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A J Farré

Publications and source records attributed to A J Farré.

At least 19 recordsLinked to original sources

Decrease of adenylyl cyclase activity and expression by a sigma1 receptor ligand and putative atypical antipsychotic.

We examined whether changes in the adenylyl cyclase system could be induced by the administration of the sigma1 receptor ligand and putative atypical antipsychotic 4-[4-fluorophenyl]-1,2,3,6-tetrahydro-1-[4-[1,-2,4-triazol-1-il]butyl]pyridine citrate) (E-5842). Repeated (21 days) but not acute (2 h) treatment with E-5842 induced a significant decrease in adenylyl cyclase type I immunoreactivity and adenylyl cyclase activity in rat frontal cortex membranes, with less or no effect in other brain regions such as the hippocampus or the striatum. Changes in immunoreactivity were not observed in other adenylyl cyclases (type V/VI). The reported changes, observed only after a chronic treatment, could be related to the mechanism of action of sigma receptor ligands in general or to that of E-5842 in particular and should be taken into account, given the long duration of treatment in psychiatric patients.

Adenylyl Cyclases↗

Fibroblast growth factor-2 is selectively modulated in the rat brain by E-5842, a preferential sigma-1 receptor ligand and putative atypical antipsychotic.

Fibroblast growth factor-2 (FGF-2) is a member of a large family of trophic factors whose expression is regulated under several conditions in different areas of the brain. The goal of our experiments was to determine whether the administration of 4-(4-fluorophenyl)-1,2,3,6-tetrahydro-1-[4-(1,2,4-triazol-1-il)butyl] pyridine citrate (E-5842), a sigma-1 receptor ligand and putative atypical antipsychotic, could regulate the expression of FGF-2. After chronic treatment with E-5842 (21 days, and the animals killed 24 h after the last administration), an up-regulation was observed of the expression of FGF-2 mRNA in the prefrontal cortex and the striatum, and a down-regulation of the expression of FGF-2 mRNA in the hypothalamus of the rat brain. Acute treatment with E-5842 (one single administration and animals killed 6 h later) up-regulated FGF-2 expression in the prefrontal cortex, the striatum, the hypothalamus and the hippocampus in a dose-dependent manner. The acute up-regulation was transient and disappeared 24 h after E-5842 administration. The induction of FGF-2 in the striatum after repeated administration has been described for clozapine, but our data concerning regulation in the prefrontal cortex suggest that this effect is unique to E-5852 among other antipsychotics. Given the neuroprotective activity of FGF-2, the data presented here might be relevant to the deficit in cognition and other symptoms that appear in schizophrenia.

Animals↗

Changes in phosphoinositide signalling activity and levels of the alpha subunit of G(q/11) protein in rat brain induced by E-5842, a sigma(1) receptor ligand and potential atypical antipsychotic.

Changes in the phosphoinositide (PPI) signal transduction system induced by E-5842, a new sigma(1) (sigma(1)) receptor ligand and potential atypical antipsychotic, were studied in the rat frontal cortex, hippocampus and striatum. Acute treatment with E-5842 increased phospholipase C (PLC) activity in the striatum and the hippocampus. Chronic treatment with E-5842 induced an increase in the activity of PLC in the frontal cortex and the striatum. Similar up-regulation of the activity of the enzyme was also observed in rat frontal cortex membranes in presence of GTPgammaS. After chronic treatment with E-5842, it was also observed a significant increase of the immunoreactivity levels of G(q/11)alpha in the frontal cortex. Our results suggest that part of the antipsychotic effects of E-5842 could be related to the regulation of the PPI signal transduction pathway, especially after a prolonged treatment.

Animals↗

Up-regulation of sigma(1) receptor mRNA in rat brain by a putative atypical antipsychotic and sigma receptor ligand.

Sigma(1) (sigma(1)) receptor mRNA expression was studied in the prefrontal cortex, striatum, hippocampus and cerebellum of rat brain by northern blot and in situ hybridization. The effects of a chronic treatment with antipsychotic drugs (haloperidol and clozapine), and with E-5842, a sigma(1) receptor ligand and putative atypical antipsychotic on sigma(1) receptor expression were examined. A significant increase in the levels of sigma(1) receptor mRNA in the prefrontal cortex and striatum after E-5842 administration was observed, while no apparent changes were seen with either haloperidol or clozapine. Our results suggest a long-term adaptation of the sigma(1) receptor at the level of mRNA expression in specific areas of the brain as a response to a sustained treatment with E-5842.

