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Biomedical subjects

A J Puech

Publications and source records attributed to A J Puech.

At least 19 recordsLinked to original sources
PubMed1992

5-HT3 receptor antagonists reverse helpless behaviour in rats.

The effects of the 5-HT3 receptor antagonists, zacopride, ondansetron and ICS 205-930, were investigated in an animal model of depression, the learned helplessness test. Rats previously subjected to a session of 60 inescapable foot-shocks exhibited a deficit of escape performance in three subsequent shuttle-box sessions. The 5-HT3 receptor antagonists administered i.p. twice daily on a chronic schedule (zacopride 0.03-2 mg/kg per day; ondansetron and ICS 205-930: 0.125-2 mg/kg per day) reduced the number of escape failures at low to moderate daily doses. This effect was not observed with the highest dose(s) of zacopride, ondansetron and ICS 205-930 tested. These results indicate that 5-HT3 antagonists may have effects like those of conventional antidepressants in rats.

Analysis of Variance↗
PubMed1992

Comparative investigation of the effect of moclobemide and toloxatone on monoamine oxidase activity and psychometric performance in healthy subjects.

The effects of moclobemide and toloxatone, two reversible monoamine oxidase-A inhibitors, on biochemical parameters that reflect monoamine metabolism and on psychomotor performance parameters were investigated in a study in 12 healthy volunteers. Treatments were given double-blind in a randomized, placebo-controlled cross-over design, with 1 week wash-out between the treatments. Drugs were given thrice daily in the following doses: moclobemide 150-150-150 mg and toloxatone 400-200-400 mg. All assessments were performed on day 8 under standardized conditions. There was no difference with regard to adverse events between moclobemide and toloxatone: both drugs induced a slight decrease in both supine and standing heart rate. Judged on the basis of the area under the curve, the two MAO-inhibitors reduced the plasma levels of DHPG and HVA, with more pronounced effects for moclobemide than for toloxatone. After moclobemide MAO-A inhibition was almost constant over 24 h, whereas the effect of toloxatone was short lasting after each dose. The same differences were reflected in plasma 5-HIAA concentrations and urinary excretion of 3-methoxytyramine and normetanephine. Neither of the compounds tested had any influence on the memory, vigilance, mood, or sleeping habits of the subjects.

Adult↗
PubMed1992

Animal behavioural studies in the evaluation of antidepressant drugs.

Animal behavioural models of psychiatric disorders cannot exactly simulate human psychopathology, but they can be used to evaluate the behavioural changes induced by drugs and to suggest hypotheses about the functions of the CNS and its involvement in psychiatric disorders. This should lead to a more heuristic classification of psychotropic drugs and to clarification of their therapeutic possibilities. The following animal models simulate aspects of depressive disorders and are sensitive to the antidepressant effects of drugs. (i) The forced swimming test: described as 'behavioural despair' on the assumption that the animal has given up hope of escaping. (ii) The 'restraint stress' test: this may indicate a failure to adapt to stress. (iii) The learned-helplessness model: exposed to uncontrollable events, animals exhibit learning performance deficit and behavioural changes, including decreased locomotor activity and loss of appetite. (iv) Waiting behaviour: improvement in the ability to wait for and/or postpone an active response; this could be related to the reported beneficial effects of antidepressants on impulsive behaviour.

Animals↗
PubMed1992

Comparative study of the psychomotor and antistress effects of ritanserin, alprazolam and diazepam in healthy subjects: some trait anxiety-independent responses.

The new potential anxiolytic ritanserin was studied in a double-blind manner vs. alprazolam, diazepam and placebo in 23 healthy subjects. The subjects belonged either to a high anxiety level group or a low anxiety level group, in order to study the effect of the anxiety level on the pharmacodynamic responses. The assessments included cognitive function (memory tests), psychomotor performance [Critical Flicker Fusion (CFF), Choice Reaction Time (CRT)], subjective ratings of alertness and overnight sleep and stress paradigm. Ritanserin (10 mg), alprazolam (0.75 mg), diazepam (10 mg) and placebo were given as single oral doses following a latin square design. Groups were well contrasted on the Cattell anxiety scale and were not overlapping. On no psychometric variable have there been any interactions between the anxiety level and the drug factor. At baseline an anxiety-related difference between the two groups was observed: lower CFF value in the high anxiety group (-1.4 Hz). Both benzodiazepines impaired psychomotor assessment and memory function and increased sleepiness. Ritanserin decreased CFF values without significantly affecting CRT on which nevertheless a trend to impairment was observed. Memory tests, and subjective ratings of alertness were unaffected by ritanserin. A trend to an antistress effect was observed on electrodermogram after ritanserin. Both benzodiazepines decreased central nervous system arousal and memory while ritanserin was inactive except on CFF. Recent data support the hypothesis that 5-HT2 blockers decrease pupil diameter which is a well known covariate of flicker frequency.

