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G Spignoli

Publications and source records attributed to G Spignoli.

28 records · Page 2Linked to original sources
PubMed1986

Oxiracetam prevents electroshock-induced decrease in brain acetylcholine and amnesia.

In the rat, 1 min following electroshock (ECS) a 46 and 39% decrease in acetylcholine levels was found in the hippocampus and cerebral cortex, respectively. The decrease in the hippocampus was still statistically significant 30 min after ECS. The ECS applied 1 min after training also disrupted the performance of a passive avoidance conditioned response ('step down') tested 30 min later. Oxiracetam (100 and 300 mg/kg i.p.) administered 90 min before training prevented, in a dose-dependent manner, the decrease of acetylcholine in the cerebral cortex and hippocampus. Oxiracetam prevented the ECS disruption of the acquisition of a passive avoidance response. At the dose of 300 mg/kg the acetylcholine level 1 min after ECS was significantly higher than in the sham-treated rats. Piracetam at the same doses was inactive. These results support the hypothesis that oxiracetam may prevent the disruption of the conditioned response by acting on cortical and hippocampal cholinergic mechanisms.

Acetylcholine↗
PubMed1986

Effect of oxiracetam and piracetam on central cholinergic mechanisms and active-avoidance acquisition.

Oxiracetam at 100 and 300 mg/kg i.p. dose levels increased acetylcholine (ACh) utilization in the rat cerebral cortex and hippocampus. ACh utilization was assessed by measuring, with a gas chromatographic method, the decrease in ACh level after inhibiting its synthesis by 15 micrograms intracerebroventricularly (i.c.v.) injection of hemicholinium (HC-3). ACh steady state levels were not affected. Piracetam (300 mg/kg i.p.) also increased ACh utilization in the hippocampus. Repeated daily administration of oxiracetam 100 mg/kg i.p. caused a 31% increase in high-affinity choline uptake (HACU) in the hippocampus. A single administration of 300 mg/kg i.p. of oxiracetam and piracetam also increased HACU rate in the hippocampus. However, the effect of piracetam was over within 3 h, while 3 h after its administration oxiracetam still caused a 40% increase in HACU rate. Oxiracetam (100 mg/kg i.p.) significantly antagonized the impairment in the acquisition of an active-avoidance conditioned response (pole climbing) associated with the inhibition of ACh synthesis by HC-3. These results indicate that oxiracetam enhances the activity of the septohippocampal cholinergic pathways, and to a lesser extent, of the cortical cholinergic network.

Acetylcholine↗
PubMed1985

Phosphatidylserine increases acetylcholine release from cortical slices in aged rats.

Acetylcholine release was investigated in cortical slices superfused with choline-enriched Krebs solution containing physostigmine. Slices were prepared from 3 and 24 month old rats treated with either Tris buffer or sonicated suspensions of phosphatidylserine and phosphatidylcholine in Tris buffer. Slices were electrically stimulated at frequencies of 1, 2 and 5 Hz for 5 min periods preceded and followed by rest periods. ACh content of the superfusate was quantified by bioassay. In the 24 month old rats treated with Tris buffer, acetylcholine release, at all frequencies tested, was approximately 50% lower than that in the 3 month old rats. On the contrary, no significant decrease in ACh release was found in the 24 month old rats treated for 30 days with phosphatidylserine (15 mg/kg IP). The same treatment did not increase acetylcholine release in 3 month old rats. Acetylcholine release in 24 month old rats receiving a single administration of phosphatidylserine (15 mg/kg IP) or phosphatidylcholine (15 mg/kg IP) for 30 days was as low as in the 24 month old rats receiving the Tris buffer only. It is proposed that the chronic phosphatidylserine treatment may reduce the age-induced decrease in acetylcholine release by acting on the stimulus-secretion coupling mechanism.

Acetylcholine↗
PubMed1984

Biphasic effect of methylxanthines on acetylcholine release from electrically-stimulated brain slices.

The effect of caffeine and aminophylline on the release of acetylcholine (ACh) was investigated in slices of rat cortex perfused with Krebs solution at rest and during electrical stimulation at frequencies of 0.2, 1 and 5 Hz. Both methylxanthines added to the superfusing Krebs solution at a concentration of 50 microM enhanced ACh release. Conversely, at a concentration of 0.5 mM both caffeine and aminophylline decreased ACh release. Neither caffeine nor aminophylline affected the unstimulated ACh release. Dipyridamole 10 microM potentiated the inhibitory effect of adenosine 30 microM on ACh release and antagonized both the stimulatory and inhibitory effects of caffeine on ACh release. The inhibitory effect of caffeine was antagonized by cyclohexyladenosine (CHA) 0.5 microM and N-ethylcarboxamideadenosine (NECA) 5 microM. The results indicate that methylxanthines exert both stimulatory and inhibitory effects on ACh release by acting on adenosine receptors. Methylxanthines may enhance the electrically-evoked ACh release by antagonizing the effect of endogenous adenosine on inhibitory adenosine receptors. On the other hand the mechanism through which methylxanthines decrease ACh release remains obscure.

Acetylcholine↗
PubMedDate not supplied

A plaster combining diclofenac and heparin: microcirculatory evaluation in 2 models of high-perfusion microangiopathy.

A medicated plaster containing diclofenac epolamine (DHEP) and heparin has been recently proposed for the treatment of local trauma (ie, ankle sprains) accompanied by a clinically significant edema and/or hematoma formation, based on the combined antiinflammatory, hemorheologic, and antiedema properties of diclofenac and heparin. The aim of this study was therefore to compare the effects of a combined DHEP/heparin and DHEP alone in 2 clinical experimental models of microangiopathy, in order to provide a pharmacologic rationale for association of diclofenac and heparin. The microcirculation was evaluated by measuring cutaneous blood flow (laser Doppler) and transcutaneous oxygen and carbon dioxide pressures (TcPO(2) and TcPCO(2)) in 10 healthy volunteers before and after producing 2 microcirculatory models of microangiopathy: the models were based on reactive hyperemia (RH) and on local histamine injection, which both produce a significant increase in skin flux and alterations of TcPO(2) and TcPCO(2). The area of the study was the distal medial leg, treated with placebo, DHEP alone (Flector Tissugel), and DHEP/heparin (Flector Tissugel Heparin). The plasters were applied before producing the microcirculatory models to evaluate the efficacy of DHEP and DHEP/heparin in controlling and limiting vasodilatation and development of microangiopathy. A significant increase in cutaneous flux was obtained with both models. The application of DHEP partially limited the increase in flux and in TcPCO(2), as well as the decrease in TcPO(2) (which were considered signs of microangiopathy), but the combination DHEP/heparin was significantly more effective than DHEP alone. The inclusion of heparin in the plaster thus improved the control of the microcirculation achieved with diclofenac alone, when an experimental model of venous/arterial hyperemia and microangiopathy was used. In conclusion, DHEP in association with heparin modulates microcirculatory changes better than DHEP alone. It should be interesting to investigate the product in comparable clinical conditions in which it may be useful to act pharmacologically both on inflammation and microcirculatory disturbances that delay the recovery of patients.

Adult↗