Search PubMed⌕ Search

Biomedical subjects

M Jouvet

Publications and source records attributed to M Jouvet.

At least 289 records · Page 16Linked to original sources
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

Increase of ornithine decarboxylase activity elicited by reserpine in the peripheral and central monoaminergic systems of the rat.

Ornithine decarboxylase activity was increased about tenfold in adrenal glands and in brain regions preponderantly containing aminergic neurons, by a single dose of 16 mumol/kg of reserpine. Maximal enzyme activity in the adrenal glands was observed at about 8 hr after reserpine administration. The ornithine decarboxylase activity-time curves in the brain regions showed a concomitant polyphasic course, with the highest maximum at 12 hr postinjection. Ornithine decarboxylase induction is discussed as an early event in the cascade of molecular events preceding the induction of cell typic enzymes.

Adrenal Glands↗
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

Reversible blockade of PGO waves and concomitant modifications of thalamic unit activity in chronic cats.

The reversible blockade of geniculate PGO waves was carried out by localized cooling of the ponto-geniculate pathways during paradoxical sleep in chronic cats. In parallel, long-term recordings of unit activity were performed in non-specific visuooculomotor thalamic structures where no PGO waves occurred. Blockade of geniculate PGO waves is concomitant with a preferential modification of the phasic discharge of the unit activity (i.e. time-locked with rapid eye movements) when compared to the tonic discharge (i.e. without rapid eye movements). These results suggest that pontine generators of PGO waves could act upon every neuron of the central nervous system. The significance of such an extensive ascending system, the blockade of which does not interrupt paradoxical sleep episodes, still remains puzzling.

Afferent Pathways↗
PubMed1977

Afferent connections of the nucleus raphe dorsalis in the cat as visualized by the horseradish peroxidase technique.

Using a retrograde tracer technique with protein horseradish peroxidase (HRP), attempts were made to determine afferent projections to the nucleus raphe dorsalis (NRD). As a control, the injection of the HRP was also made into one of the following structures adjacent to the NRD: (1) mesencephalic periaque ductal gray; (2) nucleus linearis intermedius; and (3) third cranial nucleus. The present results indicate that the NRD, particularly is rostral part, receives direct projections arising from: (1) locus coeruleus complex (locus coeruleus, locus coerulus alpha, and locus subcoeruleus); (2) parabrachial nuclei (nucleus parabrachialis lateralis and medialis); (3) nucleus laterodorsalis tegmenti; (4) griseum centrale pontis, particularly the caudal part of the nucleus incertus; (5) substantia nigra; (6) lateral habenular nucleus; (7) hypothalamic areas, particularly dorsal and lateral hypothalamic areas; (8) preoptic areas; (9) anarea dorso-lateral to the inferior olivary complex and medial to the lateral reticular nucleus; and (10) raphe nuclei; particularly nucleus linearis intermedius, centralis superior, pontis and magnus. The present findings thus confirm some previous reports on the afferent projections to the NRD described in the cat and rat, and further indicate the richness of afferent connections of the NRD. Some problems of the peroxidase technique have also been discussed.

Afferent Pathways↗
PubMed1977

Discharge patterns of the nucleus parabrachialis lateralis neurons of the cat during sleep and waking.

Discharge patterns of the nucleus parabrachialis lateralis (PbL) neurons located in the dorsolateral pontine tegmentum were investigated in 7 unrestrained, freely behaving cats with a multiwire electrode bundle method. Among 84 PbL units recorded so far, 31% of the units exhibited a marked reduction or complete cessation of firing during paradoxical sleep (PS) (PS-off cells), while 55% of the units exhibited an increase of firing during PS (PS-on cells) as compared with quiet wakefulness (QW) and slow wave sleep (SWS). The remaining 14% of the PbL units exhibited no remarkable change of firing rate and pattern during the sleep-walking cycle. The PbL PS-off cells were further characterized by a slow and regular firing pattern during QW and SWS, and they were similar in several respects to the PS-off cells reported in the nucleus raphe dorsalis and locus coeruleus complex. Six of the PbL PS-on cells were tightly phase-locked with PGO waves, and the spikes preceded by 5-25 msec the onset of the PGO waves recorded in the lateral geniculate nucleus. Seven other PbL PS-on cells were related to the locomotor activity observed in active wakefulness. In light of the present results, the functional significance of the PbL units has been discussed.