Acoustic Stimulation↗
PubMed1991

Is there a relationship between 5-HT1B receptors and the mechanisms of action of antidepressant drugs in the learned helplessness paradigm in rats?

The present study was undertaken to investigate, in the learned helplessness paradigm, (1) the effects of CGS 12066B, a selective 5-HT1B receptor agonist administered alone, and (2) the effects of CGS 12066B co-administered with tricyclics (clomipramine, imipramine) or 5-HT re-uptake blockers (citalopram, fluvoxamine). The results showed that (1) the selective 5-HT1B agonist failed to reverse the escape deficit, and (2) in the drug interaction studies, CGS 12066B did not modify the ability of tricyclics to reverse the escape deficit. The 5-HT1B agonist, however, did significantly reduce the ability of 5-HT re-uptake blockers to reverse the escape deficit. These results suggest that modulation of 5-HT1B sites might modify the enhancement of 5-HT neurotransmission by antidepressants, particularly 5-HT re-uptake blockers.

Animals↗
PubMed1991

Safety signal withdrawal: a behavioural paradigm sensitive to both "anxiolytic" and "anxiogenic" drugs under identical experimental conditions.

A new method involving the blockade of operant behaviour induced by the withdrawal of a conditioned signal for safety without presentation of a punishment signal has been developed for studying drugs with anxiolytic or anxiogenic properties. For this purpose, rats were trained under two alternating components of a multiple schedule of reinforcement FR8 (food)/FR1 (food) + RR 50% (shocks randomly delivered with 50 +/- 15% of the presses). The nonpunished and punished periods were signalled by one cue light above the right lever (safety signal) or the left lever (punishment signal), respectively. On the test session (safety signal withdrawal), the safety signal was turned off at the end of the first nonpunished period, but the punishment signal was not presented (every press was food rewarded and no shocks were delivered). During this period (4 min), rats exhibited a strong blockade of responding that lessened over time. This suppression seemed not to be caused by intervening events such as novelty, temporal conditioning, schedule of food delivery or ambiguity of the signal presented. The behavioural blockade induced by withdrawal of the safety signal was reduced by benzodiazepines: diazepam (0.5-4 mg/kg), chlordiazepoxide (4-8 mg/kg), nitrazepam (0.25-2 mg/kg), alprazolam (0.25-1 mg/kg), and partial agonists at benzodiazepine receptors: bretazenil (0.125-8 mg/kg) and ZK 91296 (32-64 mg/kg). Various 5-HT-related drugs also lessened the behavioural blockade:pCPA (3 x 150 mg/kg) and the 5-HT1A receptor agonists, buspirone (0.25-2 mg/kg), gepirone (0.25-1 mg/kg) but not 8-OH-DPAT. Compounds that may cause anxiety in humans further enhanced the blockade of lever pressing induced by the safety signal withdrawal at doses that did not modify baseline responding: d-amphetamine (0.125-0.5 mg/kg), caffeine (16 mg/kg) and picrotoxin (1 mg/kg). FG 7142 (8 mg/kg) and CGS 8216 (2-8 mg/kg) decreased responding during both components of the session. Therefore, the present paradigm seems sensitive to both "anxiolytic" and "anxiogenic" effects of drugs under identical procedural conditions.

Animals↗
PubMed1991

Antidepressant-like effects of buspirone mediated by the 5-HT1A post-synaptic receptors in the learned helplessness paradigm.

The 5-HT1A receptor agonists buspirone and 8-OH-DPAT have strong effects on serotoninergic systems. Mediated by both pre- and post-synaptic 5-HT1A receptors, these pharmacological effects might predict both antidepressant and antianxiety activities. In animal models sensitive to antidepressant drugs, the 5-HT1A agonists administered i.p. have been shown to mimic the behavioral effects of tricyclics. In the present study, the learned helplessness paradigm was used to assess the possible role of pre- or post-synaptic 5-HTIA receptors in this effect. The ability of buspirone compared with 8-OH-DPAT to reduce helpless behavior was investigated after local microinjections (0.1 or 1.0 micrograms in 0.5 microliters) into the raphe nuclei or into the septum. The results indicate that microinjections of buspirone or 8-OH-DPAT into the raphe nuclei did not reverse helpless behavior; in contrast, microinjections of both 5-HTIA agonists into the septum reverse helpless behavior. These results suggest that antidepressant-like properties of buspirone and 8-OH-DPAT may be mediated, in this test, by the post-synaptic 5-HTIA receptors through functional enhancement of the 5-HT transmission.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1991

The alpha 2-adrenergic receptor antagonist yohimbine inhibits epinephrine-induced platelet aggregation in healthy subjects.

