Lisuride in extrapyramidal disorders: a possible mechanism of action.
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Biomedical subjects
Publications and source records attributed to L Frattola.
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The authors studied the effects of lisuride hydrogen maleate (lisuride) on the hyperkinesias of 11 patients suffering from Huntington's chorea (HC). In all patients, acute injection of 150 micrograms of the drug induced a marked temporary improvement of the abnormal involuntary movements; the favourable drug-effect was more pronounced in the patients with a less severe degree of hyperkinesia. The antichoreic activity of the drug was prevented by pretreatment with haloperidol (2 mg) or sulpiride (400 mg), both injected intramuscularly 30 min before lisuride administration. The authors suggest the improvement of the motor disturbance induced in HC by lisuride may be explained on the basis of its preferential action on a subset of brain dopaminergic receptor.
The biochemical characteristics of the protein kinase (PK; adenosine triphosphate-protein phosphotransferase, EC 2.7.1.37) isozymes in subcellular preparations from normal human brain cortex and glioblastoma were investigated after chromatography on diethylaminoethyl cellulose, and the following results have been obtained. Two major isozyme forms, eluted by 50 and 200 mM phosphate buffer, are present in both cytosol and membrane-derived preparations from cerebral cortex. Furthermore, these isozyme forms have properties similar to those referred to as type I and type II cyclic adenosine 3':5'-monophosphate-dependent PK. In these chromatographic isozymes, cyclic adenosine 3';5'-monophosphate is more active in stimulating the basal PK enzyme than is cyclic guanosine 3':5'-monophosphate. In glioblastoma, the PK activity from cytosol and particulate preparations is resolved by diethylaminoethyl cellulose in four peaks. In cytosol, the major portion of the enzyme is eluted with a 300 mM buffer (about 50% of the total basal PK activity) and is cyclic nucleotide dependent. On the contrary, in glioblastoma particulate, the PK enzyme is mainly eluted at 50 and 100 mM buffer; neither of these isozymes is cyclic nucleotide dependent. As for cytosol, only the particulate isozyme eluted at 300 mM buffer is strongly activated by cyclic nucleotides. Finally, in both glioblastoma subcellular preparations, only a type II cyclic adenosine 3':5'-monophosphate-dependent PK is present.
Myopatic changes observed in muscle of rats after abdominal aorta ligation and/or serotonin injection have been regarded as a suitable model to explore the possibility that vasoactive treatments induce muscular damage similar to human myopathies. In the present study, we investigated the effect of serotonin administration to normal and aorta-ligated rats on cAMP-dependent protein-kinase (PK) and hydrolytic enzymes in skeletal muscle.
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In this study the effects of an acute injection of lisuride and apomorphine in 12 subjects affected by dystonic-dyskinetic syndromes of different aetiology are evaluated: 3 patients with spasmodic torticollis, 4 with tardive dyskinesia and 5 Parkinson patients suffering from "on-off" attacks with prominent dyskinesias during the mobile phase. In the last group drugs were administered during the "on" phase. In 11 out of 12 patients both lisuride and apomorphine induced a marked improvement of the abnormal involuntary movements. In Parkinson and torticollis patients both drugs also reduced the rigidity. In comparison to apomorphine, lisuride showed a more effective and long-lasting action. Only in one Parkinson patient did the drugs fail in showing any change.
Cerebral microvessels were separated and prepared from human brain cortex by albumin floatation and glass bead filtration. The binding of a specific beta-adrenergic antagonist, (125I) iodohydroxybenzylpindolol, to the microvessel preparation was characterized by high affinity, saturability, and stereospecificity. The presence of specific beta-adrenergic receptor sites in human cerebral microvessels supports the hypothesis of adrenergic regulation of the function of cerebral microvessels.
The properties and distribution of basal and cyclic nucleotide stimulated protein kinases have been studied in normal and diseased human muscles. In particulate fraction of muscles from neurogenic atrophy the PK activity is remarkably lower than in control tissues, whereas in the cytosol of the same tissues an increase of enzyme activity was observed. In Duchenne dystrophy the PK activities were slighly lower than in controls both in particulate and in soluble fractions. The authors suggest that the altered subcellular distribution found in neurogenic atrophy might be due to the loss of nerve trophic control.
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The observation of a patient suffering from a parkinsonian syndrome, almost entirely expressed on the right side, and "on-off" attacks with rotatory movement of the trunk, led us to consider that the rotational model of animals may be reproduced in man. The symptoms presented by our patient may reflect a predominant degeneration in the nigrostriatal pathway of the left side. We suggest that his torsion behavior is due to hypersensitivity phenomenon of the dopaminergic receptors on this side.
Cyclic nucleotide phosphodiesterase activity has been measured in muscle biopsies taken from healthy controls and from cancer patients. In both groups the muscles were clinically and morphologically normal. The phosphodiesterase activity was significantly increased in muscles from cancer patients using both cyclic AMP and cyclic GMP as substrate. These findings are in line with previous reports indicating that malignancy may interfere with metabolism of the host muscular tissues, and suggest the possibility that the observed biochemical changes might be an aspect of an early muscle neurogenic involvement.
Since the effects of cyclic nucleotides are mediated via protein kinases activation, we have studied the properties and regulation of these enzymes in cytosol and particulate fraction of normal cerebral tissues and of some human brain tumors. We found that distribution and activity of cyclic nucleotide-dependent protein kinases are regulated differently among various brain tumors and in comparison to normal gray and white matter. Pathological tissues show an higher cGMP-dependent protein kinase and this biochemical pattern is particularly evident in tumors with more pronounced malignancy. These data further confirm the hypothesis of a correlation between the increase of cGMP function and cellular growth and malignancy.
Sleep induction has been studied in humans after the administration of apomorphine, a direct stimulant of the central dopaminergic system. The drug induced sleep and vomiting in healthy volunteers while it had no significant effect on 10 Parkinsonism patients treated for a long period with L-dopa. Apomorphine given to a group of Parkinsonism patients not receiving any specific treatment, and with a lower degree of disease severity, induced vomiting and sleep with a pattern similar to that in healthy subjects. A relationship between the dopaminergic system and sleep induction is suggested.
Twenty patients suffering from transient attacks of ischaemia were studied. Seven received acetylsalicylic acid, six dipyridamole and seven a combination of the two drugs. No significant difference in platelet aggregation was shown in the acute phase between the three treatment groups using an adenosine diphosphate test method. Using Thrombofax platelet substitute, however, a significant difference was seen in all measures. On the seventh day following the ischaemic attack the Thrombofax values returned to normal but, in contrast, Platelet Factor 4 release was increased. Monthly testing of platelet activity during treatment shows that the combination of acetylsalicylic acid with dipyridamole was more effective in bringing about an early inhibition of Platelet Factor 4 release than either agent alone.
A case of thyrotoxicosis associated with neuropathy and encephalomyelitis is reported which gradually improved as regards the hyperthyroidism and the neurological deficit during treatment with Tapazole. The possible role of the nervous system of an excess of thyroxine or an autoimmune factor as a cause of the involvement is discussed.
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Guanylate cyclase activity has been studied in muscle of normal subjects and of patients suffering from muscular and neuromuscular diseases. In normal tissue a guanylate cyclase activity was found in both soluble and particulate fractions of homogenate. We found also that the kinetic analysis of the enzyme of soluble differed from that of particulate fraction. A decrease of guanylate cyclase activity in crude homogenate was observed in muscular dystrophies, in neuromuscular atrophies, and in inflammatory forms of muscle disease.