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Biomedical subjects

B Bioulac

Publications and source records attributed to B Bioulac.

At least 109 records · Page 6Linked to original sources
PubMed1981

[Aphasic-type language disorders associated with lesions of the putamen and caudate nucleus: clinicopathological findings in one case (author's transl)].

Language disorders developed in a patient following a subcortical infarct involving the left putamen and caudate nucleus. Language was abundant and fluent, with many perseverations, semantic and ideation incoherences, and all activities concerned with verbal or non-verbal expression were affected. Lesions were present in the head and body of the caudate nucleus, the whole of the putamen, the anterior nucleus of the thalamus and the superior part of the internal capsule. The disorder was unique in relation to disturbances of the aphasic type observed in extensive thalamic lesions, or in transcortical sensorial aphasia. Physiopathological interpretation is based on the functional role of the putamen-caudate system in the regulation of many types of behaviour: animal experiments and results of applying stimuli in humans suggests a release of the inhibition exerted by the caudate nucleus on the frontal cortex. Lack of comparable clinicopathological data implies that other similar cases must be reported before the specificity of the disorder can be confirmed.

Aphasia↗
PubMed1981

[Angiotensin II and nigostriatal system (author's transl)].

The central renin-angiotensin system is implicated most importantly in the control of water balance, blood pressure and endocrine function (AVP and ACTH). Several central structures are sensitive to angiotensin II (A II), principally: the subfornical organ, the vascular organ of the lamina terminalis, the area postrema and the preoptic area. Furthermore, binding studies with radio-active ligands and also immunohistofluorescence have shown respectively the presence of A II receptors and immunoreactive material bound by A II antibodies in other central structures, and in particular parts of the motor system. In the present study, a double approach, both electrophysiological and biochemical, was used to investigate the possible role of the peptide A II in the neostriatum of the rat. 1 Microiontophoretic application of A II was shown to modify the spontaneous activity of some neurones (15/68) in the neostriatum. Generally, the action of A II was inhibitory and the inhibition was blocked by Sar1-Ileu8-A II, a specific A II antagonist. 2 Angiotensin II 10(-6) M; 10(-5) M; 5.10(-5) M) stimulated the spontaneous release of 3H-dopamine continuously synthetized from 3H-tyrosine in striatal slices of the rat. The A II-evoked release of 3H-dopamine was prevented when slices were superfused with a calcium-free medium containing EGTA. It was also suppressed in the presence of the specific antagonist Sar1-Ileu8-A II. 3 Kainic acid lesion of the intrastriatal cell bodies produced a moderate decrease of A II in the striatum (38%) whilst the activity of the converting enzyme decreased dramatically (-68%). These results suggest that there are angiotensin-containing nerve endings in the neostriatum, and that the cell bodies of such nerves are located outside this structure. Their functional role is discussed.

Angiotensin II↗
PubMed1980

Evidence of a direct action of angiotensin II on neurones in the septum and in the medial preoptic area.

Angiotensin II (AII) was microiontophoretically applied on neurones located in the septum and the medial preoptic area (MPOA). All the septal neurones sensitive to AII (15/37) responded by an inhibition to the peptide application. Of 44 units tested in the MPOA 21 cells (48%) were sensitive to AII and responded either by an increase (11/21) or decrease (10/21) in their firing. The specificity of these responses were ascertained by simultaneous application of the antagonist Sar-Ile-Angiotensin II. These data suggest that Angiotensin II acts directly on neurones of the septum and medial preoptic area, structures implicated in the control of drinking behaviour.

1-Sarcosine-8-Isoleucine Angiotensin II↗
PubMed1980

Serotoninergic dysfunction in the 47, XYY syndrome.

In six XYY patients suffering from aggressiveness and admitted by order of law into a security setting for acts of violence, the estimation of cerebrospinal fluid amine metabolites before and after a probenecid test revealed a clear decrease in the turnover of central serotonin (5-HT) while that of dopamine (DA) was unchanged. The treatment with the 5-HT precursor, L-5-hydroxytryptophan (L-5-HTP), in five of the XYYs resulted in a clinical status equivalent to that observed when the patients were previously treated by conventional neuroleptics.

5-Hydroxytryptophan↗
PubMed1979

Activity of postcentral cortical neurons of the monkey during conditioned movements of a deafferented limb.

Unit recordings were performed in the sensorimotor cortex of awake monkeys during performance of learned movements of the contralateral arm. The movements were triggered by a sound stimulus. The neuronal discharge in association with movement was observed before and after deafferentation (C2--T5) of the operant limb. Whereas neurons recorded in the motor cortex (area 4) and in the parietal association cortex (area 5) still modified their activity in relation to movement performed by the deafferented arm, the neurons recorded in the primary sensory cortex (areas3, 1 and 2) showed no activity change in relation to movement after deafferentation. This finding strongly suggests that modification of discharge of postcentral neurons seen during ballistic arm movement is mainly the result of input from the moving limb (peripheral feedback) and not the result of input from other structures of the central nervous system (internal feedback).