Action Potentials↗
PubMed1976

The raphe nuclei of the cat brain stem: a topographical atlas of their efferent projections as revealed by autoradiography.

Stereotaxic injections of [14C]leucine were made in nulei raphe centralis superior, raphe dorsalis, raphe magnus and raphe pontis of the cat. The organization of the regional connections was outlined in a stereotaxic atlas using the autoradiographic tracing method: the majority of the ascending pathways from the rostral raphe nuclei are directed mainly through a ventrolateral bundle via the ventral tegmental area of Tsai, with some lateral extensions to the substantia nigra, and then through the fields of Forel and the zona incerta. More rostrally the fibers are joined to the medial forebrain bundle through the hypothalamic region up to the preoptic area or the diagonal band of Broca. Multiple divisions leave this tract towards the epithalamic or the intralaminar thalamic nuclei, the stria terminalis, the septum, the capsula interna and the ansa lenticularis. The bulk of the rostral projections terminates in the frontal lobe, while some labeling is scarcely distributed throughout the rest of the neocortex. The projections of nucleus (n.) raphe centralis superior are specifically associated with the n. interpeduncularis, the mammillary bodies and the hippocampal formation while the n. raphe dorsalis innervates selectively the lateral geniculate bodies, striatus, piriform lobes, olfactory bulb and amygdala. The rest of the ascending fibers form the centrolateral or the dorsal ascending tracts radiating either in the reticular mesencephalic formation or in the periventricular gray matter. On the contrary there are heavy descending projections from n. raphe centralis superior which distribute to the main nuclei of the brain stem, the central gray matter and the cerebellum. The ascending projections form the caudal raphe nuclei are much less dense. They disseminate mainly in the colliculus superior, the pretectum, the nucleus of the posterior commissure, the preoculomotor complex and the intralaminar nuclei of the thalamus. From n. raphe pontis, a dense labeling is selectively localized at the n. paraventricularis hypothalami with some rostral extensions to limbic areas. Diffuse caudal and rostral projections from both nuclei are observed in the mesencephalic, pontobulbar reticular formation and the cerebellum. The main differences come from the specific localization of their descending bulbospinal tracts inside the lateroventral funiculus of the spinal cervical cord.

Amygdala↗
PubMed1976

[Y-maze learning in two strains of mice. Effects of instrumental and pharmacologic sleep deprivation].

Effects of instrumental and pharmacological deprivation of sleep on Y-maze learning have been studied in two inbred strains of mice (C57BR/cd/Orl and C57BL/6/Orl), having identical sleep rhythms, but mainly differing in their ability to learn. Administration of alpha-methyl-DOPA (100 mg/kg) provokes complete suppression of paradoxical sleep (PS) for 9-11 h. Injection immediately after each training session over the first 5 days caused a delay in acquisition of an active avoidance task in C57BR mice. Treated C57BL/6 mice exhibited a significant facilitation of acquisition. Similar results were obtained by instrumental deprivation of sleep for 10 h.

Animals↗
PubMed1976

A longitudinal study of bioelectric activity in the pre- and post-hatch chick.

A technique for embryonic implantation and the subsequent recording of electrocortical, neck muscle, and ocular activity continously from the 20th day of incubation through hatching and the first few days thereafter is demonstrated. The embryonic maturation of the EEG, with a characteristic muscle burst pattern heralding hatching was found, supporting previous reports obtained with acute preparations. The technique for injection into the chorioallantoic membrane (CAM) vessels or direct deposition onto the CAM is also described. The usefulness of the embryonic neurophysiological implantation coupled with the injection at specific stages of development is discusses as an approach to the understanding of the parameters of the maturation of the sleep-wakefulness cycle, neurochemistry, and behavior.

