Neuroendocrinological aspects of epilepsy: important issues and trends in future research

Case Report: Hypopituitarism Presenting With Nonconvulsive Status Epilepticus

Introduction: Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies. Nonconvulsive status epilepticus (NCSE) refers to a state of continuous or repetitive seizures without convulsions. In this paper, we review a case of an old female patient with hypopituitarism who presented with NCSE, which is rare in the clinic.

Case Report: This paper describes a 67-year-old female patient with hypopituitarism who presented as NCSE. She had surgical resection of pituitary tumor half a year before the seizures and did not get regular hormone replacement therapy. She presented general convulsive status epilepsy as the initial symptom and got sedation and antiepileptic drug in the emergency room. The seizure was terminated but the patient fell in coma in the following days. The patient had magnetic resonance imaging (MRI) and other inspects, and EEG showed epileptic discharges. Combining these clinical symptoms and examinations, we made the diagnosis of NCSE. Finally, she regained consciousness after the treatment with diazepam.

Conclusion: This case report and literature review investigated the possible mechanism of hypopituitarism presenting with NCSE.

Dehydroepiandrosterone (DHEA) Serum Levels Indicate Cerebrospinal Fluid Levels of DHEA and Estradiol (E2) in Women at Term Pregnancy

Neuroactive steroids such as dehydroepiandrosterone (DHEA), estradiol (E2), and progesterone (P4) are associated with structural and functional changes in the central nervous system (CNS). Measurement of steroid levels in the CNS compartments is restricted in accessibility. Consequently, there is only limited human data on the distributional equilibrium for steroid levels between peripheral and central compartments. While some neuroactive steroids including DHEA and E2 have been reported to convey excitatory and proconvulsant properties, the opposite was demonstrated for P4. We aimed to elucidate the correlation between peripheral and central DHEA, E2, and P4 levels in women at term pregnancy. CSF and serum samples of 27 healthy pregnant women (22–39 years) at term pregnancy were collected simultaneously under combined spinal and epidural anesthesia and used for DHEA ELISA and E2, and P4 ECLIA. All three neuroactive steroids were detected at markedly lower levels in CSF compared to their corresponding serum concentrations (decrease, mean ± SD, 97.66 ± 0.83%). We found a strong correlation for DHEA between its serum and the corresponding CSF levels (r = 0.65, p = 0.003). Serum and CSF levels of E2 (r = 0.31, p = 0.12) appeared not to correlate in the investigated cohort. DHEA serum concentration correlated significantly with E2 (r = 0.58, p = 0.0016) in CSF. In addition, a strong correlation was found between DHEA and E2, both measured in CSF (r = 0.65, p = 0.0002). Peripheral DHEA levels might serve as an indicator for central nervous levels of the neuroactive steroids DHEA and E2 in pregnant women.

Effects of androsterone on the protective action of various antiepileptic drugs against maximal electroshock-induced seizures in mice

This study evaluated the effect of androsterone (AND), a metabolite of testosterone, on the ability of selected classical and novel antiepileptic drugs to prevent seizures caused by maximal electroshock (MES), which may serve as an experimental model of human generalized tonic-clonic seizures in mice. Single intraperitoneal (i.p.) administration of AND (80 mg kg^-1) significantly raised the threshold for convulsions in the MES seizure threshold test. Lower doses of AND (5, 10, 20, and 40 mg kg^-1) failed to change the threshold. AND at a subthreshold dose of 40 mg kg^-1 significantly enhanced the protective activity of carbamazepine, gabapentin, and phenobarbital against MES-induced seizures decreasing their median effective doses (ED₅₀) values ± SEM from 8.59 ± 0.76 to 6.05 ± 0.81 mg kg^-1 (p = 0.0308) for carbamazepine, from 419.9 ± 120.6 to 111.5 ± 41.1 mg kg^-1 (p = 0.0405) for gabapentin, and from 20.86 ± 1.64 to 10.0 ± 1.21 mg kg^-1 (p = 0.0007) for phenobarbital. There were no significant changes in total brain concentrations of carbamazepine, gabapentin, and phenobarbital following AND administration. This suggests that the enhancing effects of AND on the protective activity of these antiepileptic drugs are not related to pharmacokinetic factors. A lower dose of AND (20 mg kg^-1) had no effect on the protective activity of carbamazepine, gabapentin, and phenobarbital. AND administered at a dose of 40 mg kg^-1 failed to change the anticonvulsant activity of lamotrigine, oxcarbazepine, phenytoin, topiramate, and valproate in the MES test. In the chimney test, AND given at a dose enhancing the protective activity of carbamazepine, gabapentin, and phenobarbital (which alone was without effect on motor performance of mice) did not affect impairment of motor coordination produced by the antiepileptics. Our findings recommend further preclinical and clinical research on AND in respect of its use as adjuvant therapy in the management of epilepsy in men with deficiency of androgens.