Afferent Pathways↗
PubMed1979

Chronic methods to study the release of catecholamines from the neostriatum in nonanaesthetized monkeys (Macaca mulatta).

The present report describes two methods allowing the chronic collection of catecholamine (CA) released from the neostriatum in the nonanaesthetized monkey (Macaca mulatta). In both methods the monkeys were placed in a restraining chair. Indwelling electrodes allowed the correlation of behavioural observations with polygraphic recordings. The first method uses a special superfusing cup permanently implanted on the lateral surface of the caudate nucleus, which permits the demonstration of spontaneous and D-amphetamine-induced release of (3H)-dopamine (DA) newly synthesized from L-(3,5-3H)-tyrosine over a period of six days. In the second method the collection of unlabelled CA is carried out by a localized ventricular perfusion. A radio-enzymatic estimation enabled the measurement of unlabelled DA and noradrenaline. With this second method the animals were kept for 25 to 30 days.

Amphetamine↗
PubMed1978

Responses of central neurones to piribedil and 2-bromo-alpha-ergocryptine: comparison with dopamine and apomorphine.

The effects of two putative dopamine receptor agonists, piribedil and 2-bromo-alpha-ergocryptine were studied by means of microiontophoresis. Their effects were compared with those of dopamine and apomorphine on neurones of the frontal cortex and of the caudate nucleus both of which are rich in dopaminergic terminals. Piribedil and S. 584, its dihydroxyphenyl derivative, displayed a potent dopamine-like inhibition in both these areas. 2-Bromo-alpha-ergocryptine exerted significant inhibition on cortical neurones which were spontaneously active but only weak or negligible inhibition on cortical and caudate glutamate-driven units. These observations raise the possibilities that 2-bromo-alpha-ergocryptine (1) mediates its inhibitory effect via a predominant presynaptic action; (2) acts preferentially on cortical neurones.

Animals↗
PubMed1978

Biogenic amines in 47, XYY syndrome.

47, XYYs represent a high percentage of patients admitted in security settings for aggressiveness. By using a polygraphic technique and amine metabolite estimation in the cerebrospinal fluid (CSF), an attempt was made to evaluate the functional activity of the central aminergic system of these patients. No drastic change was observed in sleep patterns of XYYs. The estimation of CSF amine metabolites revealed a normal value for homovanillic acid, but a significant decrease of 5-hydroxyindoleacetic acid turnover.

Adult↗
PubMed1978

Activity of pre-entral neurones in conscious monkeys: effects of deafferentation and cerebellar ablation.

After limb deafferentation, there was no gross alteration in the initiation and performance of a sound-triggered ballistic movement. The pattern of neuronal discharge in the arm area of the motor cortex was not significantly modified. In the absence of cerebellum, the reaction time of motor cortex cells was about 150 msec longer than the reaction time observed in normal and deafferented animals. This was associated with an equal retardation in the onset of ENG changes in the limb muscles. This observation is compatible with the idea that the motor cortex is normally situated downstream to the cerebellum in the initiation of some movements. However, the motor cortex is necessary for the initiation and execution of simple sound-triggered movements since its removal results in a permanent inability to perform the task. Finally, in the absence of peripheral feedback, the pattern of motor output to the agonistic and antagonistic muscles was initiated normally and thus appeared to be preprogrammed centrally. The importance of the motor cortex as a "reflex center" in the control of slower movements is obviously not challenged by these observations since the motor task that we have used depends very little or not at all on sensory feedback (Stark, 1968). What these results indicate, however, is that the execution of some voluntary fast ballistic movements can be entirely preprogrammed independently of peripheral and cerebellar influences, and that the program, which is mainly concerned with generating velocity signals, appears to require the integrity of the motor cortex for its execution.

Afferent Pathways↗
PubMed1977

[Effect of some phosphonic amino acids on the activity of central neurons].

Microiontophoretic applications of DL-2-amino-3-phosphonopropionic, DL-3-amino-4-phosphonobutyric, aminomethylphosphonic, 2-aminoethylphosphonic and 3-aminopropylphosphonic acids in the course of extracellular recordings of central neurons in the Rat resulted in effects which appeared similar to those observed with their carboxylic analogs. The involvement of the same post-synaptic receptors is suggested.

Amino Acids↗
PubMed1975

Morphine excitation in the cerebral cortex.

Microiontophoretic administrations of morphine to cholino-excitable neurones in the cerebral cortex of decerebrate cats evoked a weak excitation which became more prominent upon repeated administrations of the alkaloid. This effect was not antagonized by naloxone. Iontophoresis of methylatropine prevented the excitation induced with acetylcholine and morphine, leaving that caused by glutamate relatively unaltered. Similar applications of morphine to neurones which were not excited by test applications of acetylcholine did not result in excitation but elicited mainly a depression of glutamate-evoked firing. It is suggested that the muscarinic effect of morphine in the cortex may be related to the excitation and convulsions, but not the analgesia, which occurs upon systemic administrations of the narcotic.

Acetylcholine↗