Animals↗

Regulation of ionotropic glutamate receptor subunits in different rat brain areas by a preferential sigma(1) receptor ligand and potential atypical antipsychotic.

The effect of chronic administration of the putative atypical antipsychotic E-5842, a preferential sigma(1) receptor ligand, on ionotropic glutamate receptor subunit levels of mRNA and protein, was studied. The repeated administration of E-5842 differentially regulated levels of the NMDA-2A and of GluR2 subunits in a regionally specific way. Levels of immunoreactivity for the NMDA-2A subunit were up-regulated in the medial prefrontal cortex, the frontoparietal cortex, the cingulate cortex, and in the dorsal striatum, while they were down-regulated in the nucleus accumbens. Levels of the GluR2 subunit of the AMPA receptor were up-regulated in the medial prefrontal cortex and the nucleus accumbens and down-regulation was observed in the dorso-lateral striatum. Regulation of the levels of mRNA for the different subunits was also observed in some cases. The results show that E-5842, through a mechanism still unknown, is able to modify levels of several glutamate receptor subunits and these changes could be related to its antipsychotic activity in pre-clinical tests.

Animals↗

Pharmacology of cizolirtine: a new analgesic agent.

Cizolirtine citrate (E-4018) is a new analgesic agent with antinociceptive activity against phenylquinone (ED50 33.7 mg/kg) and acetic acid (ED50 24.4 mg/kg) in mice, against acetic acid in rats (ED50 21.3 mg/kg) and in the plantar test (ED50 26.8 mg/kg). It demonstrated antinociceptive activity in the tail-pinch and tail-flick tests (ED50s of 68.0 and 46.0 mg/kg, respectively), in both phases of the formalin test (ED50 13.8 and 2.31 mg/kg), and in the capsaicin test (ED50 7.14 mg/kg). Cizolirtine does not inhibit prostaglandin biosynthesis, it is not a ligand for opioid receptors, it does not have antiinflammatory or ulcerogenic activity, it has some antipyretic activity and shows no affinity for alpha 2-adrenergic receptors, but its analgesic effect was modified by idazoxan and by desipramine. Recent studies have shown that the analgesic effect of cizolirtine could be related, at least partially, to an inhibition of spinal substance P release.

Analgesics↗

The effect of E-5842, a sigma receptor ligand and potential atypical antipsychotic, on Fos expression in rat forebrain.

We examined the ability of E-5842 (4-(4-fluorophenil)-1,2,3,6- tetrahydro-1-[4-(1,2,4-triazol-1-il)butyl] pyridine citrate), a sigma receptor ligand, to increase Fos protein expression in regions of rat forebrain. An acute administration of E-5842 increased levels of Fos in the medial prefrontal cortex and the nucleus accumbens, without affecting the levels of the protein in the striatum, an effect very similar to that of clozapine. Our results suggest that E-5842 may be an atypical antipsychotic with low propensity to produce extrapyramidal side-effects.

Animals↗

General pharmacological profile and effects of E-4716, a novel histamine receptor blocker, on the central nervous system.

The general pharmacological profile and effects of E-4716 on the CNS have been investigated in comparison with other histamine receptor blockers. In in vitro studies with isolated organs and in binding studies on numerous receptors, E-4716 had no activity even at high concentrations, except for the selective blockade of H1 receptors. No activity was observed in pharmacological trials in vivo, such as the Irwin test or analgesia induced by phenylbenzoquinone or electroshock, suggesting a depressant activity on the CNS. In tests potentiating hypnosis induced by barbiturates, benzodiazepines and ethanol in mice, E-4716 always showed milder potentiating effects than the other reference drugs. In monkeys, no sedating effects were observed at 200 mg/kg, p.o. These results suggest that E-4716 exhibits good clinical efficacy without any secondary effects.

Animals↗

Antiasthma activity of the novel antihistamine E-4716 in guinea pigs in vivo.

The effects of E-4716, a novel antihistamine compound, on histamine-induced bronchoconstriction, platelet activating factor (PAF)- or antigen-induced airway hyperreactivity, eosinophil infiltration, and airway microvascular leakage were compared with those of reference drugs in guinea pigs in vivo. E-4716 (300 microg/kg, i.v. or i.p.) suppressed histamine-induced bronchoconstriction in nonsensitized anesthetized guinea pigs and effectively inhibited acetylcholine-induced bronchial hyperreactivity in nonsensitized animals 24 h after PAF aerosol exposure. E-4716 also attenuated antigen-induced acute respiratory distress and suppressed histamine-induced airways hyperreactivity in conscious sensitized animals 24 h after antigen exposure, but did not affect the increased number of eosinophils in the bronchoalveolar lavage fluid. E-4716 300 microg/kg, i.v. or 1 mg/ml by inhalation (60 breaths) inhibited both PAF- and antigen-induced airway microvascular leakage. This in vivo profile of activity, comprising antihistamine, antihyperreactivity and antiexudative effects, suggests that E-4716 is of potential therapeutic value as an antiasthma and/or antiallergic drug.

Analysis of Variance↗

Effects of a novel 5-HT1A receptor agonist, E4424, on gastric adherent mucus levels following restraint stress in rats.

Several novel arylpiperazine serotonin 1A receptor agonists, developed as anxiolytics, have antisecretory and gastroprotective effects in rats. E4424 (2-¿4-[4-(4-chloropyrazol-1-yl)butyl]-1-piperazinyl ¿pyrimidine; Lesopitron dihydrochloride), has potent anti-gastric secretory and antiulcer effects. Preliminary data indicated an enhancing effect of E4424 on gastric mucus that may underlie its gastroprotective actions. We therefore tested the effects of acute and chronic administration of E4424 and of a reference 5-HT1A receptor agonist, 8-OHDPAT [8-hydroxy-2-(di-n-propylamino)tetralin], on gastric mucus levels in rats subjected to cold-restraint stress, a procedure associated with depletion of gastric mucus and the development of mucosal injury. Acute oral administration of E4424 increased adherent mucus levels by 12%, 11%, and 13%, relative to controls. Chronic E4424 significantly increased gastric mucus relative to controls (69% increase). Acute oral treatment with 8-OHDPAT did not affect gastric mucus level. Acute intraperitoneal 8-OHDPAT slightly increased mucus levels. Chronic twice per day 8-OHDPAT did not affect mucus levels; however, chronic once per day treatment with 8-OHDPAT significantly elevated gastric mucus levels at the highest doses used. For E4424, there is a strong correlation between reduction of gastric mucosal injury and increase in gastric mucus level, suggesting that the action of E4424 on glandular mucus levels is an important mechanism underlying its gastroprotective effects.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Some novel 5-hydroxytryptamine1A (5-HT1A) receptor agonists reduce gastric acid and pepsin secretion, reduce experimental gastric mucosal injury and enhance gastric mucus in rats.

The present studies examined the actions of a series of novel arylpiperazine 5-hydroxytryptamine1A (5-HT1A) agonists, developed originally for anxiolytic efficacy, in several models of gastric secretion and experimental gastric mucosal injury. These models included conscious gastric acid secretion, pylorus ligation (gastric acid and pepsin secretion), stress-induced gastric mucosal injury, ethanol-induced gastric mucosal damage and gastric adherent mucus levels. 2-(4-[4-(4-Nitropyrazol-1- yl)butyl]-1-piperazinyl)pyrimidine (E4414) and 2-(4-[4-(4-chloropyrazol-1-yl)butyl]-1-piperazinyl)pyrimidine dihydrochloride (E4424) significantly inhibited gastric acid secretion in conscious as well as in pylorus-ligated rats. Both compounds also significantly reduced pepsin secretion in pylorus-ligated animals. E4414 and E4424 significantly reduced both stress-induced and ethanol-induced gastric mucosal injury, and both compounds significantly maintained gastric adherent mucus levels in rats subjected to stress. The antisecretory and gastroprotective actions of E4414 and E4424 were of significantly greater magnitude than those of the reference 5-HT1A agonists, buspirone and 8-hydroxy-2-(di-n- propylamino)tetralin. These results suggest that some novel 5-HT1A agonists exert gastroprotection not only through reduction of aggressive elements in the gut (acid and pepsin secretion) but also through enhancement of defensive gastrointestinal factors such as adherent mucus.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Interactions of lesopitron (E-4424) with central 5-HT1A receptors: in vitro and in vivo studies in the rat.

