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Biomedical subjects

F Aporti

Publications and source records attributed to F Aporti.

At least 19 recordsLinked to original sources
PubMed1986

The action of AD6 on experimental arrhythmias and on action potentials of cardiac fibers.

AD6 is a coumarinic derivative which increases both coronary blood flow and prostacyclin production, while it decreases platelet responsiveness. We tested its action on experimental cardiac arrhythmias. AD6 (2.5-10 mg/kg) was able to antagonize the arrhythmogenic action of aconitine in rats and of adrenaline in cats. AD6 action was also tested in vitro. The drug (20-50 microM) prolonged the functional refractory period of guinea-pig atrial and ventricular muscle and lengthened the refractory period shortened by hypoxia. Intracellular electrophysiological experiments showed that AD6 prolongs action potential duration (APD) of guinea-pig atrial myocardium, sino-atrial node and cat Purkinje fibers. The results obtained in vitro may explain the effect on experimental arrhythmias, therefore suggesting a protective action on cardiac rhythm disturbances.

Aconitine↗
PubMed1985

Experimental models of aging and quinolinic acid.

The normal aging process results in many functional deficits in which the central nervous system (CNS) plays a primary role. However, the study of brain aging involves numerous difficulties, including not only the complex anatomical and functional organization of the brain itself, but also because the length of the experiments themselves and experimental costs are often crucial limitations. This highlights an ever increasing need for the development of alternative model systems capable of mimicking at least to some degree the main alterations observed during the normal aging process. A comparative study of electrophysiological and behavioural features in aged rats and in young rats following chronic administration of a naturally occurring brain metabolite, quinolinic acid (QUIN), recently demonstrated to increase in the cerebral cortex of rats as a function of age, is reported. In rats there occurs an age-dependent increase in the number of animals displaying spontaneous asymptomatic spike-wave discharges, associated with impaired performance in the passive avoidance test. Chronic oral administration of QUIN to young rats also results in cortical spiking activity, without any detectable neuronal cell damage at cortical or hippocampal levels, associated with behavioural deficits similar to those observed in old rats. The utilization of young, QUIN-treated animals may thus perhaps offer an alternative model system for the comprehension of the mechanisms involved in some age-related functional impairments.

Aging↗
PubMed1985

Serine phospholipids and aging brain.

For many years phospholipids have been studied mainly for their possible use as membrane models or cell-like carriers. Recently, on the basis of the new knowledge on the phospholipid membrane structure and function, a novel interest has arisen on the pharmacological properties of these compounds particularly at cerebral level. In this context particular attention has been devoted to phosphatidylserine (BC-PS), an anionic phospholipid extracted and purified from bovine brain, which in young animals has been shown to modify a number of brain electrophysiological and biochemical parameters.

Aging↗
PubMed1984

The functional recovery of damaged brain: the effect of GM1 monosialoganglioside.

In the present study the topology and the biochemical mechanisms underlying the functional recovery of the dopaminergic nigrostriatal system is further analyzed. Rats with unilateral hemitransection were treated with 30 mg/kg GM1 monosialoganglioside or with its internal ester derivative for different periods of time. GM1 enhances 3H-dopamine uptake in striatal synaptosomes of the lesioned side, and the enhancement of dopamine uptake precedes that of striatal tyrosine hydroxylase activity. The above biochemical effects are accompanied by changes in behavioral- and electrophysiological-related parameters. The effect of GM1 on striatal tyrosine hydroxylase of the lesioned side disappears when the ascending dopaminergic fibers are extensively lesioned. This suggests that the source of regrowing dopaminergic nerve terminals in the striatum of partially lesioned rats resides mainly in the intact axons remaining in the ipsilateral side. When GM1 is injected into partially lesioned rats kept in darkness, no effect on tyrosine hydroxylase activity is observed. This indicates that the mechanism through which GM1 acts involves a normal light-dark cycle.

Animals↗
PubMed1984

Ganglioside treatment of genetic and alloxan-induced diabetic neuropathy.

Peripheral neuropathy is a common complication of diabetes. Using the mutant diabetic mouse C57BL/ks (db/db) and alloxan-treated rats, 30 days after intoxication, we investigated development and treatment with gangliosides of such a disease. The db/db mouse develops a neuropathy characterized by a loss in conduction velocity shown as early as 80-90 days after birth and maintained throughout life. At later stages (5-6 months of age) there is a drop in slow transport and myelin particle density. These changes are correlated by a lack of response to insulin treatment, which, prior to this stage, is capable of improving nerve conduction velocity (NCV). On the other hand gangliosides became effective, improving NCV, myelin particle density and sensory perception (auditory deficit) at 5 months of age in the db/db mouse. We presume that this differential neuronal response to insulin and gangliosides indicates a change of the neuropathy from a metabolic stage to neuronal. Alloxan induced diabetic neuropathy is treatable with gangliosides even 30 days after intoxication.

