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Biomedical subjects

C Jacquot

Publications and source records attributed to C Jacquot.

At least 91 records · Page 5Linked to original sources
PubMed1991

Indolamines in the cockroach Blaberus craniifer Burm. nervous system--II. Fed and crowded young males in comparison with females.

1. Indolamines were assayed by HPLC-ECD in nervous tissue of fed and crowded young males Blaberus craniifer Burm. 2. In males, as in females housed in the same conditions, levels are depending on both age and region (= ganglia) of the central nervous system. 3. Registered sex differences are discussed in terms of anatomical, physiological and behavioral sexual dimorphism.

Animals↗
PubMed1991

Biogenic amines in newly-ecdysed cockroaches.

1. Simultaneous quantification (HPLC and electrochemical detection) of biological extracts have shown dopamine, N-acetyl dopamine, tryptophan, 5-hydroxytryptamine, a 5-hydroxyindolacetic acid-like substance in nervous tissue and hemolymph of Blaberus craniifer and Periplaneta americana. 2. 5-Hydroxytryptophan was only detected in head and thoraco-abdominal nerve cord. 3. Octopamine, but not N-acetyl-5-HT was quantified in the hemolymph.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Indolamines in the cockroach Blaberus craniifer Burm. nervous system--I. Fed and crowded young females.

1. Indolamine levels were determined in the cerebral ganglion, the thoraco-abdominal nerve cord (except the last ganglion), and the 6th abdominal ganglion of females of Blaberus craniifer. 2. Measurements were made at the imaginal molt and on fed and crowded imagos at 10, 20 and 30 post-imaginal days. 3. Indolamines were found in the nervous system of young females, but 5-hydroxytryptophan was only detected in the thoraco-abdominal nerve cord. 4. Amine levels were related to the age of the cockroach, particularly during this period, to post-ecdysis events and ootheca formation.

Animals↗
PubMed1991

Effect of L-dopa loading on 5-HTP decarboxylation in rat brain areas.

The time course of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in four rat brain areas (hypothalamus, hippocampus, striatum and olfactory bulbs) were investigated after treatment with L-dopa (125 mg/kg, ip) + benserazide (50 mg/kg, ip). 5-HTP levels increased as early as 0.5 h, showed maximum accumulation at 1.5 h and returned to control levels within 4 h, while 5-HT was markedly decreased in all four structures, with a maximum effect at 1.5 h (approximately -70%) in the four areas. The decrease in 5-HT was not accompanied by changes in 5-HIAA levels. In agreement with previous studies, these data demonstrate that L-dopa loading interferes with serotonin metabolism in the rat brain. However, in addition to the releasing action of newly-synthesized dopamine, the accumulation of 5-HTP and the parallel decrease in 5-HT indicate a reduction in 5-HT synthesis. This inhibition could be explained by a competitive effect of L-dopa for aromatic aminoacid decarboxylase activity.

5-Hydroxytryptophan↗
PubMed1991

Establishing the relationship between complement activation and stimulation of phagocyte oxidative metabolism in hemodialyzed patients: a randomized prospective study.

The present prospective study was conducted in order to establish the relationship between complement activation and stimulation of phagocyte oxidative metabolism observed in long-term hemodialysis (HD) patients during the early phase of dialysis with cellulosic membranes. Two groups of 10 randomized (HD) patients treated with cellulosic (Cuprophan, CUP) or synthetic polyacrilonitrile (PAN AN-69) membranes were studied. Leukocyte counts, C3a antigen plasma concentration and whole blood basal and stimulated chemiluminescence (CL) production were determined in blood samples drawn from the fistula before dialysis (T0) and from both the afferent and efferent lines of the dialyser at 15 min (T15) and at the end (Tend) of the dialysis session. This study confirms that, coincident with the nadir of leukopenia observed at T15, dialysis with CUP but not PAN membranes induces a marked rise in C3a antigen levels and profound alterations in whole blood CL production consisting of a dramatic increase in basal CL and a significant loss in CL response capacity to stimulating agents. It further demonstrates that a direct relationship exists between the variations in C3a antigen plasma levels and whole blood CL production observed in the CUP group of patients from T0 to T15 (delta 15) of dialysis. This relationship is characterized by a positive correlation between delta 15 C3a and delta 15 basal CL levels in afferent and efferent lines, and a negative correlation between delta 15 C3a and delta 15 CL response capacity values in the efferent but not afferent line. In contrast, no significant correlation with the type of dialysis membrane could be demonstrated between the variations in polymorphonuclear neutrophil counts and C3a antigen levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1991

Kinetics and brain uptake of COR3224, a new 2-amino-2-oxazoline, in rats.

