimod-elicited emesis is mediated by the area postrema, but not by direct neuronal activation.

The immunomodulator, imiquimod, has been shown to have antiviral and antitumor properties in animal models. It also has been reported to alter cytokine levels in both animals and humans. However, because imiquimod appeared to be emetic, studies were conducted to determine the degree of sensitivity, and the pathways involved.

Effects of several glucocorticosteroids and PDE4 inhibitors on increases in total lung eosinophil peroxidase (EPO) levels following either systemic or intratracheal administration in sephadex- or ovalbumin-induced inflammatory models.

Representative glucocorticosteroids (GCS) and phosphodiesterase IV (PDE4) inhibitors were compared in several models of pulmonary inflammation ranging in severity. Lung tissue eosinophil peroxidase (EPO) levels rather than bronchoalveolar lavage fluid (BALF) EPO or eosinophil percentages were used to indicate eosinophil recruitment after intratracheal instillation of sephadex beads in rats or nebulized ovalbumin in sensitized guinea pigs. A single oral or intratracheal administration of a GCS was effective against mild and robust sephadex-induced eosinophilia whereas the PDE4 inhibitors evaluated appeared more effective in the milder sephadex models.

Polymeric delivery of the active isomer of misoprostol reduces systemic availability and uterotonic activity.

SC-30249 is the active isomer of misoprostol responsible for its mucosal protective effects against nonsteroidal anti-inflammatory drugs (NSAIDS). Linkage of SC-30249 to a polybutadiene polymer results in a delivery system (SC-55307) that releases the active component only under the acidic conditions of the stomach. This approach could be used to minimize side effects and systemic availability of synthetic prostaglandins.

Serotonin 5-HT3 antagonists fail to affect ethanol self-administration of rats.

Five Long-Evans hooded rats were trained to lever press according to fixed-ratio 5 reinforcement schedules for 0.06 ml dipper deliveries of 8% w/v ethanol during daily (M-F) 0.5-h experimental sessions.

SC-53606, a potent and selective antagonist of 5-hydroxytryptamine4 receptors in isolated rat esophageal tunica muscularis mucosae.

(1-S,8-S)-N-[(hexahydro-1H-pyrrolizin-1-yl)methyl]-6-chloroimi+ ++- dazo[1,2-a]pyridine-8-carboxamide hydrochloride (SC-53606) acts as an antagonist of 5-hydroxytryptamine4 (5-HT4) receptor-mediated relaxation of carbachol-induced contractions in rat esophageal tunica muscular mucosae, but does not possess 5-HT4 agonist activity. SC-53606 demonstrated a pA2 value against 5-HT in this tissue of 7.91 +/- 0.

SC-49518 enhances gastric emptying of solid and liquid meals and stimulates gastrointestinal motility in dogs by a 5-hydroxytryptamine4 receptor mechanism.

SC-49518 (N-[exo-(hexahydro-1H-pyrrolizine-1-yl)methyl]-2-methoxy-4- amino-5-chlorobenzamide HCl), a new benzamide gastrointestinal prokinetic compound, was investigated to determine its ability to stimulate gastrointestinal motility in vivo and whether these actions could be mediated by agonist activity at the putative 5-hydroxytryptamine (5-HT)4 receptor. In conscious fasted dogs with strain gauge transducers and myoelectrodes, SC-49518 disrupted gastric and small intestinal migrating motility complex cycling for more than 3.5 hr.

5-HT4 receptor activation induces relaxation and associated cAMP generation in rat esophagus.

Changes in mechanical events and intracellular levels of cAMP induced by the activation of the 5-HT4 receptor were investigated in the rat esophagus tunica muscularis mucosae preparation. Serotonin (5-HT) and 5 methoxytryptamine (5-MOT; 5-HT4 agonist) caused concentration-related relaxation responses, while 5-carboxamidotryptamine (5-CT; 5-HT1 agonist), 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (DOI; 5-HT2 agonist) and 2-methyl-serotonin (2-methyl-5-HT; 5-HT3 agonist) were less active. The prokinetic agents, cisapride and renzapride also induced concentration-dependent relaxation of rat esophagus which was intermediate to 5-HT and 5-MOT in potency.

Effect of endothelin-1 on guinea pig gallbladder smooth muscle in vitro.

The purpose of this study was to investigate the pharmacological activity of endothelin-1 (ET-1) on guinea pig gallbladder smooth muscle. Guinea pig gallbladder muscle strips were mounted in 10-ml siliconized organ baths containing Krebs' solution. After 1 hr of equilibration, ET-1 was added cumulatively.

Cholecystokinin-mediated ileal electrolyte transport in the guinea pig. Characterization of receptor subtype.

Cholecystokinin (CCK) receptors are currently divided into at least two subtypes: a CCK-A subtype, responsive to the sulfated form of cholecystokinin octapeptide (CCK-8) and selectively antagonized by L-364,718, and a CCK-B subtype, which shares equal affinities for gastrin and CCK-8. In the present study the receptor subtype that mediates guinea pig ileal secretion by evaluating the potencies of CCK- and gastrin-related peptides to evoke increases in transmucosal short-circuit current was characterized. The antagonist potencies of L-365,260 (CCK-B selective) and L-364,718 (CCK-A selective) against CCK-8 were also determined.