Onset of sudden death, myocardial infarction, and stroke occurs more likely in the morning hours. Similarly, a morning increase in epinephrine-induced platelet aggregation was observed accompanied by an increase in plasma catecholamines. Inhibition of the morning increase in platelet aggregation would be of therapeutic benefit. In this study the effect of the selective alpha 2-adrenergic receptor antagonist yohimbine on platelet aggregation was evaluated in healthy subjects. Yohimbine administered orally selectively antagonized epinephrine but not collagen, arachidonic acid, or adenosine diphosphate-induced ex vivo platelet aggregation. The lowest dose of yohimbine that significantly inhibited epinephrine-induced platelet aggregation was 8 mg. The inhibitory effect of yohimbine on platelet aggregation lasted 10 hours with the 12 mg dose. At the doses studied (4, 8, and 12 mg), yohimbine did not modify blood pressure, standing heart rate, or plasma catecholamine or glucose concentrations. Twelve milligrams of yohimbine moderately but significantly accelerated supine heart rate (mean maximal increase, 7 +/- 3 beats/min). Further clinical studies are needed to evaluate whether bedtime administration of 12 mg yohimbine may block the morning increase in epinephrine-induced platelet aggregation.

Administration, Oral↗
PubMed1991

Interactions of flerobuterol, an antidepressant drug candidate, with beta adrenoceptors in the rat brain.

Interactions of dl-flerobuterol with central beta adrenoceptors were investigated. It inhibited the binding of [3H]CGP 12177, a selective beta adrenoceptor ligand, to membranes prepared from rat cerebral cortex, cerebellum, heart and lung. The affinity of dl-flerobuterol was very close in all tissues (Ki approximately 1 microM). In cerebral cortex, binding inhibition of [3H]CGP 12177 was stereospecific, l-flerobuterol (Ki = 483 nM) being 70-fold more potent than d-flerobuterol (Ki = 34 microM). Moreover, dl-flerobuterol (Ki = 926 nM) was 7-fold less potent than isoproterenol (Ki = 140 nM) to displace [3H]CGP 12177 binding, but 5-fold more potent than salbutamol (Ki = 4600 nM). Flerobuterol did not inhibit the radioligand binding to the other receptors at the highest concentration tested, thus leading to a very high beta adrenergic selectivity. Flerobuterol increased the concentration of cyclic AMP in slices of rat cerebral cortex in a dose-dependent manner; this effect was antagonized by atenolol and propranolol. Compared to isoproterenol or norepinephrine, which produced cyclic AMP maximal increases of 380 and 460%, respectively, it showed a weaker activity with a maximal stimulation obtained at 100 microM, corresponding to a cAMP increase of 140% over basal value (100%). These data revealed that flerobuterol possessed a beta adrenergic agonist activity. Moreover, it antagonized competitively the isoproterenol- or norepinephrine-stimulated accumulation of cAMP. At low concentrations of isoproterenol or norepinephrine, the stimulation of adenylate cyclase was only due to the action of flerobuterol, but at higher concentrations, the response of isoproterenol or norepinephrine was competitively blocked by flerobuterol. At 10 microM, isoproterenol surmounted fully this antagonism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1991

Pharmacokinetics of prednisone and prednisolone in bullous pemphigoid patients.

The purpose of this prospective study was to attempt to evaluate a possible relationship between corticosteroids pharmacokinetics parameters and clinical efficacy in bullous pemphigoid (BP) patients. Sixteen BP patients took part in the study. Prednisone (Cortancyl, Laboratoire Roussel) was given orally (1 mg/kg/day) in a single morning dose. Eleven blood samples were collected over 24 h for the pharmacokinetic studies on day 1 (first day of treatment) and on day Y (after the clinical evaluation). Efficacy was evaluated as the number of new skin blisters on day 1 and on day X which was either the day of cure, i.e. no blisters (responders), or the day of treatment failure, i.e. persistence of blisters (non-responders). Prednisolone (PO) was assayed using high-performance liquid chromatography (HPLC). Areas under the plasma concentration time curves (AUC) and plasma half-lives were estimated using a model independent approach. In responder patients, PO AUC values were 6,225.5 +/- 575.5 ngh/ml, range 3,933-9,080.5 on day 1 and 5,687 +/- 535 ngh/ml, range 4,513.5-9,828.5 on day Y. There was a significant correlation (0.87) between the number of skin blisters on day 1 and the time required for their resolution. The pharmacokinetics and clinical data suggest that a "therapeutic" AUC value was necessary to achieve clinical efficacy and that the duration of treatment depended on the number of blisters on day 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Tricyclic antidepressants, thyroid function, and their relationship with the behavioral responses in rats.

