PubMed Health⌕ Search

Biomedical subjects

R Cespuglio

Publications and source records attributed to R Cespuglio.

At least 37 records · Page 2Linked to original sources
PubMed1983

Differential pulse voltammetry in brain tissue: III. Mapping of the rat serotoninergic raphe nuclei by electrochemical detection of 5-HIAA.

Differential pulse voltammetry using a new type of carbon fiber electrode, electrochemically treated, is described. The working electrode contains 3 pyrolytic carbon fibers, and passes more current, thus giving a greater sensitivity (with the PRG5 Tacussel polarographic system) than the original monofiber electrodes. It is now possible to investigate brain areas where the monofiber electrodes, working near the limit of PRG5 sensitivity, showed too small a signal. These electrodes have, in addition, better mechanical resistance and can be used (after trypsin cleaning and further electrochemical treatment) for several experiments. Electrochemical measurements made in the nucleus raphe dorsalis before and after treatment with p-chlorophenylalanine, reserpine, clorgyline and clorgyline followed by reserpine, suggest that as in the striatum 5-hydroxyindoleacetic acid (5-HIAA) is mainly responsible for peak 3. The map of the raphe system made with this technique is well correlated with the serotoninergic system of the raphe: the highest peak heights are recorded in the raphe dorsalis.

Animals↗
PubMed1983

[Voltammetric detection of extracellular 5-hydroxyindole compounds at the level of cell bodies and the terminals of the raphe system: variations during the wake-sleep cycle in the rat in chronic experiments].

In rats, chronically implanted for measurements of both voltammetric and polygraphic parameters, variations of the electrochemical signal corresponding to extracellular 5-hydroxyindole compounds (peak 3) were measured during the sleep-waking cycle. The higher amplitude of this signal is always measured during waking. It decreases during slow-wave sleep (20 to 30%) and reaches its lower value during paradoxical sleep (30 to 40%). This phenomenon has been found in all structures investigated, cerebral cortex, caudate nuclei, dorsal hippocampus, suprachiasmatic nuclei, cerebellum, nuclei raphe dorsalis, centralis, pontis and magnus.

Animals↗
PubMed1982

Alterations in the sleep-waking cycle induced by cooling of the locus coeruleus area.

Bilateral or unilateral, localized and reversible cooling (+10 degrees C) of the anterior part of the locus coeruleus area (LCp) in the cat induced, in rapid succession, slow wave sleep (SWS) and a transitory phase of SWS + PGO. These states of sleep were followed in 40-50% of the animals by paradoxical sleep (PS). These effects (on SWS, SWS + PGO and PS) occurred following repetitive periods of short duration cooling and were maintained during long duration cooling (70 min). Unilateral cooling of the ventral part of the locus coeruleus area (LC alpha) and peri-LC alpha induced wakefulness, regardless of the states of sleep in which the cooling was performed. After a cryolesion (-24 degrees C) of the nucleus raphe dorsalis, cooling of the LCp did not induce a hypnogenic effect. Electrical stimulation of the locus coeruleus area, however, always induced wakefulness.

Animals↗
PubMed1981

[Hypnogenic properties of the vasoactive intestinal polypeptide in rats].

The intraventricular injection of 100 ng of vasoactive intestinal polypeptide (VIP) is followed by a significant increase of paradoxical sleep in the Rat. In P. chlorophenylalanine pretreated insomniac Rats which do not present spontaneous paradoxical sleep episodes, intraventricular injection of VIP induces normal quantities of this state of sleep.

Animals↗
PubMed1981

Differential pulse voltammetry in brain tissue. I. Detection of 5-hydroxyindoles in the rat striatum.

In vitro, differential pulse voltammetry combined with electrochemically treated carbon fiber electrodes enabled detection, in different solution of 5-hydroxyindole compounds, of an oxidation peak 3 at +300 mV. In vivo, a striatal peak 3 was also recorded at this potential. Electrolytic or 5,7-dihydroxytryptamine lesions interrupting the medial forebrain bundle (MFB) were followed by a decrease of 65% and 64% in peak height, but not elimination of the peak. Biochemical determinations were significantly correlated to the peak 3 measurements. The existence of peak 3 as well as hydroxyindole compounds in blood suggested a blood contamination under the experimental conditions employed. This possibility is confirmed both by the complete disappearance of striatal peak 3 in animals with the MFB lesioned and surgically prepared a week before recordings, and by biochemical measurements in parachlorophenylalanine-treated or perfused (phosphate-buffered saline solution) animals.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1981

Differential pulse voltammetry in brain tissue. II. Detection of 5-hydroxyindoleacetic acid in the rat striatum.