Genetic and Molecular Regulation of Extrasynaptic GABA-A Receptors in the Brain: Therapeutic Insights for Epilepsy

GABA-A receptors play a pivotal role in many brain diseases. Epilepsy is caused by acquired conditions and genetic defects in GABA receptor channels regulating neuronal excitability in the brain. The latter is referred to as GABA channelopathies. In the last two decades, major advances have been made in the genetics of epilepsy. The presence of specific GABAergic genetic abnormalities leading to some of the classic epileptic syndromes has been identified. Advances in molecular cloning and recombinant systems have helped characterize mutations in GABA-A receptor subunit genes in clinical neurology. GABA-A receptors are the prime targets for neurosteroids (NSs). However, GABA-A receptors are not static but undergo rapid changes in their number or composition in response to the neuroendocrine milieu. This review describes the recent advances in the genetic and neuroendocrine control of extrasynaptic and synaptic GABA-A receptors in epilepsy and its impact on neurologic conditions. It highlights the current knowledge of GABA genetics in epilepsy, with an emphasis on the neuroendocrine regulation of extrasynaptic GABA-A receptors in network excitability and seizure susceptibility. Recent advances in molecular regulation of extrasynaptic GABA-A receptor-mediated tonic inhibition are providing unique new therapeutic approaches for epilepsy, status epilepticus, and certain brain disorders. The discovery of an extrasynaptic molecular mechanism represents a milestone for developing novel therapies such as NS replacement therapy for catamenial epilepsy.

Catamenial-like seizure exacerbation in mice with targeted ablation of extrasynaptic δGABA-a receptors in the brain

Neurosteroids play a key role in catamenial epilepsy, a menstrual cycle-related seizure clustering in women with epilepsy. While neurosteroids act on all GABA-A receptor isoforms, they cause greater effects on extrasynaptic δGABA-A receptors that mediate tonic inhibition in the brain. Previously, we identified a potential GABA-A receptor mechanism for catamenial epilepsy. However, the precise functional role of extrasynaptic δGABA-A receptors in the pathophysiology of catamenial epilepsy remains unclear. In this study, we utilized mice lacking extrasynaptic δGABA-A receptors (δKO) to investigate whether reduction of tonic inhibition affects catamenial seizure susceptibility or intensity. Intact female wildtype (WT) and δKO mice were subjected to hippocampus kindling until they exhibited stage 5 seizures. Elevated gonadal hormone-based neurosteroid levels were induced by standard gonadotropin regimen and neurosteroid withdrawal (NSW) was triggered by finasteride. NSW increased susceptibility to, as well the intensity of evoked catamenial-like seizures in WT and δKO mice. However, fully kindled δKO mice exhibited an accelerated and augmented response to NSW, with a more rapid increase in seizure susceptibility and intensity than WT mice undergoing the NSW paradigm. Moreover, δKO mice in NSW showed reduced benzodiazepine sensitivity, but in stark contrast to the increased neurosteroid sensitivity observed in WT animals, δKO mice displayed no change in neurosteroid sensitivity in response to NSW. The increased catamenial seizure exacerbation and alterations in antiseizure drug responses are consistent with NSW-induced changes in the abundance of δGABA-A receptors. Collectively, these findings provide evidence of a potential protective role for extrasynaptic δGABA-A receptors in catamenial-like seizures. © 2017 Wiley Periodicals, Inc.