Previous studies have shown that the 5-HT1A receptor ligand, lesopitron (E-4424, 2-[4-[4-(4-chloro-1-pyrazolyl)butyl]-1-piperazinyl]pyrimidine), exerts potent anxiolytic-like effects in rodents and monkeys (Costall et al., 1992, J. Pharmacol. Exp. Ther. 262, 90). In an attempt to determine whether these effects are really mediated through the interaction of lesopitron with central 5-HT1A receptors, we investigated the agonistic and/or antagonistic nature of this interaction under in vitro and in vivo conditions in the rat. In vitro binding and autoradiographic studies with [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT) and [3H]lesopitron as radioligands confirmed that lesopitron binds to 5-HT1A receptors in the rat brain with a relatively high affinity (pKi = 7.35). As expected of a full agonist at postsynaptic 5-HT1A receptors, lesopitron (IC50 = 125 nM) inhibited forskolin-stimulated adenylate cyclase activity in rat hippocampal membranes to the same extent as 5-HT, and this effect was preventable by potent 5-HT1A receptor antagonists such as (-)-tertatolol, (-)-propranolol and N-tert-butyl-3,4-(2-methoxyphenyl)piperazin-1-yl-2-phenyl- propanamide ((+)-WAY 100135). As previously shown for agonists acting at the somato-dendritic 5-HT1A autoreceptors in the dorsal raphe nucleus, lesopitron inhibited the firing of serotoninergic neurons both in vitro (in brainstem slices, IC50 = 120 nM) and in vivo (in chloral hydrate-anaesthetized rats, ID50 = 35 micrograms/kg i.v.), and this effect was preventable by (-)-tertatolol. Interestingly, the inhibition of the discharge due to lesopitron lasted for only a few minutes both in vitro and in vivo whereas the anxiolytic-like properties of this drug lasted for hours after a single injection in mice (Costall et al., 1992). In addition, the doses required for the stimulation of pre- and postsynaptic 5-HT1A receptors were markedly higher than those producing significant anxiolytic-like effects in rodents (Costall et al., 1992). It is therefore unlikely that the anxiolytic-like properties of lesopitron involve its stimulatory action at central 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Isolated gastric mucosa: an early approach to the study of the mechanism of action of gastric antisecretory agents.

The results of five different experiments carried out on isolated gastric mucosa were evaluated. These were: 1) Effects of antisecretory agents on (H+) and (K+) in a histamine-stimulated (4 x 10(-5)M) preparation. 2) Effects on (H+) in a preparation stimulated by dibutyryl cyclic adenosine monophosphate (dbcAMP) (6 x 10(-4)M). 3) Reversal by antipyrine (3 x 10(-2)M) of the antacid effect of antisecretory agents in a histamine-stimulated (4 x 10(-5)M) preparation. 4) Effects on the antacid activity of antisecretory agents of a pretreatment with 2-mercaptoethanol (2-ME) (2 x 10(-2)M) in a histamine-stimulated (4 x 10(-5] preparation. 5) Reversal by intraluminal increase of (K+) (up to 144.3 mM) of the antacid effect of antisecretory agents in a histamine-stimulated (4 x 10(-5)M) preparation. The technique and its application to a series of known antisecretory agents--cimetidine, ranitidine, timoprazole and omeprazole--and to other substances with antisecretory activity such as sodium thiocyanate, verapamil, trimipramine and imipramine, is described. In order to illustrate the activity of the aforementioned substances in the more classic tests of antisecretory activity, an in vivo test of inhibition of gastric secretion in pylorus-ligated rats and the in vitro tests of H2-receptor blocking activity (isolated guinea-pig atrium), anticholinergic activity (isolated guinea-pig ileum) and carbonic anhydrase (canine blood) were included. The results show that substances with different mechanisms of action behave differently in the five experiments in isolated gastric mucosa described, and these may thus be considered useful for the study of the mechanism of action of gastric antisecretory agents.

