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J J Legros

Publications and source records attributed to J J Legros.

At least 19 recordsLinked to original sources
PubMed1992

Oxytocin blocks the environmentally conditioned compensatory response present after tolerance to ethanol-induced hypothermia in mice.

The present study tested the hypothesis that the attenuation by oxytocin of tolerance to ethanol-induced hypothermia relies upon an impairment of the putative conditioning processes underlying environment-specific tolerance. According to the conditioning model of tolerance, such tolerance occurs because an opposite compensatory response conditioned to ethanol-paired cues attenuates ethanol's effects. Tolerance to ethanol-induced hypothermia was established to a particular environment over 4 days by injecting mice (daily) with oxytocin 2 h before ethanol, outside the colony room. As controls, other mice were injected similarly but following testing in the animal room. We found that oxytocin suppressed the conditioned compensatory response, revealed by injecting saline to every group in the tolerance-associated environment. These results suggest that oxytocin acted, at least partly, via an inhibition of the associative learning processes that facilitate tolerance development.

Animals↗
PubMed1992

Apomorphine stimulation of vasopressin- and oxytocin-neurophysins. Evidence for increased oxytocinergic and decreased vasopressinergic function in schizophrenics.

Apomorphine challenge tests (0.5 mg SC) were performed in 14 normal male volunteers and in 9 male schizophrenic inpatients, drug-free for at least 2 wk. In the normal volunteers, apomorphine induced an increase of serum growth hormone (GH) (maximum at 40 min), of vasopressin-neurophysin (hNpI) (maximum at 20 min), and oxytocin-neurophysin (hNpII) (maximum at 20 min). The release of neurophysins was independent of digestive side effects. In the schizophrenics, the GH level and release pattern were similar to those in the controls. The basal level of hNpI was reduced (t0: 0.42 +/- 0.1 ng/ml in the schizophrenics and 0.66 +/- 0.05 ng/ml in the controls, p < 0.02). In contrast, the basal level of hNpII was increased (3.34 +/- 0.04 ng/ml in the schizophrenics to 0.92 +/- 0.21 ng/ml in the controls, p = 0.001). The response to apomorphine was blunted, with no significant release of hNpI or of hNpII. Although the hNpII data are consistent with an increased dopaminergic tone, the psychopathological meaning of the increased basal oxytocinergic and decreased vasopressinergic functions remains to be defined.

Adult↗
PubMed1992

Neurohypophyseal peptides and psychopathology.

The study of neurohypophyseal peptides in various neuropsychiatric disorders is of interest because the hypothalamo-posterior pituitary axis is directly influenced by modifications of central neurotransmitter metabolism involved in behaviour control. Moreover, the main neurohypophyseal peptides, namely vasopressin and oxytocin, are themselves capable of modifying behaviour. In this paper the author discusses current understanding of the anatomy and physiology of the main central vasopressinergic and oxytocinergic pathways, followed by a description of the principal actions of exogenously administered vasopressin and oxytocin on human behaviour. Finally, modification of endogenous neurohypophyseal function encountered in different pathological states are described.

Amino Acid Sequence↗
PubMed1991

Colocalization of immunoreactive oxytocin, vasopressin and interleukin-1 in human thymic epithelial neuroendocrine cells.

Monoclonal antibodies to oxytocin (OT) and vasopressin (VP) revealed some positively staining stromal cells in the subcapsular cortex and in the medulla of the human thymus. We further demonstrated that these cells are a subset of epithelial endocrine cells and also contain immunoreactive interleukin-1 together with the neuropeptides. In addition, the thymic cells stained by monoclonal antibodies directed to the cyclic part of oxytocin or vasopressin also contained some immunoreactive neurophysins. These data support the concept of intrathymic synthesis of neurohypophyseal-like peptides fitting the hypothalamic model. However, we observed that, contrary to the situation in the brain, OT- and VP-like peptides colocalized in the same thymic cells. Furthermore, one monoclonal antibody, specific for the tail part of oxytocin, did not label thymic cells. Therefore, thymic neuropeptide(s) could be related to, but distinct from, authentic OT and VP. These observations suggest some molecular differences between hypothalamic and thymic oxytocin biosynthetic pathways which need to be further investigated.