COR3224, a new 2-amino2 oxazoline derivative, shows antidepressant activity in the rat. This study was designed to analyse the influence of dose ranging on the brain/plasma concentration ratio of this drug. Adult male rats (250-300gr, Sprague Dawley) were given orally 10, 40 and 160 mg/Kg radiolabelled 14C-COR3224 (30 microCi/kg) in aqueous solution and were sacrificed at 0.25; 0.5; 0.75; 1; 2; 4; 6; 8; 12; 16; 24; and 30 hours post dose (5 rats per time). Plasma and brain samples were analysed for total radioactivity (T.R.) by liquid scintillation and for COR3224 (U.P.) by reversed-phase liquid chromatography and electrochemical detection. A linear relationship was found between AUC and doses administered for both TR and UP plasmatic determinations. In opposite, cerebral AUC for TR and U.P were not proportional to dose, and the evolution of the brain/plasma concentration ratios showed higher values for the 10mg/kg dose than for the 40 and 160mg/kg doses.

Animals↗
PubMed1991

[Comparative data on biogenic amines and GABA in three Rodents Filariae].

Detection and quantification of biogenic amines and GABA were carried out on three adult Filariae Litomosoides carinii, Acantocheilonema viteae and Molinema dessetae obtained from Rodents. Catecholamines were under the level of detection. Indolamines and GABA levels depend on species and sex. Results are discussed in relation to the parasitism and localization in the host.

Animals↗
PubMed1990

Changes in hypothalamic neuropeptide Y concentrations induced by cholecystokinin analogues.

Neuropeptide Y (NPY) and cholecystokinin (CCK) are two peptides involved in opposite ways in the control of food intake. A possible interaction between NPY and CCK has not yet been well defined. Two CCK derivatives with agonistic and antagonistic properties were studied with regard to their effects on brain and plasma NPY levels. The CCK agonist decreased NPY levels in plasma and in the hypothalamus but not in the other brain areas assayed. The CCK antagonist reversed the agonist-induced decrease in both plasma and hypothalamus. These results suggest a negative relation between NPY and CCK peptides, which is not surprising given their opposite role in feeding regulation. The hypothalamus, a preferential site of this regulation, appears to be the brain area most involved in the NPY-CCK interaction. The plasma NPY level variations closely reflect the hypothalamic profile, suggesting a direct release of NPY by a mechanism that remains to be investigated.

Animals↗
PubMed1990

Opposite dopaminergic activity in lateral and median hypothalamic nuclei in relation to the feeding effect of D-Ser2-Leu-Enk-Thr6 (DSLET).

The Leu-enkephalin analogue D-Ser2-Leu-Enk-Thr6 (DSLET) had been shown to enhance feeding in rats, increase dopaminergic activity in the striatum like other opiate agonists, and particularly to decrease dopaminergic activity in the hypothalamus. In this study, the latter effect was found to be localized in the hypothalamic nuclei involved in the regulation of feeding such as the paraventricular (PVN), ventromedian (VMH), dorsomedian (DMH) nuclei and the lateral hypothalamus (LH). DSLET produced the same decrease in dopaminergic activity in the LH as in the whole hypothalamus. In the median nuclei (PVN and VMH and to a lesser extent in the DMH), an opposite effect was observed, resembling that in the striatum. The relevance of these opposite variations with regard to the feeding effect of DSLET is discussed. The decreased dopaminergic activity in the LH would appear to be the most specifically related to the behavioural effect given the known role of dopamine in this region. These data reconcile apparently contradictory aspects of the role of dopamine and the functional opposition between the lateral and median hypothalamus in food intake control.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

[One-year treatment of 43 chronic hemodialysis patients with recombinant human erythropoietin].