Alpha 2-adrenergic model of gastroparesis: validation with renzapride, a stimulator of motility.

Motility-stimulating drugs can increase gastric antral and intestinal contractions but do not usually enhance emptying unless gastroparesis is present. An alpha 2-adrenergic agonist (SC-39585A) was used to inhibit antroduodenal motility and simulate gastroparesis in dogs. SC-39585A caused dose-related inhibition of emptying of solid and liquid meals as well as the antral and duodenal motility responses to the solid meal.

Relationship of serotonin-3 receptor antagonist activity to gastric emptying and motor-stimulating actions of prokinetic drugs in dogs.

Drugs that enhance gastrointestinal motility include the benzamide drugs metoclopramide, cisapride and renzapride (BRL-24924). Because these agents also are serotonin-3 (5-HT3) receptor antagonists, which can promote gastric emptying in some species, the motor-stimulating properties of benzamide agents may be due to this mechanism. Metoclopramide (0.

Monochloramine induces contraction of guinea pig gallbladder via two different pathways.

The purpose of the present investigation was to examine the effect and mechanism of action of the reactive oxygen metabolites monochloramine (NH2Cl), hypochlorous acid (HOCl), and hydrogen peroxide (H2O2) on gallbladder smooth muscle contractility. All oxidants caused concentration-dependent increases in resting tension of gallbladder muscle; the rank order of potencies (half-maximal concentration) was NH2Cl (30 microM) greater than HOCl (70 microM) greater than H2O2 (100 microM). The oxidant concentrations employed are those found to exist in inflamed tissue.

Neutrophil-derived oxidants modify CCK-OP-stimulated guinea pig gallbladder contraction in vitro.

Neutrophil-derived oxidants such as hydrogen peroxide (H2O2), hypochlorous acid (HOCl), and monochloramine (NH2Cl) may contribute to gallbladder inflammation in cholecystitis. We examined the influence of oxidants on the biological activity of different agonists and antagonists of gallbladder smooth muscle function. The concentration-response curves for cholecystokinin-octapeptide (CCK-OP) and carbachol were examined before and after incubation of the tissues with NH2Cl (30 microM).

Differential effects of reactive oxygen metabolites on neurally stimulated and nonstimulated guinea pig ileum.

Large numbers of polymorphonuclear leukocytes which generate reactive oxygen metabolites are found in mucosa and submucosa of the intestinal wall of subjects suffering from inflammatory bowel disease. We have, therefore, examined the relative influences of hydrogen peroxide (H2O2), hypochlorous acid (HOCl) and N-chloramines such as NH2Cl, on the neurally stimulated and nonstimulated guinea pig ileum. In separate experiments the oxidants were tested in the presence and absence of the cyclooxygenase inhibitor piroxicam and the antioxidant glutathione.

Chemistry and structure-activity relationships of C-17 unsaturated 18-cycloalkyl and cycloalkenyl analogues of enisoprost. Identification of a promising new antiulcer prostaglandin.

A series of delta 17 unsaturated cycloalkyl and cycloalkenyl analogues of enisoprost was synthesized to investigate the effects of omega chain unsaturation on gastric antisecretory activity and diarrheogenic side effects. Of these, the 17E, 18-cyclopentenyl analogue 5d displayed potent gastric antisecretory activity in dogs but very weak diarrheogenic properties in rats and is the most selective prostaglandin compound discovered in these laboratories. Structurally, 5d contains both a conjugated diene and tertiary allylic alcohol in the omega chain, and these chemical features impart some interesting oxidative and acid-catalyzed epimerization and allylic rearrangement reactivities, respectively.

Potential antisecretory antidiarrheals. 2. Alpha 2-adrenergic 2-[(aryloxy)alkyl]imidazolines.

Lofexidine, an alpha 2-agonist, has central hypotensive activity and peripheral intestinal antisecretory activity. Analogues were synthesized with increased polarity in an attempt to prevent penetration of the blood-brain barrier. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber with a rabbit ileum preparation.

Gastrointestinal motility stimulating drugs and 5-HT receptors on myenteric neurons.

5-HT3 receptor antagonists may have both antiemetic and gastric and intestinal motility stimulating properties, but they differ in their relative potencies and efficacies for these two activities. Since the 5-HT3 receptor is present on enteric neurons, intracellular recordings of myenteric neuronal transmembrane potential were used to assess the actions of four proposed motility stimulating drugs, metoclopramide, BRL 24924, ICS 205-930 and cisapride. BRL 24924 (10(-6) M), ICS 205-930 (10(-7) M) and cisapride (5 x 10(-6) M) each antagonized the 5-HT3-mediated fast depolarization of myenteric neurons.

18-cycloalkyl analogues of enisoprost.

By use of standard cuprate methodology, a series of 18-cycloalkyl analogues of enisoprost was prepared in an effort to impede omega chain metabolism and prolong duration of gastric antisecretory activity. An initial product of omega chain oxidation, the C-20 hydroxy analogue, was also synthesized for pharmacological comparison. The cyclopropyl, cyclobutyl, and cyclopentyl analogues were approximately one-fourth as potent as enisoprost in inhibiting gastric acid secretion, while the cyclohexyl and cycloheptyl analogues showed very weak activity, and the 20-hydroxy compound was inactive at a dose 100 times the ED50 of enisoprost.

Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase.

A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue.