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Biomedical subjects

M Bourin

Publications and source records attributed to M Bourin.

At least 127 records · Page 7Linked to original sources
PubMed1991

Clonidine as a sensitizing agent in the forced swimming test for revealing antidepressant activity.

The forced swimming test (FST) in mice has failed to predict antidepressant activity for drugs having beta adrenoreceptor agonist activity and for serotonin uptake inhibitors. We investigated the potential for clonidine to render the FST sensitive to antidepressants by using a behaviorally inactive dose of this agent (0.1 mg/kg). All antidepressants studied (tricyclics, 5-HT uptake inhibitors, iprindole, mianserin, viloxazine, trazodone) showed either activity at lower doses or activity at previously inactive doses. The effect appeared specific because it did not appear with drugs other than antidepressants (diazepam, chlorpromazine, sulpiride, atropine), except for amphetamine and apomorphine which have a strong effect on the dopaminergic system. The use of behaviorally subactive doses of clonidine may thus provide an important means of increasing the sensitivity of the forced swimming test.

Animals↗
PubMed1991

Dose ranging study of the effects of cholecystokinin in healthy volunteers.

The authors determined whether response to cholecystokinin-tetrapeptide (CCK-4) was dose-dependent. Healthy volunteers (n = 36) received double-blind injections of either 9 micrograms, 25 micrograms, or 50 micrograms of CCK-4 and placebo in a randomized sequence of injection. Significant dose-related differences were found for the number of symptoms, sum intensity of symptoms and the time until onset of symptoms, but not for the duration of symptoms. The incidence of panic attacks with CCK-4 was 11%, 17% and 47% for the 9 micrograms, 25 micrograms and 50 micrograms dose, respectively. None of the controls panicked with placebo injections. These results support the notion of a dose-dependent effect of CCK-4-induced panic symptoms. Implications of these findings in the neurobiology of panic attacks are discussed.

Adult↗
PubMed1990

Is it possible to predict the activity of a new antidepressant in animals with simple psychopharmacological tests?

Behavioural tests for predicting antidepressant activity in the animal provide a closer approximation than other tests of states of depression in man but are often long and costly to perform (except the behavioural despair test). The tests proposed here presuppose a pharmacological interaction (except the Porsolt test) but are simple enough to allow screening: included are antagonism of reserpine hypothermia, ptosis and akinesia; antagonism of effects induced by oxotremorine; antagonism of high-dose apomorphine; and potentiation of yohimbine toxicity. In combination with the study of motor activity in the mouse, these tests allow assessment of the specificity of antidepressant activity by establishing a ratio between the "antidepressant" dose and the "stimulant" or "sedative" dose. It can be predicted that a substance will be antidepressant and sedative or stimulant at the same dose if the ratio is close to 1; if the ratio is less than 1, at antidepressant doses the substance will be very sedative or stimulant according to the case. The specificity of the tests discussed can be debatable. Antagonism of reserpine-induced hypothermia indicates substances with direct or indirect beta-mimetic activity, ptosis antagonism, substances with alpha-adrenergic (not antidepressants) or serotoninergic (possibly antidepressants) activity; and akinesia antagonism, a direct or indirect dopaminergic activity (sometimes found in antidepressants) with psychostimulant activity. The oxotremorine test is related to the anticholinergic activity of substances, except in the case of hypothermia antagonism. The high-dose apomorphine test seems to be specific for substances inhibiting norepinephrine reuptake. The yohimbine test is simple to carry out, relatively inexpensive and does not fail to screen any molecule known to be effective to-date. The behavioural despair test is a good complement for screening except for drugs having a beta-agonist activity, it appears that this test is dependent on functional relationships between alpha 2 and serotonergic systems.

Animals↗
PubMed1989

Comparative pharmacokinetic study of conventional and sustained-release viloxazine in normal volunteers.

Animal and human studies have indicated that viloxazine hydrochloride, an antidepressant drug with a half-life of 3-4 h in most subjects at low dosage, is rapidly and almost completely absorbed after oral administration. A sustained-release form might be useful to decrease the frequency of administration. In our study, the pharmacokinetics of sustained-release form containing 300 mg viloxazine were compared with 300 mg conventional viloxazine in 11 normal volunteers (6 women, 5 men). Wide interindividual variations were observed with respect to plasma levels, but there was no significant statistical correlation between weight and blood concentration (conventional form: Cmax = 3,599 +/- 579 ng/ml, tmax = 86 +/- 26 min; sustained-release form: Cmax = 1,917 +/- 922 ng/ml, tmax = 215 +/- 77 min). Twelve hours after administration, plasma levels ranged between 540 and 1,600 ng/ml for the conventional form and between 660 and 2,120 ng/ml for the sustained-release form. Despite the great interindividual variation this new viloxazine form appears to be of interest for one daily administration.

Administration, Oral↗
PubMed1989

Effects of single oral doses of bromazepam, buspirone and clobazam on performance tasks and memory.

Three anxiolytic drugs (bromazepam 3 mg, buspirone 10 mg, and clobazam 10 mg p.o.) were evaluated for their effects on memory, psychomotor performance and subjective response in a double-blind, placebo-controlled, crossover study in 20 healthy volunteers. At each session, measurements were made before and 2 and 6 h after drug administration. The psychometric tests used were the images test, digit/symbol substitution test (DSST), choice reaction time (CRT), and critical fusion frequency (CFF). Free recall after 30 s in the 2-hour session was altered for all 3 drugs as compared to placebo (p less than 0.01), but in the 6-hour session only bromazepam showed a significant difference (p less than 0.05). The number of symbols reproduced by subjects during DSST was significantly decreased by bromazepam and buspirone as compared to placebo (p less than 0.05), whereas clobazam showed no differences with placebo. Analysis of variance for all four treatments (the 3 drugs and the placebo) showed no differences at recognition time or for motor response in CRT, except between bromazepam and clobazam after 6 h (p less than 0.05). None of the drugs altered performance during CFF (except bromazepam), and clobazam actually improved performance. All the drugs studied disturbed acquisition phenomena or restitution of memory; however, only bromazepam and buspirone significantly modified performance during DSST and disturbed the recognition and processing of sensory data.

Administration, Oral↗
PubMed1988

Additive effects of clonidine and antidepressant drugs in the mouse forced-swimming test.

In the mouse forced-swimming model, dose-dependent reversal of immobility was induced by the alpha-agonist clonidine given IP 30 min before testing. In addition, three preferential inhibitors of 5-HT uptake (citalopram, indalpine and fluvoxamine) had similar activity in the dose range 8-16 mg/kg as did the 5-HT1 agonist 8-OH-DPAT (1-4 mg/kg). Pretreatment with alpha-methyl-paratyrosine (100 mg/kg) did not prevent clonidine (1 mg/kg) action, suggesting that there was mediation by alpha post-junctional receptors. The effect of clonidine was unaltered by prazosin (2 mg/kg) and reversed by yohimbine (4 mg/kg) and 5-MeODMT (1 mg/kg), whereas it was potentiated by reserpine (2.5 mg/kg), methysergide (2 mg/kg) and ketanserin (8 mg/kg). Moreover, an ineffective dose of clonidine (0.06 mg/kg at 45 min pre-testing) made active subthreshold doses of various antidepressants (given at 30 min pre-testing): imipramine (4 mg/kg), amitriptyline (1 mg/kg), maprotiline (8 mg/kg), citalopram (2 mg/kg), indalpine, fluvoxamine and mianserin (4 mg/kg), viloxazine (2 mg/kg). Similar interactions were found with iprindole and nialamide (32 mg/kg), which were inactive alone up to 64 mg/kg, and 8-OH-DPAT (0.5 mg/kg) but not with major and minor tranquillizers. It is suggested that one effect of antidepressants might be the triggering of different relationships between alpha-2 and 5-HT mechanisms.

Animals↗
PubMed1988

Influence of alpha stimulants and beta blockers on yohimbine toxicity.

1. Potentiation of yohimbine-induced sublethality has been largely used to predict antidepressant action. 2. Several products were tested in order to understand the mechanism of this toxicity better: an alpha-1 central stimulant (adrafinil); an alpha-2 central stimulant (clonidine); and 4 beta-blockers (propranolol, atenolol, penbutolol and metoprolol). 3. It was found that atenolol and adrafinil could not antagonize toxicity, whereas clonidine and the other 3 beta-blockers could. 4. It is suggested that a central beta-origin toxicity exists since only beta-blockers which cross the blood-brain barrier are capable of antagonizing this activity. 5. The fact that clonidine also antagonized this toxicity may be explained by the beta-antagonist action of this substance at the high doses used.

Adrenergic alpha-Agonists↗
PubMed1988

Quantitative analysis of serum methohexital by GLC using capillary column and nitrogen-selective detection.

A gas chromatographic method for routine quantitation of methohexital in plasma samples is reported. One-step extraction in organic phase, the use of a fused silica capillary column, and nitrogen-selective detection permit simple, precise, and sensitive determination of methohexital in plasma. A linear relationship is described between peak height ratio and methohexital concentrations ranging from 0.125 to 50.0 micrograms/ml (r = 0.998). The sensitivity limit of the assay was 6 ng/ml in plasma. No interfering peak was observed with numerous other drugs. The procedure was successfully applied to the determination of pharmacokinetic parameters of methohexital after IV administration or continuous infusion in a child and an adult.

Chemical Phenomena↗
PubMed1988

Is iprindole an indirect betamimetic drug?

Iprindole, an active antidepressant in clinical use, has no effect on norepinephrine reuptake and does not bind to receptors of the noradrenergic system. Iprindole weakly antagonizes reserpine hypothermia and potentiates yohimbine toxicity. This effect is antagonized by propranolol but not by atenolol or metoprolol. In an acute dose, iprindole potentiates the effect of maprotiline on yohimbine toxicity. Beta 2-adrenergic agonists and antagonists specifically modify the effect of iprindole on spontaneous motility. These results indicate that iprindole has an indirect beta 2-mimetic effect.

Adrenergic beta-Agonists↗
PubMed1988

A 2-amino-2-oxazoline derivative as an antidepressant in mice.

2-Amino-2-oxazolines are heterocyclic compounds with interesting pharmacological properties. Several derivatives of this chemical series were studied in psychopharmacological tests. One derivative 4,5-dihydro-5-[methyl(4-phenyl-1-piperazinyl)]-2-oxazolamine (COR 32-24), had an antidepressant profile. Its structure can be compared to trazodone in its phenylpiperazine group and to toloxatone in its oxazoline group. This molecule antagonized reserpine-induced hypothermia and ptosis, oxotremorine-induced hypothermia and high-dose apomorphine-induced hypothermia. It also potentiated yohimbine-induced sublethality and decreased the immobility of forced swimming. It had no monoamine oxidase inhibitory activity. These results suggest a profile close to that of viloxazine and to that of a classic antidepressant.

5-Hydroxytryptophan↗
PubMed1988

Effects of administration route on pharmacokinetics of aspirin in the rabbit.

The absorption of aspirin used in the form of lysine acetylsalicylate was studied in the rabbit. Each animal received the drug by three routes: intravenous, gastric and duodenal. Plasma concentrations of acetylsalicylic acid (ASA) and salicylic acid (SA) were compared. ASA plasma concentrations obtained after gastric or duodenal administration were low compared to those after intravenous injection. Concentrations were 2 to 5 times higher after gastric than duodenal administration. SA plasma concentrations were lower at the beginning of the experiment for gastric than for duodenal administration; after 90 min the concentrations were similar. A better absorption of aspirin (as lysine acetylsalicylate) after administration occurred in the stomach than in the duodenum, but the amount of ASA which reached the central compartment was quite poor.

Animals↗
PubMed1987

Rapid gas-chromatographic assay of bupivacaine in plasma.

A method for estimating bupivacaine concentration in human plasma by capillary gas-chromatography using solid injection and nitrogen-specific detection is described. Etidocaine, another anilidetype local anesthetic was used as internal standard and added to the sample before single-step extraction with diethylether. This method demonstrates high sensitivity (6 ng/ml plasma) and combines selectivity, rapidity, and simplicity. Results of this procedure correlate well with those obtained by an HPLC method.

Bupivacaine↗
PubMed1987

Viloxazine as a betamimetic antidepressant drug.

A comparison was made between the effects of maprotiline, the sole action of which is to inhibit the reuptake of noradrenaline, of salbutamol and of viloxazine on hypothermia induced by reserpine, oxotremorine or apomorphine. The dose/effect curves in the three tests showed a similarity in profile between viloxazine and salbutamol, whereas no resemblance was evident between these two drugs and maprotiline. These facts suggest that viloxazine which has a weak effect on noradrenaline reuptake acts probably as antidepressant by betamimetic activity.

Albuterol↗
PubMed1987

Effects of kainic acid on hypothermia induced by reserpine, oxotremorine and apomorphine in mice.

Antagonists of the norepinephrine reuptake and beta-adrenoreceptor agonists are potent, at once, on the three following tests: antagonism of hypothermia induced by reserpine, oxotremorine and apomorphine. 2-Carboxy-4-isopropenyl-3-pyrrolidine-acetic acid (kainic acid), which is a powerful stimulant of the neurons and a destroyer of the dopaminergic neurons, has been used in these tests to show if it is possible to antagonize hypothermia induced by different substances. The results obtained show that kainic acid is potent on these three tests, thus providing evidence that it is a stimulant of norepinephrine neurons as well as serotoninergic neurons, even if it is peripherically injected.

Animals↗
PubMed1987

A barbital derivative as an atypical antidepressant drug in mice.

An isopropyl derivative of barbital (5,5-diethyl-2-(isopropyloxy)pyrimidine-4,6-dione, O2IB) was administered intraperitoneally 30 min before tests in mice. Former experimental investigations have shown that O2IB has an antidepressant psychopharmacological spectrum. It increases toxicity of yohimbine in mice at 175 mg/kg, antagonises from 50 mg/kg on hypothermia induced by a high dose of apomorphine and is active on the behavioural despair test at 125 mg/kg. These effects are those observed with classical antidepressants. Since phenytoin has an antidepressant profile in mice, carbamazepine is active on manic-depressive illness and beta-mimetic drugs are antidepressants, the question presents itself whether isopropylation or anticonvulsive activity is more important for the antidepressant psychopharmacological spectrum, or whether both are of equal importance.

Animals↗