Evaluation of Maternal Reproductive Outcomes and Biochemical Analysis from Wistar Audiogenic Rats (WAR) and Repercussions in Their Offspring.

The objective of the present study was to evaluate maternal reproductive performance, body weight, and frequency of external and internal anomalies of newborns of Wistar Audiogenic Rat (WAR) females as compared with Wistar rats. The adult WAR and Wistar rats were mated within their respective strains. After confirming the pregnancy, the body weights were weekly evaluated. On day 21 of pregnancy, the female rats were anesthetized and sacrificed to evaluate the maternal reproductive outcomes and biochemical profile, newborn weight, and external and internal anomalies. The WAR strain gained less weight during the pregnancy and presented hyperproteinemia, hypertriglyceridemia, and embryonic losses concerning Wistar rats, suggesting an inadequate intrauterine condition for embryonic development and fetal viability. WAR also presented a higher percentage of newborns classified as small for gestational age related to intrauterine growth restriction, which was confirmed by the lower number of ossification centers. There was a higher percentage of skeletal anomalies compared with fetuses of the Wistar dams, confirming their greater susceptibility during the formation and development of their skeletal system. Thus, the WAR presents physiological alterations compromising the viability of their embryos and fetuses, leading to impaired development of the newborns.

[Gender differences in the pool of free amino acid neurotransmitters in Krushinsky-Molodkina rats]. / Polovye otlichiia pula svobodnykh aminokislot-neiromediatorov u krys Krushinskogo-Molodkinoi.

The study of the role of neurotransmitter systems in the pathogenesis of epilepsy is one of the priorities of epileptology. New data on the functions of free neurotransmitter-like amino acid in the central nervous system are of the greatest importance and determine the prospects for the development of novel effective anticonvulsants. It is widely believed in clinical medicine that epilepsy has distinct gender characteristics. The aim of this study was to investigate the gender peculiarities in the content of neurotransmitter amino acids in the brain of Krushinsky-Molodkina (KM) rats, which were used as model organisms for the study of genetically induced audiogenic epilepsy. The content of Asp, Glu, GABA, Gly, and Tau of the medulla oblongata, hippocampus and cerebral cortex were determined using high-performance liquid chromatography (HPLC) in intact KM rats, KM rats exposed to a series of epileptiform seizures, and Wistar rats (control group). Both the Wistar and KM rats had gender distinctions in the distribution of free amino acids among the investigated brain parts. The audiogenic epilepsy was characterized by smoothing gender differences as well as differences between the concentrations of free amino acids in the cortex and medulla oblongata, specific for Wistar rats. The changes observed in male rats after the set of seizures included the increase in GABA concentration and a decrease in the Gly level in all investigated brain parts, as well as the decrease of the Tau content in the cortex and hippocampus. At the same time, the Glu content in cortex increased, while the Asp level decreased. After 6 days of audiogenic stimulations the female KM rats demonstrated the increase in the Glu level in all investigated brain parts, the increase in Gly and Asp levels in hippocampus, and no changes in the GABA content. Thus, after the set of epileptiform seizures the KM rats achieved a new steady state of the studied amino acids pool, which differed in males and females. In this case, gender differences significantly changed after the seizures.

Pharmacokinetic-pharmacodynamic influence of N-palmitoylethanolamine, arachidonyl-2'-chloroethylamide and WIN 55,212-2 on the anticonvulsant activity of antiepileptic drugs against audiogenic seizures in DBA/2 mice.