Catamenial Epilepsy: Discovery of an Extrasynaptic Molecular Mechanism for Targeted Therapy

Catamenial epilepsy is a type of refractory epilepsy characterized by seizure clusters around perimenstrual or periovulatory period. The pathophysiology of catamenial epilepsy still remains unclear, yet there are few animal models to study this gender-specific disorder. The pathophysiology of perimenstrual catamenial epilepsy involves the withdrawal of the progesterone-derived GABAergic neurosteroids due to the decline in progesterone level at the time of menstruation. These manifestations can be faithfully reproduced in rodents by specific neuroendocrine manipulations. Since mice and rats, like humans, have ovarian cycles with circulating hormones, they appear to be suitable animal models for studies of perimenstrual seizures. Recently, we created specific experimental models to mimic perimenstrual seizures. Studies in rat and mouse models of catamenial epilepsy show enhanced susceptibility to seizures or increased seizure exacerbations following neurosteroid withdrawal. During such a seizure exacerbation period, there is a striking decrease in the anticonvulsant effect of commonly prescribed antiepileptics, such as benzodiazepines, but an increase in the anticonvulsant potency of exogenous neurosteroids. We discovered an extrasynaptic molecular mechanism of catamenial epilepsy. In essence, extrasynaptic δGABA-A receptors are upregulated during perimenstrual-like neuroendocrine milieu. Consequently, there is enhanced antiseizure efficacy of neurosteroids in catamenial models because δGABA-A receptors confer neurosteroid sensitivity and greater seizure protection. Molecular mechanisms such as these offer a strong rationale for the clinical development of a neurosteroid replacement therapy for catamenial epilepsy.

Efficacy of Attribution Retraining on Mental Health of Epileptic Children

Background:

Epilepsy affects children’s quality of life and leads to social and mental problems. Promoting the mental health of children, especially epileptic ones, and preventing problems affecting them constitute major concerns for every country. Mental health promotion requires intervention programs.

Objectives:

We sought to assess the efficacy of attribution retraining on the mental health of epileptic children.

Patients and Methods:

The present study is a semi-experimental investigation with a pretest and posttest design and includes a control group. Thirty children, comprising 17 boys and 13 girls, were selected randomly from the Iranian epilepsy association in Tehran and assigned to experimental and control groups. They answered to the general health questionnaire (Goldberg and Hiller, 1979). The experimental group participated in 11 training sessions (twice a week; 45 minutes for each session) and received attribution retraining. The data were analyzed using the multiple analysis of covariance.

Results:

The findings showed that the experimental group, in comparison with the control group, experienced a reduction in physical symptoms, anxiety and insomnia, social dysfunction, and depression and an increase in mental health significantly (P < 0.01) after the training sessions. There were no significant differences, however, between the two groups at 6 weeks’ follow-up.

Conclusions:

Attribution retraining improved mental health in the epileptic children in our study. It, therefore, seems to be an appropriate intervention for promoting the mental health of children.

Perimenstrual-like hormonal regulation of extrasynaptic δ-containing GABAA receptors mediating tonic inhibition and neurosteroid sensitivity

Neurosteroids are endogenous regulators of neuronal excitability and seizure susceptibility. Neurosteroids, such as allopregnanolone (AP; 3α-hydroxy-5α-pregnan-20-one), exhibit enhanced anticonvulsant activity in perimenstrual catamenial epilepsy, a neuroendocrine condition in which seizures are clustered around the menstrual period associated with neurosteroid withdrawal (NSW). However, the molecular mechanisms underlying such enhanced neurosteroid sensitivity remain unclear. Neurosteroids are allosteric modulators of both synaptic (αβγ2-containing) and extrasynaptic (αβδ-containing) GABAA receptors, but they display greater sensitivity toward δ-subunit receptors in dentate gyrus granule cells (DGGCs). Here we report a novel plasticity of extrasynaptic δ-containing GABAA receptors in the dentate gyrus in a mouse perimenstrual-like model of NSW. In molecular and immunofluorescence studies, a significant increase occurred in δ subunits, but not α1, α2, β2, and γ2 subunits, in the dentate gyrus of NSW mice. Electrophysiological studies confirmed enhanced sensitivity to AP potentiation of GABA-gated currents in DGGCs, but not in CA1 pyramidal cells, in NSW animals. AP produced a greater potentiation of tonic currents in DGGCs of NSW animals, and such enhanced AP sensitivity was not evident in δ-subunit knock-out mice subjected to a similar withdrawal paradigm. In behavioral studies, mice undergoing NSW exhibited enhanced seizure susceptibility to hippocampus kindling. AP has enhanced anticonvulsant effects in fully kindled wild-type mice, but not δ-subunit knock-out mice, undergoing NSW-induced seizures, confirming δ-linked neurosteroid sensitivity. These results indicate that perimenstrual NSW is associated with striking upregulation of extrasynaptic, δ-containing GABAA receptors that mediate tonic inhibition and neurosteroid sensitivity in the dentate gyrus. These findings may represent a molecular rationale for neurosteroid therapy of catamenial epilepsy.

