Effect of sparteine on status epilepticus induced in rats by pentylenetetrazole, pilocarpine and kainic acid

Lupin (Lupinus albus L.) Seeds: Balancing the Good and the Bad and Addressing Future Challenges

Lupinus albus L. (lupine) is a legume whose grain/seed has gained increasing interest. Its recognized nutritional properties, namely a high content of protein, dietary fiber and its low fat content, make lupine a suitable alternative not only for animal protein, but also as a substitute for more processed and less balanced flours from a nutritional point of view, used in the preparation of bread, cakes and cookies, among others. In addition, its nutritional and bioactive compounds have potential benefits for human health in the prevention and treatment of some diseases. However, the existence of some anti-nutritional compounds and contaminants reveal some concern, requiring effective methods for their detection and eventual removal. This review intends to address the potential of lupine (L. albus) in food and human health and to balance the pros and cons. Nutritional and anti-nutritional components of L. albus seeds and possible contaminants of lupine seeds are examined. The potential health benefits of lupine (seeds), including energy metabolism, cardiovascular diseases, hypertension, glucose and insulin metabolism, bower function and anticonvulsant action, are discussed based on scientific evidence (both clinical trials and studies performed with animal models).

The anticonvulsant effect of sparteine on pentylenetetrazole-induced seizures in rats: a behavioral, electroencephalographic, morphological and molecular study

Abnormal synchronous activity in neurons generates epileptic seizures. Antiepileptic drugs (AEDs) are effective in 70% of patients, but this percentage is drastically lower in developing countries. Sparteine is a quinolizidine alkaloid synthesized from most Lupine species and has a probable anticonvulsive effect. For this reason, the objective of the present work was to study the anticonvulsant effect of sparteine using a dose-effect curve and to determine its effectiveness against seizures using behavioral, electroencephalographic, morphological and molecular data. Wistar rats were grouped into control [saline solution (0.9%), pentylenetetrazole (90 mg/kg), and sparteine (13, 20 and 30 mg/kg), intraperitoneal (i.p.)] and experimental (sparteine + pentylenetetrazole) groups. The rats were implanted with surface electrodes to register electrical activity, and convulsive behavior was evaluated according to Velisek's scale. The rats were perfused to obtain brain slices for cresyl violet staining and cellular density quantification as well as for immunohistochemistry for NeuN and GFAP. Other animals were used to determine the hippocampal mRNA expression of the M2 and M4 acetylcholine receptors by qPCR. Sparteine exhibited a better anticonvulsant effect at a dose of 30 mg/kg (i.p.) than at the other doses used. This anticonvulsant effect was characterized by a decrease in the severity of convulsive behavior, 100% survival, an inhibitory effect on epileptiform activity 75 min after pentylenetetrazole administration, and the conservation of the cellular layers of CA1, CA3 and the dentate gyrus (DG); however, astrogliosis was observed after 30 mg/kg sparteine treatment. In addition, sparteine treatment increased the mRNA expression of the M4 receptor three hours after administration. According to our findings, the effective dose of sparteine as an anticonvulsant agent by i.p. injection is 30 mg/kg. The astrogliosis that was observed after sparteine administration may be a compensatory mechanism to diminish excitability and maintain neuronal homeostasis, possibly through redistributing potassium and glutamate. The increase in the mRNA expression of the M4 receptor may suggest the participation of the M4 receptor in the anticonvulsive effect of sparteine, as the activation of this receptor may inhibit acetylcholine release and facilitate the subsequent release of GABA. However, the precise mechanisms by which sparteine produces these effects are not known, and therefore, further experiments are necessary.

Hsp90β inhibitors prevent GLT-1 degradation but have no beneficial efficacy on absence epilepsy

The loss of glutamate transporter-1 (GLT-1) is associated with temporal lobe epilepsy (TLE). A recent study reported that Hsp90β interacted with GLT-1 and recruited it to 20S proteasome for degradation. Therefore, inhibiting Hsp90β may be a new strategy for treating epilepsy. So far, no studies have shown whether the inhibition of Hsp90β had therapeutic effects on absence epilepsy. Using a model of absence epilepsy, we demonstrated that 17-allylamino-17-demethoxygeldanamycin (17AAG) and Ganetespib (STA9090) had no therapeutic effect. Although this is a negative result, it also has a meaningful exploration value for whether Hsp90 inhibitors have therapeutic effects on other epilepsy types.