We evaluated the effects of ACEA (selective cannabinoid (CB)1 receptor agonist), WIN 55,212-2 mesylate (WIN; non-selective CB1 and CB2 receptor agonist) and N-palmitoylethanolamine (PEA; an endogenous fatty acid of ethanolamide) in DBA/2 mice, a genetic model of reflex audiogenic epilepsy. PEA, ACEA or WIN intraperitoneal (i.p.) administration decreased the severity of tonic-clonic seizures. We also studied the effects of PEA, WIN or ACEA after co-administration with NIDA-41020 (CB1 receptor antagonist) or GW6471 (PPAR-α antagonist) and compared the effects of WIN, ACEA and PEA in order to clarify their mechanisms of action. PEA has anticonvulsant features in DBA/2 mice mainly through PPAR-α and likely indirectly on CB1 receptors, whereas ACEA and WIN act through CB1 receptors. The co-administration of ineffective doses of ACEA, PEA and WIN with some antiepileptic drugs (AEDs) was examined in order to identify potential pharmacological interactions in DBA/2 mice. We found that PEA, ACEA and WIN co-administration potentiated the efficacy of carbamazepine, diazepam, felbamate, gabapentin, phenobarbital, topiramate and valproate and PEA only also that of oxcarbazepine and lamotrigine whereas, their co-administration with levetiracetam and phenytoin did not have effects. PEA, ACEA or WIN administration did not significantly influence the total plasma and brain levels of AEDs; therefore, it can be concluded that the observed potentiation was only of pharmacodynamic nature. In conclusion, PEA, ACEA and WIN show anticonvulsant effects in DBA/2 mice and potentiate the effects several AEDs suggesting a possible therapeutic relevance of these drugs and their mechanisms of action.

Dose-dependent suppression of human photoparoxysmal response with the competitive AMPA/kainate receptor antagonist BGG492: Clear PK/PD relationship.

OBJECTIVE: Examine the efficacy of a competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate glutamate receptor antagonist, selurampanel (BGG492), in the human photostimulation model. METHODS: Patients with epilepsy and a generalized epileptiform electroencephalography response to intermittent photic stimulation (photoparoxysmal response or PPR; diagnosed ≥ 6 months prior to initial study dosing) were enrolled in a phase II, multicenter, single-blind, within-subject, placebo-controlled proof-of-concept (PoC) study. PPR was used as a biomarker to assess the efficacy and safety of BGG492 in three cohorts (cohorts I-III received BGG492 50, 100, and 15 mg, respectively). Primary endpoints were to evaluate the efficacy of single oral BGG492 doses in abolishment of PPR or a relevant reduction of the standardized photoparoxysmal response (SPR), and to evaluate time of onset and duration of response. Secondary endpoints were to evaluate maximal SPR reduction, determine the pharmacokinetic profile of BGG492, explore the pharmacokinetic/pharmacodynamic relationship, and evaluate the safety and tolerability of BGG492. RESULTS: Ten patients were enrolled, with three participating twice, that is, in two cohorts (n = 13). Treatment with BGG492 resulted in abolition of PPR in seven of 13 patients in a dose-dependent manner: three, three, and one patient in cohorts I-III, respectively. All patients showed treatment-related reductions of SPR range of at least three steps in at least one eye condition (eye closure, eyes closed, or eyes open). Generally, onset of the suppressive effect appeared to be within 1-2 h post-BGG492 dose and continued in three patients at the 50- and 100-mg doses for 29-33 h. Most common adverse events across the BGG492-treated groups were headache and nasopharyngitis (three patients each), followed by dizziness, fatigue, and diarrhea (two patients each). SIGNIFICANCE: The dose-dependent positive effect of BGG492 on the PPR and SPR in patients with photosensitive epilepsy in this proof-of-concept study supports further investigation of AMPA receptor antagonists in large-scale phase III trials.

[THE INVESTIGATION OF VASOPRESSIN SECRETION IN NORMAL CONDITION AND DURING SEIZURE ONSET IN KRUSHINSKY-MOLODKINA RATS].

The aim of our study was to analyze vasopressin secretion rate from hypothalamic neurons in Krushinsky-Molodkina (KM) rats prone to audiogenic epilepsy in control and during audiogenic seizures. We evaluated vasopressin content in blood serum and neurophysin II amount in the neurohypophysis in KM rats as well as in Wistar rats. Obtained data demonstrated decreasing of vasopressin in the blood and at the same time increasing of neurophysin II content in the neurohy- pophysis of KM rats that revealed an inhibition of vasopressin release into blood circuit. The analysis of vasopressin content in blood on the different stages of audiogenic seizure showed significant increasing of vasopressin at clonustonus. Thus, we obtained first demonstration that in KM rats prone to audiogenic seizures vasopressin secretion rate is decreased in comparison to Wistar rats. Significantly upregulated vasopressin in blood at cloniconic stages reveals a participation of vasopressinergic neurosecretory system in the expression of audiogenic seizures.