Animals↗

Maximum tolerated temperature in the rat tail: a broadly sensitive test of analgesic activity.

The methods most frequently employed for the study of analgesic activity of opiates are those based on thermal stimuli (hot-plate, tail-flick, TWR). These tests, however, are only sensitive for opiates which are pure agonists. In this work, we propose a modification of the TWR method capable of detecting analgesic activity in both agonist and agonist-antagonist opiates. In addition, non-opiate analgesics also show activity in this test. The ED50 (mg/kg, i.p.) of the substances studied, administered 30 min before commencement of the test, were as follows: buprenorphine: 0.02; methadone: 0.08; morphine: 1.9; pentazocine: 4.5; d-propoxyphene: 5.5; codeine: 7.6; pethidine: 9.2; zomepirac: 20.1; suprofen: 138.0; acetylsalicylic acid: 453.4. There was a statistically significant linear correlation between the results obtained by the proposed method (MTT) and those of some of the most frequently used methods for the study of analgesic agents (writhing induced by phenylbenzoquinone, acetic acid, acetylcholine bromide, hot-plate test and rat tail withdrawal test). The simplicity of the method makes it suitable for use in the battery of screening tests for analgesic activity of both narcotic and non-narcotic substances.

Acetates↗

Pharmacological profile of droxicam.

In Studies of anti-inflammatory activity, droxicam has shown itself to be as active as piroxicam and much more active than phenylbutazone, isoxicam and suprofen, both in acute studies such as carrageenin oedema, nystatin oedema and ultraviolet erythema, and in longer-term tests such as that of the cotton pellet. In the studies of anti-arthritic activity, which require long-term treatment, droxicam was as effective as piroxicam, both on primary and on secondary lesions. The study of analgaesic activity, conducted by means of the tests of protective activity against writhing induced by phenylbenzoquinone and acetylcholine bromide in the mouse and by acetic acid in the rat, droxicam activity was superior to that of acetylsalicylic acid, dipyrone, isoxicam and phenylbutazone. Droxicam also showed antipyretic activity in the rat, greater than that of acetylsalicylic acid, dipyrone and 4-aminoantipyrine, in the brewer's yeast and Salmonella typhi tests. Droxicam also acts as an ex vivo platelet aggregation inhibitor in the dog. In the study of inhibition of peritoneal capillary permeability in the mouse, droxicam was considerably more potent than isoxicam or phenylbutazone. Studies of general pharmacology have demonstrated that droxicam, at high doses, has no cardiovascular or respiratory effects, and that neither does it modify behaviour in rats and mice, determined by the Irwin test. Gastrointestinal tolerance of droxicam has been compared with that of piroxicam, and it has been found that droxicam is far better tolerated. The study of induction of gastrointestinal lesions in the rat demonstrated that the gastrolesive potential of droxicam is 10 times inferior to that of piroxicam.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Inhibition of aconitine-induced mortality in the conscious rat: a screening test for antiarrhythmic drugs.

A test for inhibition of mortality induced by intravenous injection of aconitine in rats is proposed as a particularly valid method, owing to its simplicity and degree of specificity, for inclusion among the preliminary screening tests for antiarrhythmic activity. LD50 (63.5 micrograms/kg, i.v.) and LD99 (118.9 micrograms/kg, i.v.) values of aconitine were determined. The dose employed for screening was 100 micrograms/kg i.v., which in control animals produced a death rate of 97.7% (293 deaths/300 treated animals). The protection produced by various drugs belonging to different groups of antiarrhythmics was studied. ED50s, expressed in mg/kg i.p., were as follows: Class I antiarrhythmics: flecainide, 5.5; E-4017, 30.0; lorcainide, 30.9; quinidine, 41.1; diphenylhydantoin, 42.3; lidocaine, 48.5; ajmaline: 53.9; procainamide, 61.3. Class II antiarrhythmics: pindolol 22.8; propranolol, 24.9; oxprenolol, 38.0; labetalol, 60.7; atenolol, 100.0; metoprolol, approximately 160; acebutalol, greater than 160; timolol, greater than 160. Class III antiarrhythmics: amiodarone, greater than 160. Class IV antiarrhythmics: verapamil, diltiazem and nifedipine were inactive up to 40 mg/kg. The test would appear to be selective for membrane-stabilizing agents (class I) and beta-blockers (class II), but in view of the magnitudes of activity found, it should be used in combination with other antiarrhythmic tests.