Differential pulse voltammetry with electrochemically treated carbon fiber electrodes was used to study, in anesthetized rats, the alterations of the striatal electrochemical signal appearing at +300 mV (peak 3), following pharmacological manipulation of the animals. Decreases in peak 3 were obtained after injections of NSD 1015, Ro 4-4602 and Clorgyline. This, in conjunction with biochemical measurements, suggested that 5-hydroxyindoleacetic acid (5-HIAA) is, to a considerable extent, responsible for this electrochemical signal. Increases in peak 3 obtained after reserpine, L-tryptophan and D,L-5-HTP, as well as biochemical data reinforced this hypothesis, as did the detection of peak 3 in cerebrospinal fluid and its increase after probenecid injection. The occurrence of a feed-back mechanism is discussed following injection of D,L-5-HTP.

5-Hydroxytryptophan↗
PubMed1981

In vivo measurements by differential pulse voltammetry of extra-cellular 5-hydroxyindoleacetic acid in the rat brain.

The use of differential pulse voltammetry, performed with electrochemically treated carbon fiber electrodes, enables us to detect in vitro or in vivo, in the striatum of anaesthetized rats, an oxidation peak (3) at a potential of + 300 mV. Electrolytic or 5-7-dihydroxytryptamine lesions of the medial forebrain bundle are followed by a decrease of 59 and 62% respectively of this peak. Biochemical measurements are significantly correlated with the measured peak (3) and decreases. Thus, peak (3) increases obtained after injection of L-tryptophan and/or Reserpine, as well as the decreases observed after injection of Clorgyline or 3-hydroxybenzylhydrazine, confirm that peak (3) is dependent upon 5-hydroxyindoleacetic acid concentration. The detection of a peak (3) in the cerebrospinal fluid and its increase after injection of Probenecid reinforce this conclusion.

5,7-Dihydroxytryptamine↗
PubMed1980

[In vivo measurement, by differential pulse voltammetry, of 5-HIAA in the striatum of the rat].

Differential pulse voltammetry, performed with electrically treated carbon fiber electrodes, enables us to detect in vitro or in vivo in the striatum of anesthetized Rats, an oxidation peak 3 at a potential of +300 mV. Electrolytic, or 5,7-dihydroxytryptamine lesions of the medial forebrain bundle are followed by a decrease of respectively 59 and 62% of this peak. Biochemical measurements are significantly correlated to the measured peaks 3 and troughs. Thus, peak 3 increases obtained after injection of L-tryptophane and/or reserpine, as well as the troughs observed after injection of clorgyline and/or NSD 1015 confirm that the peak 3 is dependent upon 5-hydroxyindolacetic acid (5-HIAA) concentration.

Animals↗
PubMed1980

[In vivo voltametric measurement of ascorbic acid and DOPAC in the striatum of the rat and guinea-pig].

Differential pulse voltammetry was performed with electrochemically treated carbon fiber electrodes. By this technique, ascorbic acid and catechol compounds were resolved in vitro in two distinct peaks. Similar oxidation peaks were obtained in vivo from the striatum of Rats and Guinea-Pigs. From electrochemical and pharmacological observations it is suggested that they correspond to the oxidation of extracellular ascorbic acid and 3,4-dihydroxyphenyl acetic acid (DOPAC).

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

[Effect of cooling and electrical stimulation of nuclei of raphe system on states of alertness in cat].