We first studied the effects of tricyclic antidepressants (TCAs) on thyroid function in rats in the learned helplessness paradigm. TCAs (clomipramine 32 mg/kg, desipramine 16, 24 mg/kg, or imipramine 8, 16, 32 mg/kg per day) were injected IP for 5 consecutive days. Blood samples were collected 1 hr after the last administration of the antidepressant for radioimmunoassay determination of triiodothyronine (T3) and thyrotropin. Whereas inducing helplessness did not result in any change in T3 and thyroid-stimulating hormone (TSH) levels, TCA therapy dose dependently decreased the T3 levels without changing TSH levels in helpless animals and in naive control rats. To further the investigation, the effects of TCAs on thyroid function were examined using two models of experimentation, one involving diabetes induction, the other using food deprivation; both are known to induce a resistance to TCAs that is reversible under T3 treatment. In both models, a decreased T3 level existed prior to the TCA administration. Although they had no effect on behavior, TCAs further decreased the T3 levels in diabetic and food-restricted rats. This study confirms that TCAs decrease thyroid function and suggests that the antidepressant effect of TCAs is not related to their T3 decreasing effects.

Animals↗
PubMed1990

Involvement of angiotensin-converting enzyme inhibition in reversal of helpless behavior evoked by perindopril in rats.

Several clinical investigations have suggested that captopril, an angiotensin-converting enzyme inhibitor (ACEI) currently used as an anti-hypertensive agent, exhibits antidepressant properties in humans. In the present study we evaluated the action of perindopril, another ACEI, and two of its metabolites, the di-acide form perindoprilat, which possesses ACE inhibitory properties, and BDM-4, an inactive metabolite, in the learned helplessness paradigm. In order to confirm a possible action of these drugs via dipeptidyl carboxypeptidase inhibition, we also investigated two inactive analogues of perindopril and perindoprilat. Perindopril (0.06-8 mg/kg per day) and perindoprilat (0.25-8 mg/kg per day) induced a reversal of escape deficits. BMD-4 and two analogues failed to reverse helpless behavior. These results support the hypothesis that ACE inhibition is a key factor in the behavioral antidepressant-like activity of perindopril and perindoprilat.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Antidepressant-like action of 8-OH-DPAT, a 5-HT1A agonist, in the learned helplessness paradigm: evidence for a postsynaptic mechanism.

In animal models of depression, the 5-HT1A agonists, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), buspirone, gepirone and ipsapirone administered i.p. have been shown to mimic the behavioural effects of antidepressants. For instance, in the present study, using the learned helplessness paradigm, 8-OH-DPAT dose-dependently reversed helpless behaviour. To assess the possible role of pre- or postsynaptic 5-HT1A receptors in this effect, the ability of 8-OH-DPAT to reduce helpless behaviour was investigated following (1) i.p. administration (0.125 or 0.25 mg/kg/day) in rats whose ascending 5-HT neurons were partially destroyed by previous 5,7-dihydroxytryptamine (5,7-DHT) injection (5 micrograms free base in 0.6 microliter) into the raphe nuclei or (2) after local microinjection (0.1 or 1.0 microgram in 0.5 microliter) into the raphe nuclei or into the septum. The reversal of helpless behaviour by 8-OH-DPAT (i.p.) was still observed in 5,7-DHT-treated rats with telencephalic 5-HT uptake reduced by 50-75% depending on the region. 8-OH-DPAT microinjected into the raphe nuclei did not reverse helpless behaviour; in contrast, 8-OH-DPAT microinjected into the septum reversed helpless behaviour. These results suggest that the ability of 8-OH-DPAT to reverse helpless behaviour probably involved the stimulation of postsynaptic rather than presynaptic 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1990

Captopril as an antidepressant? Effects on the learned helplessness paradigm in rats.

Several clinical investigations have suggested that captopril, an angiotensin-converting enzyme inhibitor (ACEI), currently used as an antihypertensive agent, exhibited anti-depressant properties in humans. The present experiment was evaluated for potential antidepressive activity of captopril on the learned helplessness paradigm in rats. Captopril (8, 16, 32 mg/kg/day, IP) induced a reversal of escape deficits but did not affect significantly the motor activity, suggesting that this effect was not due to motor stimulation. This antidepressant-like activity was comparable to that of imipramine (16, 32 mg/kg/day, IP). Naloxone (0.5; 1 mg/kg, IP) blocked the effect of captopril (16 mg/kg, IP) in this test. These results suggest that an opioid mediation could be responsible at least in part for its behavioral effect.