Aconitine↗

Pharmacological properties of besulpamide, a new diuretic, in rats and dogs.

Besulpamide, a newly synthesized compound, has demonstrated significant diuretic activity in rats and dogs, similar to that of chlorthalidone, clopamide and xipamide. Antihypertensive activity of besulpamide is similar to that of hydrochlorothiazide and was demonstrated in rat one-kidney desoxycorticosterone acetate (DOCA)-salt hypertension. In addition, besulpamide, like hydrochlorothiazide, potentiated the antihypertensive activity of captopril in spontaneously hypertensive rats (SHR). Doses of besulpamide exceeding those normally required for pharmacological activity did not evoke adverse reactions in rats and mice.

Animals↗

Pharmacological properties of droxicam, a new non-steroidal anti-inflammatory agent.

Droxicam showed high antiinflammatory activity in carrageenin-induced edema in rat. At doses of 0.25 and 0.5 mg/kg, droxicam was as active as piroxicam and more active than phenylbutazone given at 2.5 and 5 mg/kg. Against nystatin-induced edema, droxicam (ED50, p.o., 5, 6, 7, 8 h: 7.5, 12.9, 4.8, 8.4 mg/kg) was 4-11 times more active than phenylbutazone and more than 12 times more active than isoxicam. In cotton pellet-induced granuloma in rats, title compound was as active as suprofen. In U.V. light-induced erythema in guinea pigs, droxicam (ED50, p.o., 1, 2, 3, 4 h: 0.51, 0.94, 1.56, 4.88 mg/kg) was 5-9 times more active than phenylbutazone. At doses of 0.1, 0.33 and 1.0 mg/kg/day, droxicam, similar to piroxicam, showed good antiarthritic activity in rats injected with Mycobacterium butyricum against primary and secondary lesions. Droxicam demonstrated strong analgesic activity in protecting against writhings: induced by phenylbenzoquinone in mice: ED50: droxicam = 5.3, phenylbutazone = 61.5, acetylsalicylic acid = 90.7, dipyrone = 83.6, isoxicam = 88.3 mg/kg, p.o.; induced by acetylcholine bromide in mice: ED50: droxicam = 1.1, phenylbutazone = 32.1, acetylsalicylic acid = 32.2, isoxicam = 32.7 mg/kg, p.o.; induced by acetic acid in rat: ED50: droxicam = 0.94, acetylsalicylic acid = 8.72, isoxicam = 4.70 mg/kg, p.o. Antipyretic activity of title compound was demonstrated in rats with pyresis induced by brewer's yeast, being 4-13 times more active than dipyrone. In pyresis induced by Salmonella typhi, droxicam was more active than acetylsalicylic acid and 4-aminoantipyrine at all times and doses. In a study of protection against diarrhea induced by castor oil in rats, droxicam and piroxicam showed equal activity (ED50 = 0.081 and 0.079 mg/kg, p.o., respectively) and were 3.9 and 15.6 times more active than isoxicam and phenylbutazone, respectively. Droxicam significantly inhibited peritoneal capillary permeability in mice at a dose of 5 mg/kg, p.o., while isoxicam and phenylbutazone required 100 and 200 mg/kg, p.o., respectively. Droxicam did not exhibit uricosuric activity in rats. It did not show cardiovascular or respiratory effects in anesthetized cats, nor modify their response to administration of acetylcholine, norepinephrine and histamine. In the Irwin's test, droxicam did not alter rat behavior (80 mg/kg, i.p.) nor that of mice (160 mg/kg, p.o.). Induction of gastrointestinal injuries in rats by droxicam was 10 times less than by piroxicam (UD50: droxicam, 57 mg/kg, p.o.; piroxicam, 5.6 mg/kg, p.o.). The potentiation of gastric injuries induced by stress through cold in rats was also studied.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