In cats prepared in a 'semi-chronic' manner (spinal cord transected, brachial plexus sectioned bilaterally) all states of alertness are present; their quantitative evolution is characterized by an immediate postoperative period with continuous wakefulness and a secondary period of recovery of the states of sleep, which are then maintained. In such a preparation, localized moderate cooling (+10 degrees C) of the nucleus raphe dorsalis induces slow wave sleep and paradoxical sleep; the same type of cooling of the nucleus raphe magnus induces wakefulness; however, the electrical stimulation of these two nuclei always induces wakefulness. Cooling of the nuclei raphe centralis or pontis suppresses only the 'ponto-geniculo-occipital' (PGO) waves. Colling of the nuclei raphe obscurus and pallidus induces wakedfulness, but stage I of slow wave sleep may occur. Treatment with p-chlorophenylalanine (PCPA) before making the semi-chronic preparation produces the classical syndrome characterized by cortical activation and continuous discharge of PGO waves; in this case cooling of the nucleus raphe dorsalis no longer induces slow wave sleep but only paradoxical sleep; after injection of DL-5-HTP, slow wave sleep is obtained again through cooling; this effect diminishes progressively.

5-Hydroxytryptophan↗
PubMed1978

[In vivo continuous electrochemical determination of dopamine release in rat neostriatum].

Polarographic micro-electrodes (carbon fiber, o. d. 8 micron) implanted in the Rat caudate nucleus, allowed a practically continuous in vivo monitoring (one measurement every 5 sec.) of the extra-cellular concentration of dopamine released by striatal dopaminergic terminals. Administration of amphetamine produced a reproducible increase of the oxidation current. This effect was suppressed after the selective degeneration of the striatal dopaminergic terminals following the injection of 6-OHDA into the substantia nigra or after inhibition of the synthesis of the amine by alpha methyl-p-tyrosin. After 5 hrs. this drug produced a 70% decrease of the oxidation current.

Animals↗
PubMed1978

Rhythmical activity of the rat's tongue in sleep and wakefulness.

Nine chronically implanted rats were used to study rhythmical activity of suprahyoidal muscles controlling tongue motility. This muscle group exhibited a fixed, regular rhythm of 5--8 c/sec during PS, not during SWS, resembling that observed when the awake rat drank, ate or groomed. In PS the tongue rhythm occurred less frequently than did eye movements and phasic nasolabial muscle activity; when it did, it was associated with such eye movements 80% of the time and 20% of the time before or after an episode of eye movements. A respiratory-related suprahyoidal EMG was observed in one rat to precede the onset of the diaphragm's EMG. Mechanisms for entraining phasic activity of extraocular, nasolabial and suprahyoidal muscles in PS are discussed.

Animals↗
PubMed1977

[Phasic activity in rats].

At the central level, in the rat, phasic activity has been recorded during paradoxical sleep and in acute conditions after injection of reserpine or parachlorophenylalanine. At the external level, during paradoxical sleep, the extraocular muscles lateral rectus, superior rectus and superior oblique are activated in both plastic and tonic manners. The muscles of the whiskers are also activated; these muscular activations are more often than not synchronous with the eye movements (80%). The time distribution of these ocular movements is homogenous. Reserpine induces phasic muscular activations of the extraocular muscles.

Animals↗
PubMed1976

Anatomical organization of the phasic activity produced by reserpine at the level of the oculomotor system.

The organization of the pathways responsible for the transmission of phasic electrical activity at the level of the oculomotor system was studied in the encéphale isolé cat which was injected with reserpine or exhibited spontaneous phases of paradoxical sleep. At the level of the VIth nuclei there are both ipsilateral and contralateral connections deriving from each generator. The ipsilateral pathway transmits an "inhibiting" potential eliciting electromyographic inhibition of the ipsilateral rectus muscle, and the contralateral pathway, an "activating" potential eliciting activation of the corresponding lateral rectus muscle. A medial saggital section from frontal plane APO, extending caudally to the VIth nuclei at frontal plan P9 is necessary to suppress the bilateral synchronization of phasic activities recorded from the VIth nuclei and the activation of the lateral rectus muscles. The areas responsible for phasic activity recorded at the level of the central visual and oculomotor systems have been delimited through brain transections. The pathways responsible for the transmission of phasic activity at the level of the IIIrd and IVth nuclei are contiguous with the ponto-geniculate pathways. This was demonstrated by electrocoagulation.

Abducens Nerve↗