Biomedical subjects
Publications and source records attributed to M Roche.
S-Adenosyl-L-homocysteine (SAH) decreases the epileptiform discharges induced by hippocampic stimulation. SAH reduces the pentetrazol convulsions, does not modify picrotoxine convulsions, and increases strychnine toxicity. These effects are not linked to gamma-aminobutyric acid metabolism perturbation or to the concentration of some amino acids known for their action in synaptic transmission.
S-Adenosylhomocysteine (10(-7)-10(-5) M) activated norepinephrine (NE) and serotonin (5HT) in vitro uptake in synaptosomal preparations from rat brain, but did not affect dopamine (DA) uptake. When administered to rats (7 mg/kg i.p.), it has the same effect on in vitro NE and 5HT uptake. It did not affect NE and 5HT release.
S-adenosylmethionine (0,1 mg/kg/ip) decreases in vivo, norepinephrine (NE) synthesis and does not affect 5-hydroxytryptamine (5 HT) synthesis in the Rat brain. S-adenosylhomocysteine (7 mg/kg/ip) increases NE synthesis and decreases 5 HT synthesis. Neither nucleoside affects dopamine synthesis.
The myocardial effects of the lactonic deoxybenzoin glucoside, AP 10, an ATPases and cyclic AMP phosphodiesterases inhibitor, were investigated in vitro and in vivo. AP 10 showed marked positive inotropic effects on spontaneously beating frog and mammal isolated hearts. This drug induced a substantial increase in cyclic AMP atrial level comparable to that observed with papaverine in the rat. Its inotropic effects on stimulated rat left atria were moderate and suppressed by reserpine pretreatment, in contrast with papaverine inotropic effects which were not significantly modified. As papaverine (10(-5) M), AP 10 (10(-4) M) shifted to the left the atrial dose-response curve for isoproterenol. The positive inotropic effects of AP 10 were more pronounced at low calcium concentrations. Furthermore, AP 10 prolonged the time course of tension decline in stimulated rat left atria exposed to Ca++ free medium. AP 10 (1 mg/kg) did not induce any in vivo hemodynamic disturbance in both anaesthetized and conscious dogs and significantly improved ventricular automaticity in anaesthetized dogs (0.5 mg/kg). This drug was also compared to quinidine in two in vivo experimental arrhythmias. AP 10 was more effective than quinidine in preventing ouabain-induced arrhythmias in conscious rabbits and electrically-induced atrial fibrillation in conscious dogs. Despite its ATPases inhibiting properties and some structural similarities with cardiac glycosides, AP 10 did not show a typical "digitalis-like" pharmacological profile. It exhibited some of the myocardial features which characterize phosphodiesterase inhibitors as caffeine, papaverine or Ro 7-2956. An interesting particularity of AP 10 action was its capacity to prevent experimental arrhythmias.
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S-Adenosylhomocysteine (SAH) (0.1 to 30 mg/kg/i.p.) increased 3H-norepinephrine synthesis from 3H-tyrosine in the rat brain stem and mid brain, but did not alter its tissular level. It decreased both the serotonin level and the formation of 3H-serotonin from 3H-tryptophan and increased the formation of 3H-5hydroxyindolacetic acid. Its effects began 1 hr after administration and was still present 6 hr later. It did not alter dopamine metabolism. A correlation between the hynotic effect of SAH and the modification of the metabolism of cerebral monoamines was pointed out.
Chickens were chronically fitted with a duodenal cannula and pairs of electrodes implanted in the wall of the muscular stomach, duodenum and ileum. Smooth muscle electrical activity was recorded in both fed and fasted conditions under a 12--12 h dark-light schedule. Two major patterns of activity were identified. The first consisted of spike bursts that propagated rapidly either aborally from the stomach or orally from the ileum. Aborad-propagated spike bursts were most frequent during the daytime; this circadian variation was abolished by vagotomy, which also increased the frequency of orad-propagated spike bursts. The second pattern was characterized by periods of repetitive spike bursts lasting 3--10 min and spreading aborally at a slower rate. In the fasted chicken, the daily frequency was increased and the period of repetitive spike bursts resembled the prolonged bursts of spike potentials recorded in the feline small intestine. The results suggest that the propulsion of digesta might depend on the ratio of spike bursts moving aborally from the stomach to those moving orally from the ileum. Both factors were influenced by the level of stomach activity.
Electrical activity was recorded in conscious hens from chronically implanted electrodes in the smooth muscle layers of the oviduct. Transport of the egg through the magnum resulted from an inhibition of the electrical activity in the oviduct cranial to the egg and an increased spiking activity caudally. During an ovulatory cycle the progression of the egg was related to four different patterns of the uterine motility: within a sequence, the ovulatory cycles varied according to the duration of Phases 3 and 4.
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Nervous and hormonal controls of the gut system were studied in 42 hens using electromyography with transparietal electrodes. The results were analysed in relation with various biochemical parameters. The hormonal changes which occurred during sexual maturation and the ovulatory cycle induced directly the circadian organization of the motility of the gizzard and indirectly the motility of the intestinal tract. This resulted from variable metabolic requirements, the calcium being the most important element. An antagonism between gizzard and intestine motility was demonstrated. The pharmacological study confirmed the excitatory effect of the cholinergic system. For the adrenergic system, alpha receptors were predominant on the gizzard and beta receptors on the intestinal tract, especially in the distal part.
A patient with typical Landry-Guillain-Barré-Strohl syndrome (LG-BS) developed bilateral optic neuritis. Laboratory studies showed hypersensitivity to both central and peripheral nervous tissue myelin. The occurrence of optic neuritis is presumably due to autohypersensitivity to central nervous tissue myelin. The initial lesions of the LG-BS syndrome in the peripheral nerves might have liberated sequestered antigens that cross-reacted with central nervous system myelin.
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Two cases of anaphylactic shock during anaesthesia are presented, in which the etiology is confirmed by the lymphoblastic transformation test. In one case, the responsability was due to Pentothal, in the other to the combination of Pentothal-succinylcholine.
The motility and the pharmacological reactivity of the uterine tract of mammals are linked with the ovarian cycle and the gestation. In the birds, the study of general scheme of the hormonal mechanism and the uterine motility involued in the ovulation, the egg formation and the uterine dilatation can be used as an experimental model of the mammalian gestation.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.