(+)-Dehydrofukinone modulates membrane potential and delays seizure onset by GABAa receptor-mediated mechanism in mice

(+)-Dehydrofukinone (DHF), isolated from Nectandra grandiflora (Lauraceae) essential oil, induces sedation and anesthesia by modulation of GABAa receptors. However, no study has addressed whether DHF modulates other cellular events involved in the control of cellular excitability, such as seizure behavior. Therefore, the aim of the present study was to investigate the effect of DHF on cellular excitability and seizure behavior in mice. For this purpose, we used isolated nerve terminals (synaptosomes) to examine the effect of DHF on the plasma membrane potential, the involvement of GABAa receptors and the downstream activation of Ca²⁺ mobilization. Finally, we performed an in vivo assay in order to verify whether DHF could impact on seizures induced by pentylenetetrazole (PTZ) in mice. The results showed that DHF induced a GABA-dependent sustained hyperpolarization, sensitive to flumazenil and absent in low-[Cl^-] medium. Additionally, (1-100μM) DHF decreased KCl-evoked calcium mobilization over time in a concentration-dependent manner and this effect was prevented by flumazenil. DHF increased the latency to myoclonic jerks (10mg/kg), delayed the onset of generalized tonic-clonic seizures (10, 30 and 100mg/kg), and these effects were also blocked by the pretreatment with flumazenil. Our data indicate that DHF has anticonvulsant properties and the molecular target underlying this effect is likely to be the facilitation of GABAergic neuronal inhibition. The present study highlights the therapeutic potential of the natural compound DHF as a suppressor of neuronal excitability.

Behavioral and genotoxic evaluation of rosmarinic and caffeic acid in acute seizure models induced by pentylenetetrazole and pilocarpine in mice

The goal of this study was to investigate the effects of rosmarinic acid (RA) and caffeic acid (CA) in the acute pentylenetetrazole (PTZ) and pilocarpine (PIL) seizure models. We also evaluated the effect of RA and CA on the diazepam (DZP)-induced sleeping time test and its possible neuroprotective effect against the genotoxic damage induced by PTZ and PIL. Mice were treated intraperitoneally (i.p.) with saline, RA (2 or 4 mg/kg), or CA (4 or 8 mg/kg) alone or associated to low-dose DZP. After, mice received a single dose of PTZ (88 mg/kg) or PIL (250 mg/kg) and were monitored for the percentage of seizures and the latency to first seizure (LFS) >3 s. Vigabatrin and DZP were used as positive controls. In the DZP-induced sleeping time test, mice were treated with RA and CA and 30 min after receiving DZP (25 mg/kg, i.p.). The alkaline comet assay was performed after acute seizure tests to evaluate the antigenotoxic profiles of RA and CA. The doses of RA and CA tested alone did not reduce the occurrence of seizures induced by PTZ or PIL. The association of 4 mg/kg RA + low-dose DZP was shown to increase LFS in the PTZ model, compared to the group that received only the DZP. In the DZP-induced sleeping time test, the latency to sleep was reduced by 4 mg/kg RA and 8 mg/kg CA. The PTZ-induced genotoxic damage was not prevented by RA or CA, but the PIL-induced genotoxic damage was decreased by pretreatment with 4 mg/kg RA (in cortex) and 4 mg/kg CA (in hippocampus). In conclusion, RA and CA presented neuroprotective effect against PIL-induced genotoxic damage and reduced the latency to DZP-induced sleep. Of the rosmarinic acid, 4 mg/kg enhanced the DZP effect in the increase of latency to clonic PTZ-induced seizures.

Sparteine as an anticonvulsant drug: Evidence and possible mechanism of action

Sparteine is a quinolizidine alkaloid extracted from Lupinus that has numerous pharmacological properties both in humans and animal models. In the central nervous system, sparteine reduces locomotor activity, has light analgesic effects, also has no effects on short-term memory or spatial learning and does not induce changes in behavior or electroencephalographic (EEG) activity. However, the anticonvulsant profile of sparteine is not fully characterized in experimental animals and there are no data in humans. Therefore, the present review focuses on the experimental evidence supporting the anticonvulsant action of sparteine in models of acute seizures and status epilepticus (SE), as well as its possible mechanisms of action. The evidence that supports the anticonvulsant effect of (-)-Sparteine sulfate includes the inhibition of seizures induced by maximal electro-stimulation, a delay in the onset of convulsive behavior and the prolongation of survival time in mice treated with pentylenetetrazole (PTZ). Additionally, sparteine delays the onset of convulsive behavior and decreases the severity and mortality of rats treated with PTZ and pilocarpine. Sparteine decreases amplitude and frequency or blocks the epileptiform activity induced by PTZ, pilocarpine and kainic acid. Sparteine may decrease hyperexcitability through the activation of the M2 and M4 subtypes of mAChRs, which is a probable mechanism of action that together with its systemic effects may favor its anticonvulsant effects against seizures and SE.