No effects of the gonadal hormones on photoparoxysmal EEG responses in idiopathic generalised epilepsy.

PURPOSE: It is accepted that the estradiol hormone is proconvulsant and progesterone is anti-convulsant. In this study the effects of gonadal hormones on photoparoxysmal responses on EEG in idiopathic generalised epilepsy were researched. METHOD: Twenty-two women with photosensitive idiopathic generalised epilepsy having regular menstrual cycles were recruited into the study. Patients presenting photoparoxysmal responses were selected from routine EEG recordings. Blood samples were taken on day 14 (E) and 25 (P) of the menstrual cycle to confirm E and P peaks. An EEG recording was performed for each patient on E and P days. RESULT: No statistically significant differences were monitored with respect to frequency, duration of the photoparoxysmal responses on E and P peaks days (p>0.05). COMMENT: In this study no correlation could be demonstrated among menstrual cycle and photoparoxysmal responses.

Epilepsy in phenylketonuria: a complex dependence on serum phenylalanine levels.

PURPOSE: Phenylketonuria (PKU) is a disorder of phenylalanine (Phe) metabolism that frequently results in epilepsy if a low Phe diet was not implemented at birth. The mechanisms by which Phe affects the brain are poorly understood. METHODS: Audiogenic seizures (AGS) were studied in female homozygous Pah(enu2) BTBR (PKU) mice. RESULTS: Adult PKU mice, 18-20 weeks of age, in contrast to wild-type and heterozygous counterparts, exhibited a full range of AGS. Younger PKU mice, 5-7 weeks of age, had higher serum Phe levels (2.22 +/- 0.20 mM) in comparison with the adult animals (1.72 +/- 0.05 mM) and were not susceptible to AGS. Among adult mice, animals susceptible to AGS had significantly lower serum Phe levels (1.62 +/- 0.06 mM) in comparison with those resistant to AGS (1.86 +/- 0.07 mM). Susceptibility to AGS tended to increase in the afternoon when serum Phe concentration decreased in comparison to evening and morning. Normalization of serum Phe level by instituting a low Phe diet generally prevented susceptibility to AGS within 12 h. Although return to a standard diet raised Phe levels to hyperphenylalaninemic within 12 h in animals treated with a low Phe diet for 2 weeks, more than 7 weeks were needed for a complete resumption of AGS. CONCLUSIONS: Transient decrease in Phe levels within hyperphenylalaninemic range may be a necessary condition for PKU-related seizures to occur. A low Phe diet prevents susceptibility to seizures, which can resume with the significant delay after termination of dietary treatment.

Influence of carbenoxolone on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice.

Carbenoxolone, the succinyl ester of glycyrrhetinic acid, is an inhibitor of 11beta-hydroxy steroid dehydrogenase and gap junctional intercellular communication. It is currently used in clinical treatment of ulcer diseases. Systemic administration of carbenoxolone (1-40 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. Glycyrrhizin, an analogue of carbenoxolone inactive at the gap-junction level, was unable to affect audiogenic seizures at doses up to 30 mg/kg. In combination with conventional antiepileptic drugs, carbenoxolone, 0.5 mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic seizures in DBA/2 mice, potentiated the anticonvulsant activity of carbamazepine, diazepam, felbamate, gabapentin, lamotrigine, phenytoin, phenobarbital and valproate against sound-induced seizures in DBA/2 mice. This effect was not observed after the combination of glycyrrhizin (10 mg/kg, i.p.) with some conventional antiepileptic drugs. The degree of potentiation induced by carbenoxolone was greater for diazepam, felbamate, gabapentin, phenobarbital and valproate, less for lamotrigine, phenytoin and carbamazepine. This increase was associated with a comparable impairment in motor activity; however, the therapeutic index of combined treatment of antiepileptic drugs with carbenoxolone was more favourable than the combination with glycyrrhizin or saline. Since carbenoxolone did not significantly influence the total and free plasma levels of diazepam, felbamate, gabapentin, lamotrigine, phenytoin, phenobarbital, valproate and carbamazepine, pharmacokinetic interactions are not likely. However, the possibility that carbenoxolone can modify the brain clearance of the anticonvulsant drugs studied may not be excluded. In addition, carbenoxolone did not significantly affect the hypothermic effects of the anticonvulsants tested. In conclusion, carbenoxolone showed an additive anticonvulsant effect when administered in combination with some classical anticonvulsants, most notably diazepam, felbamate, gabapentin, phenobarbital, and valproate, implicating a possible therapeutic relevance of such drug combinations.