Antiepileptic medications increase osteoporosis risk in male fabry patients: bone mineral density in an Australian cohort

BACKGROUND

Fabry disease (FD) is an inherited X-linked lysosomal storage disease with widespread clinical manifestations. Small prospective studies have shown increased osteopenia and osteoporosis in male FD patients. Limited information however exists about bone metabolism and osteoporosis risk factors within this group. We reviewed osteoporosis risk factors within our cohort.

METHODS

A retrospective analysis of bone mineral density (BMD) results and fracture incidence in 44 patients (22 males and 22 females) was undertaken. Dual X-ray absorptiometry scans were performed at the lumbar spine, hip and femoral neck. The impact of risk factors including renal function, antiepileptic drug (AED), analgesia and vitamin D levels were assessed.

RESULTS

Male FD patients had low T scores at all sites (spine -1.2 ± 1.06, hip -1.6 ± 0.9, femoral neck -2.23 ± 1.01). Female T scores showed more typical distribution (spine -0.07 ± 1.47, hip 0.02 ± 1.14, femoral neck -0.49 ± 1.31). A higher incidence of osteopenia and/or osteoporosis occurred in males versus females (spine 46.9% versus 31.8%, hip 75.5% versus 18.2% and femoral neck 86.4% versus 45.5%). Multiple regression analysis showed a 50.8% (p < 0.001) reduction in femoral neck BMD with AED usage, after adjustment for age, gender and renal function. Non-traumatic fractures occurred in 27.3% males over 205 patient-years versus 4.6% in females over 149 patient-years, p = 0.095.

CONCLUSIONS

Low bone density was highly prevalent in male patients with increased incidence of non-traumatic fractures. AED usage significantly reduces BMD. Treatment to prevent BMD deterioration will depend on determining the bone turnover status.

Neurologic complications of nondiabetic endocrine disorders

PURPOSE OF REVIEW

This article provides an overview of the neurologic complications found in the various endocrine disorders affecting adult patients. Specifically, disorders in pituitary hormones (prolactin, growth hormone, vasopressin, and oxytocin), thyroid hormones, adrenal hormones (glucocorticoids), and sex hormones (estrogen and testosterone) will be covered, with an emphasis on identifying the signs and symptoms in addition to diagnosing and managing these disorders.

RECENT FINDINGS

Hyperthyroidism in the young was found to increase the risk for ischemic stroke in a recent prospective case-cohort study. The cognitive effects of hormonal therapy in postmenopausal women remain controversial, but a recent study found no benefit or risk in cognitive function when treating younger (50 to 55 years of age) postmenopausal women with hormonal therapy.

SUMMARY

Endocrine disorders can cause various neurologic complications, from insidious myopathy to acute encephalopathy. Diagnosing the endocrine disorder as the cause of the neurologic impairment is essential, as treating the underlying hormonal dysfunction will often rapidly reverse the neurologic symptoms. Ongoing research is needed to further clarify the role of hormonal dysfunction in neurologic disorders.