Animals↗
PubMed1990

Reversal of helpless behavior by serotonin uptake blockers in rats.

Serotonergic systems are thought to be involved in the mechanisms of action of antidepressants in humans. There is little evidence, however, to suggest that serotonin uptake blockers are efficacious in animal models of depression. To further explore the antidepressant activity of these drugs, four compounds from this class (citalopram, fluvoxamine, indalpine or zimelidine) were tested in rats subjected to helplessness training. Rats were first exposed to inescapable shocks and 48 h later, shuttle-box training was initiated to evaluate escape learning. Twice-daily IP injections of citalopram (1 mg/kg), fluvoxamine (4 mg/kg), indalpine (1 and 2 mg/kg) and zimelidine (1 and 2 mg/kg) reduced escape deficits in a manner similar to that produced by the tricyclic antidepressants desipramine and clomipramine. Reversal of escape deficit by serotonin uptake blockers was observed only when the drugs were administered after the shuttlebox sessions. At higher doses, the four serotonin uptake blockers were without effect. These data suggest that serotonin uptake blockers exert antidepressant-like effects in animals but only when they produce a moderate stimulation of serotonin neurotransmission.

Animals↗
PubMed1990

Evaluation and comparison of the interaction between alcohol and moclobemide or clomipramine in healthy subjects.

The interaction of clomipramine and moclobemide with alcohol was compared in a double blind parallel groups study in 24 healthy volunteers. Moclobemide was given at the highest recommended therapeutic dose (200 mg t.i.d.) and clomipramine in a subtherapeutic dose (25 mg b.i.d.) because of its poor tolerance in healthy subjects. Psychometric evaluations were performed during a placebo run-in phase; after a 5-day treatment period; assessments were made before, and again 1 h and 4 h after alcohol ingestion. Alcohol doses were pre-determined for each subject in order to produce a blood alcohol concentration of 0.6 g/l 1 h after alcohol intake and this individual alcohol dose was given on test days. The day before alcohol intake tests for autonomic functions were made to assess the anticholinergic effects of the drugs. Alcohol significantly increased body sway, decreased critical flicker fusion frequency, prolonged choice reaction time, impaired copying skills, impaired memory and increased the subjective feelings of satisfaction and tension. Drugs increased the effect of alcohol on body sway and this was essentially due to clomipramine. Clomipramine both without and with alcohol increased body sway, prolonged choice reaction time more than did moclobemide. Clomipramine seemed to diminish alcohol-induced memory impairment in one of the memory tests used. Subjects taking clomipramine had significantly more adverse effects after alcohol ingestion than did subjects of the moclobemide group. In contrast to moclobemide, clomipramine produced a moderate but significant drop in standing systolic blood pressure and a clear inhibition of salivary excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Alterations in beta-adrenergic sensitivity and platelet alpha 2-adrenoceptors in obese women: effect of exercise and caloric restriction.

1. Peripheral adrenergic responses were studied in eight obese women before and after 15 days of caloric restriction (2500 kJ/day) and in eight sex- and age-matched lean controls. 2. beta-Adrenergic sensitivity (defined as the dose of isoprenaline required to increase resting heart rate by 25 beats/min) was evaluated before and after the diet. Density and affinity (determined as the apparent dissociation constant) of platelet alpha 2-adrenergic receptors, and plasma adrenaline and noradrenaline levels, were measured after overnight bed-rest and after 9 min of standardized exercise performed before and after the low caloric diet. 3. Before the diet basal antecubital venous plasma noradrenaline concentrations were lower in obese women when compared with lean women (0.94 +/- 0.06 vs 1.27 +/- 0.17 nmol/l, P less than 0.02). Isoprenaline sensitivity did not differ between lean and obese women. 4. At rest, platelet alpha 2-adrenoceptor density was lower in overweight than in lean women (129 +/- 21 vs 168 +/- 16 fmol/mg of protein, P less than 0.02). Exercise significantly increased platelet alpha 2-adrenoceptor density and decreased affinity in lean women. This decrease correlated with the rise in plasma noradrenaline. 5. In obese women exercise did not modify platelet alpha 2-adrenoceptor density or affinity, despite a significant increase in plasma catecholamines. However, the increase in plasma noradrenaline during exercise was lower in obese women. 6. The low caloric diet produced a beta-adrenergic supersensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