Antibodies, Monoclonal↗
PubMed1990

Expression of preprotachykinin-A and neuropeptide-Y messenger RNA in the thymus.

The preprotachykinin-A gene, the common gene of mRNAs encoding both substance-P (SP) and neurokinin-A (NKA), was shown to be expressed in Sprague-Dawley rat thymus by detection of specific mRNA in gel-blot analyses. In situ hybridization revealed dispersed PPT-A-labeled cells in sections from rat thymus, with a concentration of grains over a subpopulation of cells in the thymic medulla. Also, neuropeptide-Y mRNA-expressing cells were found in the rat thymus, primarily in the thymic medulla. Rat thymic extracts contained SP-like immunoreactivity (SP-LI), and the major part of the immunoreactivity coeluted with authentic SP and SP sulfoxide standards. SP-LI was also detected in human thymus, which contained between 0.09-0.88 ng SP-LI/g wet wt. Evidence for translation of preprotachykinin-A mRNA in the rat thymus was obtained from the demonstration of NKA-LI in thymic cells with an epithelial-like cell morphology. Combined with previous observations on the immunoregulatory roles of tachykinin peptides and the existence of specific receptors on immunocompetent cells, the demonstration of intrathymic synthesis of NKA suggests a role for NKA-LI peptides in T-cell differentiation in the thymus.

Animals↗
PubMed1979

[Neurophysins].

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Diabetes Insipidus↗
PubMed1979

[Hereditary motor neuron disease: the proximal, adult, sex-linked form (or Kennedy disease). Clinical and neuroendocrinologic observations].

Clinical, electrophysiological, histological and neuroendocrinological findings in a peculiar form of progressive spinal and bulbar muscular atrophy affecting 4 members in two different families are reported. The clinical hallmarks, which characterize this entity among the group of degenerative motor neuron diseases are: sex-linked recessive inheritance; onset in the third decade; slow progression; involvement of facial and bulbar muscles in addition to wasting of the proximal and, in some cases, the distal musculature; asymmetry of clinical signs; consistent and abundant fasciculations predominantly in the peri-oral muscles; intention tremor and a well-developed gynaecomastia, which is the first clinical sign. Electrophysiological and histological findings confirm the neurogenic origin of the muscular atrophy; in addition, muscle biopsy shows "myopathic-like" changes in one case and serum muscle enzyme levels are elevated in all neurologically affected patients. It is believed that the clinical entity corresponds to the rare type III proximal hereditary motor neuropathy (or "Kennedy's disease"), of which 25 published cases are reviewed. Neuroendocrinological data in two patients demonstrate an androgenic insufficiency of hypothalamo-hypophyseal origin and high levels of circulating oestrogens, which probably have induced gynaecomastia. Dynamic neuroendocrinological tests suggest that lesions of certain hypothalamic nuclei may exist, which should be looked for in the forthcoming anatomical studies.

Adult↗
PubMed1979

[Systematic evaluation of 8 arginine vasopressin and neurophysins plasma levels in 10 patients with oat cells carcinoma of the lung (author's transl)].

Plasma AVP level, neurophysins and osmolality have been measured in 10 patients with oat cell carcinoma of the lung but without any biological signs of syndrome of inappropriate secretion of ADH (SIADH), before and 15 mn after an intravenous injection of Ethanol. No statistically significant difference was noted in the AVP, neurophysins and osmolality values between 10 patients with asymptomatic oat cell carcinoma and control population (10 normal volunteers, 12 patients with non neoplasic lung pathology and 10 patients with different lung carcinoma). We concluded that AVP and neurophysins cannot be considered as a good tumoral marker in the detection of oat cell carcinoma of the lung.

Arginine Vasopressin↗