Twenty men and 23 women aged from 18 to 65 years, who had been under maintenance haemodialysis for 2 to 16 years and whose haematocrit had been below 30 percent for at least 3 months received recombinant human erythropoietin intravenously at the end of each session for one year. Anaemia was corrected in all patients, the delay in response to each dosage variation being about 4 weeks. The necessary maintenance dosage ranged from 96 to 240 u/kg/week. The number of leucocytes increased significantly until the 4th month, from 5880 +/- 1760 to 6600 +/- 1920 per cubic mm (P less than 0.01). During treatment, pre-dialysis blood creatinine concentrations and potassium and phosphate levels rose, while blood calcium levels fell significantly from 2.45 +/- 0.16 to 2.36 +/- 0.19 mmol/l (P less than 0.01). A nonsignificant increase in systolic and diastolic pressures was also observed, from 129 +/- 16 to 134 +/- 18 mmHg (P = 0.06) and from 75 +/- 9 to 78 +/- 10 mmHg (P = 0.07) respectively. Eight patients (18 percent) required antihypertensive drugs or a higher dose of those previously prescribed. There were 7 cases of vascular thrombosis on pre-existing stenosis, and the dosage of heparin during dialysis had to be increased in most patients. This study confirms that erythropoietin plays a major role in the genesis of the anaemia associated with renal failure. The absence of severe complications in this series was probably due to the criteria of inclusion in the study.

Adolescent↗
PubMed1990

High-performance liquid chromatography of a new 2-amino-2-oxazoline: application to pharmacokinetic studies in dogs.

5-(1'-Phenyl-4'-piperazinomethyl)-2-amino-2-oxazoline (1; COR3224), a derivative of 2-amino-2-oxazolines with antidepressant properties in rats, was assayed in plasma by high-performance liquid chromatography. After back extraction, 1 and a ortho-O-methyl derivative of 1 as the internal standard were separated by reversed-phase liquid chromatography and measured by UV detection (235 nm). The method is rapid and specific: the detection was linear in the range 125-1000 micrograms.L-1, with a detection limit of 50 micrograms.L-1. This method allowed the determination of pharmacokinetic parameters in six beagle dogs after intravenous and oral administration of 14C-labeled 1 ([14C]1) in a crossover study. The comparison of the results obtained from total radioactivity counting and unchanged product evaluated by HPLC-UV suggest the presence of metabolites.

Administration, Oral↗
PubMed1990

Reversal of a feeding-reward system by dexfenfluramine: neurochemical involvement.

In addition to its anorectic properties, dexfenfluramine may inhibit some manifestations of feeding-related reward. We attempted to verify this effect by measuring paw-lick latency on the hot plate test in rats conditioned to expect a palatable food. The involvement of variations in beta-endorphinergic, dopaminergic and serotonergic systems was assessed. Despite an inherent effect of increasing paw-lick latency, dexfenfluramine (1.5 mg/kg IP) partly reversed the expectancy-induced increase in this latency. Saline-treated "expectant" rats displayed elevated plasma beta-endorphin levels and reduced hypothalamic 5-HIAA/5-HT and DOPAC/DA ratios. Only the decrease in the DOPAC/DA ratio was reversed by dexfenfluramine, suggesting an involvement of the dopaminergic system in this dexfenfluramine-sensitive reward system.

Animals↗
PubMed1990

A cholecystokinin agonist/antagonist according to dose and time of action: effect on food intake.