Effect of lactation on the expression of audiogenic seizures: association with plasma prolactin profiles.

Female Wistar rats and Wistar audiogenic rats (WARs) were used to investigate the potential roles of prolactin (PRL) and progesterone in the modulation of seizure expression. Animals were screened for seizure severity in both groups. All WARs at least displayed tonic-clonic convulsions followed by clonic spasms (TC) whereas none of the Wistar rats displayed seizures (Resistant). After seizures the plasma level of PRL in nulliparous female WARs increased about 8-fold compared to their basal levels and to the levels of Resistant animals. This value was still significantly higher than basal levels 15 min later. Lactation produced a decrease in the TC proportion in seizures in WARs both with and without pups. Two sub-populations of animals could be characterized: one that had TC suppressed (low seizure severity; LSS) and one that did not (high seizure severity; HSS). In animals of the LSS subgroup, either with or without pups, seizure severity decreased gradually and lowest values were seen on the 30th day after delivery. The temporal profile of plasma PRL during a 90-min period of suckling without sound stimulation showed significantly higher levels for LSS, the HSS levels being similar to those of the Resistant group. A progressive decrease in the group means for progesterone plasma concentration between the 9th and 29th days of lactation was detected in Resistant rats (P<0.05) but not in WARs. No significant differences between groups were revealed by comparison of the overall means. Taken together these data confirm the presence of a clear-cut post-ictal PRL peak after TC with a decrease in seizure severity in female WARs with and without pups. An eventual long-term role of PRL in modulating seizure activity might be related to the multifactorial physiological conditions of both pregnancy and lactation.

Comparison of a short irradiation (50 sec) by different wavelengths on audiogenic seizures in magnesium-deficient mice: evidence for a preventive neuroprotective effect of yellow.

Audiogenic seizures triggered by an acoustic stimulus of determined frequency and amplitude have been described in many laboratory animals in many circumstances including magnesium deficiency. This model, recently validated, was used, in DBA/2 mice, to study the preventive neuroprotective effect of 6 wavelengths of the visible spectrum used in Chromatotherapia* (lambda(max) 440, 484, 528, 572, 616 and 660 nm) at low irradiance. Each short illumination lasted 50 seconds and was followed by 20 minutes of darkness. It appeared that yellow fully protected 16 out of 17 mice from seizure occurrence. Green allowed the survival of 69% of mice but did not protect them from seizure occurrence. On the contrary, the other four colors (orange, red, purple and blue) failed to protect the mice and showed a tendency to accelerate their death. White color was not protective but allowed the difficult survival of 30% of mice. Darkness had no protective effect. These results even though surprising open a great field of investigation.

Cerebral excitability and the mechanisms of blood transportation of sodium.

The basic, fundamental property of living structures is excitability. This process defines how an organism responds to both internal and external stimuli. Previous studies have indicated the existence of physical and chemical interactions between cations and anions sites of proteins within the extracellular environment that have a specific functional importance. However, it is not well understood whether specific cations may alter the function of specific proteins. We report here the results of studies that indicate interaction of specific cations such as sodium may alter the physico-chemical action of heparin. The importance of these interactions is discussed.