Novel anticonvulsive effects of progesterone in a mouse model of hippocampal electrical kindling

Progesterone is a known anticonvulsant, with its inhibitory effects generally attributed to its secondary metabolite, 5α,3α-tetrahydroprogesterone (THP), and THP's enhancement of GABAA receptor activity. Accumulating evidence, however, suggests that progesterone may have non-genomic actions independent of the GABAA receptor. In this study, we explored THP/GABAA-independent anticonvulsive actions of progesterone in a mouse model of hippocampal kindling and in mouse entorhinal slices in vitro. Specifically, we examined the effects of progesterone in kindled mice with or without pretreatments with finasteride, a 5α-reductase inhibitor known to block the metabolism of progesterone to THP. In addition, we examined the effects of progesterone on entorhinal epileptiform potentials in the presence of a GABAA receptor antagonist picrotoxin and finasteride. Adult male mice were kindled via a daily stimulation protocol. Electroencephalographic (EEG) discharges were recorded from the hippocampus or cortex to assess "focal" or "generalized" seizure activity. Kindled mice were treated with intra-peritoneal injections of progesterone (10, 35, 100 and 160mg/kg) with or without finasteride pretreatment (50 or 100mg/kg), THP (1, 3.5, 10 and 30mg/kg), midazolam (2mg/kg) and carbamazepine (50mg/kg). Entorhinal cortical slices were prepared from naïve young mice, and repetitive epileptiform potentials were induced by 4-aminopyridine (100μM), picrotoxin (100μM) and finasteride (1μM). Pretreatment with finasteride did not abolish the anticonvulsant effects of progesterone. In finasteride-pretreated mice, progesterone at 100 and 160mg/kg decreased cortical but not hippocampal afterdischarges (ADs). Carbamazepine mimicked the effects of progesterone with finasteride pretreatments in decreasing cortical discharges and motor seizures, whereas midazolam produced effects similar to progesterone alone or THP in decreasing hippocampal ADs and motor seizures. In brain slices, progesterone at 1μM inhibited entorhinal epileptiform potentials in the presence of picrotoxin and finasteride. We suggest that progesterone may have THP/GABAA-dependent and independent anticonvulsive actions in the hippocampal-kindled mouse model.

Estrous cycle regulation of extrasynaptic δ-containing GABA(A) receptor-mediated tonic inhibition and limbic epileptogenesis

The ovarian cycle affects susceptibility to behavioral and neurologic conditions. The molecular mechanisms underlying these changes are poorly understood. Deficits in cyclical fluctuations in steroid hormones and receptor plasticity play a central role in physiologic and pathophysiologic menstrual conditions. It has been suggested that synaptic GABA(A) receptors mediate phasic inhibition in the hippocampus and extrasynaptic receptors mediate tonic inhibition in the dentate gyrus. Here we report a novel role of extrasynaptic δ-containing GABA(A) receptors as crucial mediators of the estrous cycle-related changes in neuronal excitability in mice, with hippocampus subfield specificity. In molecular and immunofluorescence studies, a significant increase occurred in δ-subunit, but not α4- and γ2-subunits, in the dentate gyrus during diestrus. However, δ-subunit upregulation was not evident in the CA1 region. The δ-subunit expression was undiminished by age and ovariectomy and in mice lacking progesterone receptors, but it was significantly reduced by finasteride, a neurosteroid synthesis inhibitor. Electrophysiologic studies confirmed greater potentiation of GABA currents by progesterone-derived neurosteroid allopregnanolone in dissociated dentate gyrus granule cells in diestrus than in CA1 pyramidal cells. The baseline conductance and allopregnanolone potentiation of tonic currents in dentate granule cells from hippocampal slices were higher than in CA1 pyramidal cells. In behavioral studies, susceptibility to hippocampus kindling epileptogenesis was lower in mice during diestrus. These results demonstrate the estrous cycle-related plasticity of neurosteroid-sensitive, δ-containing GABA(A) receptors that mediate tonic inhibition and seizure susceptibility. These findings may provide novel insight on molecular cascades of menstrual disorders like catamenial epilepsy, premenstrual syndrome, and migraine.