A new CCK pseudopeptide (Boc-Tyr (SO3)-Nle-psi-(COCH2) Gly-Trp-Nle-Asp-Phe-NH2) has been described in a previous study as a potent CCK agonist in the peripheral system and as an antagonist in the central nervous system. When administered alone by a peripheral route, this pseudopeptide was found to decrease food intake in free/feeding rats, and thus behaved as a CCK agonist. However, it reversed the decreased feeding effect induced by a full potent agonist (Boc(Nle 28-Nle 31)-CCK26-33). This antagonistic action occurred 3-4 h after treatment, at a time when the agonistic properties of the pseudopeptide alone had disappeared, but when the effect of the full potent agonist remained. The dose-response curve of the antagonistic action was bell-shaped. These results suggest that this new pseudopeptide is not only agonistic in the periphery and antagonistic in the central nervous system as shown in the previous study, but is also both agonistic and antagonistic on the same paradigm according to the dose and time of action.

Amino Acid Sequence↗
PubMed1990

Changes in brain neuropeptide Y induced by cholecystokinin peptides.

Cholecystokinin (CCK) and neuropeptide Y (NPY) are two peptides with opposite effects on the regulation of feeding behaviour. The possible interaction between these two systems has always been controversial. In this study, rat brain NPY levels were assayed after treatment with CCK 8 S and with a potent CCK agonist (Boc-(Nle 28-Nle 31)-CCK 26-33). CCK 8 S and its agonist analogue (50 micrograms/kg i.p.) both decreased hypothalamic and hippocampal NPY levels. This result suggests a negative relationship between NPY and CCK-peptides which is not surprising given their opposite role in the control of feeding. The hypothalamus and secondarily the hippocampus appear to be the site of this interaction; no change in NPY levels was observed in other brain areas (striatum and cortex). The same pattern of variation was found in the plasma, suggesting a direct release from the brain via a mechanism which remains to be investigated. The effect appeared later with the CCK analogue than with CCK 8 S itself; this is not surprising with regard to other behavioural and biochemical effects of the analogue and provides further characterization of its action.

Animals↗
PubMed1990

Effects of a new cholecystokinin analogue (JMV 236) on food intake and brain monoamines in the rat.

JMV 236, a new cholecystokinin-octapeptide-sulfate (CCK 8 S) derivative (Boc-Tyr (SO3)-Nle-Gly-Trp-Nle-Asp-Phe-NH2) has been synthesized in the Centre de Pharmacologie-Endocrinologie (Montpellier). This peptide has been shown to present the same activity as CCK 8 S on pancreatic amylase secretion and has the advantage of a better chemical stability. With a view to further characterization, the effect of JMV 236 on food intake and brain monoamine and metabolite variations was assayed in the rat after intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) administrations. JMV 236 decreased food intake 2 and 3 hours after i.p. administration of 12.5 and 50 micrograms/kg but was inactive after i.c.v. injection. Its global action was similar to that of CCK 8 S, but was less marked with delayed onset of response. As in our previous work with CCK 8 S, JMV 236 was more potent in inducing monoaminergic variations after i.p. than after i.c.v. administration. The main effects were decreases in striatal dopamine metabolite levels and increases in hypothalamic and striatal serotonin metabolite (5-HIAA) levels. These effects are classically observed with CCK 8 S and are described in our previous reports. The interesting peptide will require further characterization and may serve as a possible reference compound for studies on CCK derivatives.

Animals↗
PubMed1990

Cholecystokinin-induced variations in hypothalamic serotonergic system of the "cafeteria" rat.

Cholecystokinin octapeptide sulfate (CCK 8 S) appears to act via a serotonergic mechanism on several behavioral paradigms, including satiety. In the present study, CCK 8 S was found to induce slight nonsignificant serotonergic changes in hypothalamic nuclei of the normal rat. In the "cafeteria" rat, however, it increased both 5-HT and 5-HIAA levels in the ventromedial hypothalamus (VMH), 5-HT levels in the paraventricular nucleus (PVN) and decreased 5-HIAA levels in the dorsomedial hypothalamus (DMH). These data suggest that the primary site of action of CCK 8 S is in the median hypothalamus, contrasting with an absence of effect in the lateral hypothalamus (LH). The involvement of 5-HT in the effect of CCK 8 S is further suggested. However, the relationship between these neurochemical changes and CCK 8 S-induced satiety is not clear. Nonetheless, a special sensitivity to CCK 8 S of the obese "cafeteria" rat is evidenced, which contrasts with a reduced response of genetic obesity models.

Animals↗