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Biomedical subjects

R Cespuglio

Publications and source records attributed to R Cespuglio.

101 records · Page 6Linked to original sources
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↗
PubMed1976

Evidence for the presence of eye movement potentials during paradoxical sleep in cats.

1. Phasic activities related to eye movements in the dark in abducens nucleus (N.VI), lateral geniculate body (LGB), visual cortex, and lateral rectus muscle were analyzed in 18 cats with chronically implanted electrodes during waking and sleeping. 2. N.VI waves, both during waking and sleeping, were multiphasic, and two distinct wave forms were noticed on either side of the pons. The N.VI waves preceded each ocular movement by 10--20 msec. 3. Both during waking and paradoxical sleep (PS), N.VI waves always preceded those occurring in the LGB. During waking, eye movement potentials (EMPs) in LGB followed the onset of the N.VI wave with a long (greater than 60 msec) and variable latency, but followed the end of the same wave with a rather constant delay (about 20 msec). During PS, two distinct populations of latency were observed between onset of the pontine waves and that of LGB waves. The latency of one population was less than 35 msec, and of the other more than 66 msec. 4. Since the LGB waves following N.VI waves with a long latency were similar in a number of respects to EMPs during wakefulness (EMPw), they were judged to be EMPs (EMPps), and were distinguished from LGB PGO waves, which followed N.VI waves with a short latency. Cortical EMPps were observed as well, but occurred about 8--10 times less frequently than the PGO wave. 5. In the light of the present results, the mechanisms responsible for EMP and PGO wave activities are discussed.

Abducens Nerve↗
PubMedDate not supplied

A monoclonal antibody directed against CLIP (ACTH 18-39). Anatomical distribution of immunoreactivity in the rat brain and hypophysis with quantification of the hypothalamic cell group.

After the recent demonstration of the facilitatory effect exerted by corticotropin-like intermediate lobe peptide (CLIP or adrenocorticotropic hormone (ACTH) 18-39) on paradoxical sleep in the rat (Chastrette and Cespuglio, 1985), we undertook the production of monoclonal antibodies against this peptide. Wistar rats were immunized against CLIP and their spleen cells fused with mouse myeloma cells. After recloning, 25 supernatants were found to give positive immunohistochemical reactions in the rat brain. In immunohistochemical tests performed by preabsorption, the 25 supernatants presented similar properties, i.e. recognized CLIP, ACTH (1-39) and ACTH (25-39), but not ACTH (1-24) and the C-terminal fragment (34-39). We assume that the epitope(s) recognized by the 25 supernatants is (are) located between the amino-acids Asn25 and Ala34 of the CLIP molecule. The immunoreactivity observed in the rat brain and hypophysis with this antibody was distributed with a pattern quite similar to that described for anti-ACTH antibodies. A main group of immunoreactive cell bodies was located in the mediobasal hypothalamus and a small group in the nucleus of the solitary tract. Immunoreactive fibres were distributed from the olfactory nucleus to the spinal cord and formed particularly rich networks in the hypothalamus and preoptic area. Among other locations, immunoreactive axons were also present in the brainstem centres involved in the control of the sleep-waking cycle, which is in accordance with the influence of CLIP on paradoxical sleep. Using Abercrombie's formula, the number of immunoreactive cells in the mediobasal hypothalamus was estimated at about 3000 neurons. We conclude that our monoclonal anti-CLIP antibody can be considered as a good marker of proopiomelanocortin neurons.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Genetic study of paradoxical sleep in mice. Connection with coloration genes].

The study of Paradoxical Sleep (PS) from 94 male mice belonging to five inbred strains: C57BR/cdOrl (BR), BALB/cOrl (C), AKROrl, A/JOrl (A/J) and C57BL/6-c2J (B6-c2J), reciprocal F1 hybrids between BR and C strains and backcrosses between F1 hybrids and BR or C was carried out. The results showed that 1) night PS duration was independent from that of day PS; 2) C type of PS seemed to be dominant over BR type; 3) C type is linked to the albino gene; and 4) the albino gene, per se, is not involved in PS regulation. From these results a two locus model was elaborated. This model explains most of the results. The nature of such a genetic support was discussed.

Animals↗
PubMedDate not supplied

[Emotional stress and sleep: a study of adrenalectomized rats].

Polygraphic recordings were performed during 12-h dark period in 18 adrenalectomized rats with implanted electrodes for ECoG and EMG under normal conditions and following 1-h immobilization period. The exposure of rats to emotional immobilization stress evoked a highly significant increase in sleep which was especially pronounced for the slow wave sleep (about 40% above the control value). The immobilization effect was completely abolished by preliminary treatment with dexametazone (1 mg/kg subcutaneously). Thus, adrenal steroids are involved into the interrelation between the emotional stress and sleep as a link in a negative feedback loop.

Adrenal Glands↗