Neuroendocrine aspects of catamenial epilepsy

This review describes the neuroendocrinological aspects of catamenial epilepsy, a menstrual cycle-related seizure disorder in women with epilepsy. Catamenial epilepsy is a multifaceted neuroendocrine condition in which seizures are clustered around specific points in the menstrual cycle, most often around perimenstrual or periovulatory period. Three types of catamenial seizures (perimenstrual, periovulatory and inadequate luteal) have been identified. The molecular pathophysiology of catamenial epilepsy remains unclear. Cyclical changes in the circulating levels of estrogens and progesterone (P) play a central role in the development of catamenial epilepsy. Endogenous neurosteroids such as allopregnanolone (AP) and allotetrahydrodeoxycorticosterone (THDOC) that modulate seizure susceptibility could play a critical role in catamenial epilepsy. In addition, plasticity in GABA-A receptor subunits could play a role in the enhanced seizure susceptibility in catamenial epilepsy. P-derived neurosteroids such as AP and THDOC potentiate synaptic GABA-A receptor function and also activate extrasynaptic GABA-A receptors in the hippocampus and thus may represent endogenous regulators of catamenial seizure susceptibility. Experimental studies have shown that neurosteroids confer greater seizure protection in animal models of catamenial epilepsy, especially without evident tolerance to their actions during chronic therapy. In the recently completed NIH-sponsored, placebo controlled phase 3 clinical trial, P therapy proved to be beneficial only in women with perimenstrual catamenial epilepsy but not in non-catamenial subjects. Neurosteroid analogs with favorable profile may be useful in the treatment of catamenial epilepsy.

Neuroendocrine considerations in the treatment of men and women with epilepsy

Complex, multidirectional interactions between hormones, seizures, and the medications used to control them can present a challenge for clinicians treating patients with epilepsy. Many hormones act as neurosteroids, modulating brain excitability via direct binding sites. Thus, changes in endogenous or exogenous hormone levels can affect the occurrence of seizures directly as well as indirectly through pharmacokinetic effects that alter the concentrations of antiepileptic drugs. The underlying structural and physiological brain abnormalities of epilepsy and the metabolic activity of antiepileptic drugs can adversely affect hypothalamic and gonadal functioning. Knowledge of these complex interactions has increased and can now be incorporated in meaningful treatment approaches for men and women with epilepsy.

Brains, bones, and aging: psychotropic medications and bone health among older adults

Psychotropic drugs are a crucial element of treatment for psychiatric disorders; however there is an established association between many classes of psychotropic medications and fracture risk among older adults, and growing evidence that some classes of medications may also impact bone mineral density (BMD). In this paper we review recent epidemiologic research on the association between psychotropic medications and osteoporosis, and discuss current controversies and unresolved issues surrounding this relationship. Key areas in need of focused inquiry include resolving whether the apparent association between psychotropic medications and BMD is due to confounding by indication, whether this relationship differs for men and women, and whether the implications of these medications for bone health vary over the life course. Clinical research to delineate the risk/benefit ratio of psychotropic medications for older adults, particularly those who are at high risk for fracture, is also needed to facilitate prescribing decisions between patients and physicians.

Identification of compounds with anti-convulsant properties in a zebrafish model of epileptic seizures

The availability of animal models of epileptic seizures provides opportunities to identify novel anticonvulsants for the treatment of people with epilepsy. We found that exposure of 2-day-old zebrafish embryos to the convulsant agent pentylenetetrazole (PTZ) rapidly induces the expression of synaptic-activity-regulated genes in the CNS, and elicited vigorous episodes of calcium (Ca(2+)) flux in muscle cells as well as intense locomotor activity. We then screened a library of ∼2000 known bioactive small molecules and identified 46 compounds that suppressed PTZ-inducedtranscription of the synaptic-activity-regulated gene fos in 2-day-old (2 dpf) zebrafish embryos. Further analysis of a subset of these compounds, which included compounds with known and newly identified anticonvulsant properties, revealed that they exhibited concentration-dependent inhibition of both locomotor activity and PTZ-induced fos transcription, confirming their anticonvulsant characteristics. We conclude that this in situ hybridisation assay for fos transcription in the zebrafish embryonic CNS is a robust, high-throughput in vivo indicator of the neural response to convulsant treatment and lends itself well to chemical screening applications. Moreover, our results demonstrate that suppression of PTZ-induced fos expression provides a sensitive means of identifying compounds with anticonvulsant activities.