Animals↗
PubMed1976

Effects of ponto-mesencephalic lesions and electrical stimulation upon PGO waves and EMPs in unanesthetized cats.

1. Phasic waves similar to those observed in the visual system of the awake and sleeping cat ("EMP" and "PGO waves" respectively) were recorded in an area surrounding brachium conjunctivum of the mesencephalic reticular formation (MRF). 2. MRF waves during paradoxical sleep (PS) (MRF PGO wave) occurred 1--2 msec after the waves recorded in the abducens nucleus (N.VI PGO waves), while MRF waves in the alert cat (MRF EMPs) occurred 35--70 msec or more after EMPs in N.VI. 3. Both MRF EMPs in the dark and MRF PGO waves preceded EMPs and PGO waves recorded in the lateral geniculate body (LGB) by 20 msec. 4. There was a time lag of about 40 msec between right and left MRF PGO waves. 5. MRF stimulation elicited short latency responses (5--9 msec) in LGB during waking and sleeping states. During PS, the same stimuli further elicited PGO waves (latency greater than or equal to 40 msec) in the same structure. 6. Stimulation of LGB elicited short latency responses (5--9msec) in MRF. 7. Unilateral MRF lesions reduced by about 50% the number of LGB PGO waves without modifying other characteristics of the PGO wave activity. 8. Following unilateral MRF lesion, LGB EMPs were observed with each eye movement in the dark. However, LGB EMPs ipsilateral to the lesion were greatly reduced in amplitude and followed the EMPs in the opposite LGB by a time lag similar to that observed between bilateral LGB PGO waves. 9. Bilateral MRF lesions completely abolished PGO waves and EMPs observed with the animal in the dark. However, EMPs observed in the light remained unmodified. 10. From the present study it was concluded that LGB and visual cortex gross potential changes related to eye movements in the alert cat have both retinal and non-retinal components. Further, the significance of the MRF area in the mechanisms of EMP and PGO wave activities was discussed.

Abducens Nerve↗
PubMed1976

[Effects of lesions in the pontine tegmentum on the sleep stages in the rat].

1. Limited coagulations of the locus coeruleus and subcoeruleus nuclei have been performed in rats and the sleep-waking cycle was continuously monitored during 9 days. The cortical and diencephalic noradrenaline content was mesured at the termination of the experiment, on the 10th post lesion day. 2. The bilateral destruction of the locus coeruleus is followed by the appearance of a uro-genital syndrome consisting of hema turia, bladder distension and penile erection. The states of sleep are disturbed during the first two days (increase of slow-wave sleep and decrease of paradoxical sleep times) and thereafter return to normal. Additionally, an hyperthermia appears during the third experimental day. The cortical and diencephalic noradrenaline content decrease to 70%. 3. The simultaneous lesion of both locus coeruleus and subcoeruleus nuclei is followed by the appearance of an aphagia adipsia syndrome in addition to the uro-genital syndrome. After these lesions, it is no long possible to find paradoxical sleep episodes in polygraphic recordings while the amount of slow wave sleep is normal. Cortical and diencephalic noradrenaline content decrease more than 50%. 4. In normal rats direct injection of 6 hydroxydopamine directly in both locus coeruleus and nuclei subcoeruleus had no discernable effects either on the behaviour or on the states of sleep. The cortical noradrenaline content decreased 30% below control values. 5. These results are consistent with but do not prove the hypothesis that part of the pontine tegmentum might play an important role in triggering paradoxical sleep episodes. The role of these regions in the regulation of internal temperature, food consumption and bladder motricity is also discussed.

Animals↗
PubMed1976

[Afferent projections to the locus coeruleus nucleus in the cat. Study by the horseradish peroxidase technic].

Using a retrograde tracer technique with horseradish peroxidase, we have revealed some afferent projections to the locus coeruleus complex from the contralateral pontine tegmentum, raphe nuclei, substantia nigra, nucleus of the solitory tract, dorsal motor nucleus of the vagus and other regions of the ponto-bulbar reticular formation as well as from hypothalamic and preoptic areas.

Afferent Pathways↗