Acetylcholinesterase↗
PubMed1984

Effects of phosphatidylserine on avoidance relearning in rats (preliminary observations).

During six learning sessions in a shuttle-box avoidance situation, male Sprague-Dawley rats show two kinds of learning efficiency which allow for dividing them in the subgroups of high-responding (HR) and low-responding (LR) animals. The effect of phosphatidylserine, a pharmacologically active phospholipid obtained from bovine brain, has been studied on the relearning phase of these two populations of rats. Chronic administration of phosphatidylserine (15 mg/kg i.p. for 30 days) significantly increased the avoidance performances of LR animals, without changing those of HR rats. The results obtained suggest that the different behavioral response to the phosphatidylserine treatment may depend on the pre-drug baseline of avoidance learning capability and on the effect that the drug exerts on some brain neurotransmitter metabolism.

Animals↗
PubMed1981

Changes in rabbit brain cytosolic and membrane-bound gangliosides during prenatal life.

The present study deals with the developmental profile of cytosolic and membrane-bound gangliosides in rabbit whole brain from the 21st day of pregnancy, the time at which brain could be macroscopically recognized and handled, till birth. In this period of prenatal life the content of membrane-bound gangliosides showed a 2.5-fold increase, referred to fresh and dry brain weight and to membrane-bound protein; the content of cytosolic gangliosides reached a maximum at 21-22 days of pregnancy, and then underwent to birth a threefold diminution. The qualitative pattern of membrane-bound gangliosides, in the same period of life, was characterized by an increase of GD1a and GM1 (more marked for GD1a), a decrease of GT1a, GT1b and GQ1b, and a constant level of GD3 and GD1b. At 21 days of pregnancy the most abundant gangliosides were GT1b and GQ1b, followed by GD1a and GD1b; at birth it was GD1a, followed by GT1b, GD1b and GM1. The qualitative pattern of cytosolic gangliosides closely resembled, during the entire period of prenatal life examined, that of membrane-bound gangliosides.

Animals↗
PubMed1976

Effects of brain gangliosides on functional recovery in experimental regeneration and reinnervation.

The effect of brain cortex gangliosides has been tested in two different experimental models of peripheral sympathetic regeneration and reinnervation: a) the preganglionic trunks of the cervical sympathetic nerve were joined in an end-to-end anastomosis after severing the preganglionic trunk, caudally to the superior cervical ganglion; this reinnervation is mainly of cholinergic type. b) the postganglionic trunks of the superior cervical ganglion were joined in an end-to-end anastomosis after severing the postganglionic trunk; this reinnervation is mainly of adrenergic type. Functional recovery following the regeneration and reinnervation has been evaluated by measuring tha contraction of the nictitating membrane, evoked by electrical stimulation of the sympathetic trunk caudally to the point of anastomosis. Some of the operated animals were daily treated with 50mg/kg i.p. of brain cortex gangliosides during the entire post-operative period. Forty-five, sixty days after the operation we observed in the treated animals of both experimental sets a relevant increase in the functional recovery (between 30 and 100%) compared to the operated but untreated controls. In the case of postganglionic anastomosis the physio-pharmacological studies were substantiated by the histochemical fluorescence observations of the distributions of catecholamines in the smooth muscle of the nictitating membranes. These results strongly suggest that the treatment with gangliosides greatly influences the regeneration and reinnervation process of both cholinergic and adrenergic nerve fibers.

Animals↗
PubMedDate not supplied

Treatment of denervated muscle by gangliosides.

Short-duration cooling of the nerve to the extensor digitorum longus muscle of the rat in vivo induced partially reversible denervation of the muscle and atrophy in the type 2 muscle fibers. Increases in cyclic adenosine monophosphate, cyclic guanosine monophosphate phosphodiesterase, adenylate cyclase, and guanylate cyclase were observed in the denervated muscle. Treatment with gangliosides of the bovine brain cortex seemed to improve the excitability of the surviving motor units and to encourage recovery of neuromuscular trophic control, but it did not affect the nerve conduction velocity or the contractile properties of the denervated muscle.

Animals↗