Skeletal parasympathetic innervation communicates central IL-1 signals regulating bone mass accrual

Bone mass accrual is a major determinant of skeletal mass, governed by bone remodeling, which consists of bone resorption by osteoclasts and bone formation by osteoblasts. Bone mass accrual is inhibited by sympathetic signaling centrally regulated through activation of receptors for serotonin, leptin, and ACh. However, skeletal activity of the parasympathetic nervous system (PSNS) has not been reported at the bone level. Here we report skeletal immune-positive fibers for the PSNS marker vesicular ACh transporter (VAChT). Pseudorabies virus inoculated into the distal femoral metaphysis is identifiable in the sacral intermediolateral cell column and central autonomic nucleus, demonstrating PSNS femoral innervation originating in the spinal cord. The PSNS neurotransmitter ACh targets nicotinic (nAChRs), but not muscarinic receptors in bone cells, affecting mainly osteoclasts. nAChR agonists up-regulate osteoclast apoptosis and restrain bone resorption. Mice deficient of the α(2)nAChR subunit have increased bone resorption and low bone mass. Silencing of the IL-1 receptor signaling in the central nervous system by brain-specific overexpression of the human IL-1 receptor antagonist (hIL1ra(Ast)(+/+) mice) leads to very low skeletal VAChT expression and ACh levels. These mice also exhibit increased bone resorption and low bone mass. In WT but not in hIL1ra(Ast)(+/+) mice, the cholinergic ACh esterase inhibitor pyridostigmine increases ACh levels and bone mass apparently by inhibiting bone resorption. Taken together, these results identify a previously unexplored key central IL-1-parasympathetic-bone axis that antagonizes the skeletal sympathetic tone, thus potently favoring bone mass accrual.

Finasteride inhibits the disease-modifying activity of progesterone in the hippocampus kindling model of epileptogenesis

Progesterone (P) plays an important role in seizure susceptibility in women with epilepsy. Preclinical and experimental studies suggest that P appears to interrupt epileptogenesis, which is a process whereby a normal brain becomes progressively susceptible to recurrent, unprovoked seizures due to precipitating risk factors. Progesterone has not been investigated widely for its potential disease-modifying activity in epileptogenic models. Recently, P has been shown to exert disease-modifying effects in the kindling model of epileptogenesis. However, the mechanisms underlying the protective effects of P against epileptogenesis remain unclear. In this study, we investigated the role of P-derived neurosteroids in the disease-modifying activity of P. It is hypothesized that 5α-reductase converts P to allopregnanolone and related neurosteroids that retard epileptogenesis in the brain. To test this hypothesis, we utilized the mouse hippocampus kindling model of epileptogenesis and investigated the effect of finasteride, a 5α-reductase and neurosteroid synthesis inhibitor. Progesterone markedly retarded the development of epileptogenesis and inhibited the rate of kindling acquisition to elicit stage 5 seizures. Pretreatment with finasteride led to complete inhibition of the P-induced retardation of the limbic epileptogenesis in mice. Finasteride did not significantly influence the acute seizure expression in fully kindled mice expressing stage 5 seizures. Thus, neurosteroids that potentiate phasic and tonic inhibition in the hippocampus, such as allopregnanolone, may mediate the disease-modifying effect of P, indicating a new role of neurosteroids in acquired limbic epileptogenesis and temporal lobe epilepsy.

The course and outcome of pregnancy and neonatal situation in epileptic women

Background:

Epilepsy is a rare neurologic disorder during pregnancy. Despite its rarity, it could cause different clinical problems in this natural phenomenon of a woman's life. The aim of this study was to evaluate and compare the course of pregnancy and labor and their outcome in epileptic and healthy women.

Materials and Methods:

This study was performed during years 2009--2011 in Alzahra and Beheshti hospitals affiliated to Isfahan University of Medical Sciences. A total of 51 pregnant women, who were known cases of epilepsy and were on antiepileptic drugs treatment for at least 3 months, were compared with 47 matched healthy pregnant women without epilepsy. They were followed before and during their pregnancy in several visits and all of their neurologic and obstetric information were collected. For statistical analysis of continuous variables, the t-test was used. The chi-square test was used for dichotomous variables.

Results:

The rate of monotherapy was more than polytheraphy especially during the pregnancy. The epileptic attacks stopped in majority of patients during the pregnancy. Vaginal bleeding (P=0.020) and abortion (P=0.015) were significantly more frequent among epileptic mothers. The gestational age was lower meaningfully (P= 0.010) in epileptic patients’ neonates and the first minute Apgar score was lower in these babies too (P=0.028).

Conclusions:

Antiepileptic drugs could have some unsuitable effects on pregnancy course especially by increasing the rate of abortion, preterm labor, and vaginal bleeding. Their adverse effects on neonates’ health could not be neglected.

A mouse kindling model of perimenstrual catamenial epilepsy

Catamenial epilepsy is caused by fluctuations in progesterone-derived GABA(A) receptor-modulating anticonvulsant neurosteroids, such as allopregnanolone, that play a significant role in the pathophysiology of epilepsy. However, there is no specific mouse model of catamenial epilepsy. In this study, we developed and characterized a mouse model of catamenial epilepsy by using the neurosteroid-withdrawal paradigm. It is hypothesized that seizure susceptibility decreases when neurosteroid levels are high (midluteal phase) and increases during their withdrawal (perimenstrual periods) in close association with GABA(A) receptor plasticity. A chronic seizure condition was created by using the hippocampus kindling model in female mice. Elevated neurosteroid levels were induced by sequential gonadotropin treatment, and withdrawal was induced by the neurosteroid synthesis inhibitor finasteride. Elevated neurosteroid exposure reduced seizure expression in fully kindled mice. Fully kindled mice subjected to neurosteroid withdrawal showed increased generalized seizure frequency and intensity and enhanced seizure susceptibility. They also showed reduced benzodiazepine sensitivity and enhanced neurosteroid potency, similar to the clinical catamenial seizure phenotype. The increased susceptibility to seizures and alterations in antiseizure drug responses are associated with increased abundance of the α4 and δ subunits of GABA(A) receptors in the hippocampus. These findings demonstrate that endogenous neurosteroids protect against seizure susceptibility and their withdrawal, such as that which occurs during menstruation, leads to exacerbation of seizure activity. This is possibly caused by specific changes in GABA(A) receptor-subunit plasticity and function, therefore providing a novel mouse model of human perimenstrual catamenial epilepsy that can be used for the investigation of disease mechanisms and new therapeutic approaches.

Do lamotrigine and levetiracetam solve the problem of using sodium valproate in women with epilepsy?

Women with epilepsy, especially those of child-bearing age, are faced with difficult choices when it comes to choosing the most suitable antiepileptic drug (AED). This is particularly so for those with idiopathic generalized epilepsies, or those for whom seizure syndrome is not immediately apparent, where sodium valproate is still considered the drug of choice. While with treatment most might expect to become seizure free, without any adverse effects, other considerations for women mean that valproate is usually initially avoided, with other AEDs such as lamotrigine or levetiracetam being chosen in preference. Based on current information, this article attempts to provide an overview on whether or not the availability of these and other broad-spectrum AEDs have solved the difficulties of using valproate in women of child-bearing age.

Integrins as receptor targets for neurological disorders

This review focuses on the neurobiology of integrins, pathophysiological roles of integrins in neuroplasticity and nervous system disorders, and therapeutic implications of integrins as potential drug targets and possible delivery pathways. Neuroplasticity is a central phenomenon in many neurological conditions such as seizures, trauma, and traumatic brain injury. During the course of many brain diseases, in addition to intracellular compartment changes, alterations in non-cell compartments such as extracellular matrix (ECM) are recognized as an essential process in forming and reorganizing neural connections. Integrins are heterodimeric transmembrane receptors that mediate cell-ECM and cell-cell adhesion events. Although the mechanisms of neuroplasticity remain unclear, it has been suggested that integrins undergo plasticity including clustering through interactions with ECM proteins, modulating ion channels, intracellular Ca(2+) and protein kinase signaling, and reorganization of cytoskeletal filaments. As cell surface receptors, integrins are central to the pathophysiology of many brain diseases, such as epilepsy, and are potential targets for the development of new drugs for neurological disorders.