Valproic acid treated female Long-Evans rats are impaired on attentional set-shifting

Autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by social deficits, communication impairments, restrictive behaviors, and cognitive flexibility deficits. The valproic acid (VPA) model of autism has been widely used to examine changes in rodent behavior and neurobiology to better understand ASD. This study examined social and anxiety behavior as well as cognitive flexibility in VPA and control offspring. Results for social behavior were consistent with prior studies showing reduced sociability in VPA rats and increased self-grooming, which may be viewed as a repetitive behavior. VPA rats also had deficits in performing the set-shifting task, with female VPA rats demonstrating greater impairment compared to female control rats and male VPA rats. These results support the hypothesis that females diagnosed with ASD may suffer from different symptoms and present a unique behavioral profile compared to males with ASD. Female VPA rats were also less likely to form an attentional set; offering evidence that the VPA model of autism is encompassing executive function deficits similar to those observed in humans with ASD.

Intervention effect of gamma aminobutyric acid on anxiety behavior induced by phthalate (2-ethylhexyl ester) in rats

BACKGROUND

Di(2-ethylhexyl) phthalate (DEHP) is one of the most widely used phthalate esters. The application of DEHP has caused serious environmental pollution and posed a threat to human health.

METHODS

A total of 30 male Sprague-Dawley rats were randomly divided into control group, DEHP group (500 mg/kg DEHP), low GABA (Gama-aminobutyric acid) group (500 mg/kg DEHP and 1 mg/kg GABA), medium GABA group (500 mg/kg DEHP and 2 mg/kg GABA) and high GABA group (500 mg/kg DEHP and 4 mg/kg GABA). The interventions continued for 30 consecutive days. Open-field test and elevated plus-maze test were used to detect behavioral changes of rats before and after interventions.

RESULTS

The levels of nitric oxide and nitric oxide synthase in prefrontal cortex of rats were measured using enzyme-linked immunosorbent assay. DEHP and GABA treatment had no significant effects on the body weight of rats. GABA restored food utilization rate of rats impaired by DEHP to the level of healthy rats. According to open-field test and elevated plus-maze test, GABA alleviated the effects of DEHP on rat behaviors. Enzyme-linked immunosorbent assay showed that GABA was effective in reducing the levels of nitric oxide and nitric oxide synthase in rats treated with DEHP.

CONCLUSION

DEHP exposure induced anxiety in rats, which may be achieved through elevating nitric oxide and nitric oxide synthase levels in prefrontal cortex of rats. However, the effects caused by DEHP could be alleviated by GABA.

Electrophoretic drug delivery for seizure control

The persistence of intractable neurological disorders necessitates novel therapeutic solutions. We demonstrate the utility of direct in situ electrophoretic drug delivery to treat neurological disorders. We present a neural probe incorporating a microfluidic ion pump (μFIP) for on-demand drug delivery and electrodes for recording local neural activity. The μFIP works by electrophoretically pumping ions across an ion exchange membrane and thereby delivers only the drug of interest and not the solvent. This "dry" delivery enables precise drug release into the brain region with negligible local pressure increase. The therapeutic potential of the μFIP probe is tested in a rodent model of epilepsy. The μFIP probe can detect pathological activity and then intervene to stop seizures by delivering inhibitory neurotransmitters directly to the seizure source. We anticipate that further tailored engineering of the μFIP platform will enable additional applications in neural interfacing and the treatment of neurological disorders.

Therapeutic potential of valproic acid in advanced glaucoma: A pilot study

Purpose

Oral valproic acid (VPA) used as an anticonvulsant has been shown to improve contrast threshold sensitivities in patients receiving it on long-term. This study aimed to evaluate the efficacy of oral VPA in improving visual function in eyes with advanced stage glaucoma.

Methods

In this prospective randomized study, 31 patients (n = 31 eyes) with advanced stage glaucoma (with an intraocular pressure <16 mmHg) in at least one eye received oral VPA 500 mg once a day for 3 months and 33 patients (n = 33 eyes) continued on glaucoma therapy. Patients were followed up at 3 and 12 months (to evaluate the legacy effect of the drug). Blood VPA concentrations were measured at 3 months. Following parameters were assessed at baseline, 3 months and 12 months: log of the minimum angle of resolution (LogMAR) visual acuity, mean deviation on visual fields, and multifocal electroretinogram (ERG).

Results

Median LogMar visual acuity in the VPA group improved from 0.3 at baseline to 0.18 and 0.18 at 3 and 12 months, respectively (P < 0.01). In comparison, the median visual acuity in control group at baseline was 0.18 and showed neither worsening nor improvement over 3 and 12 months (P = 0.56). The improvement in VPA group was significant compared to the control group (P < 0.01; Wilcoxon Signed-rank test). An improvement in one line was experienced in 11 out of 31 eyes in the VPA group compared to 1 out of 33 eyes among controls (P = 0.003). No significant improvement was noted in the mean deviation, and the multifocal ERG (Latency and amplitudes) in the VPA-treated patients. The average blood VPA concentration measured at 3 months of therapy was 26 ± 8.9 μg/ml (range 8-55 μg/ml) which is much lower than that achieved during anticonvulsant therapy. None of the patients complained of any adverse effects that required stopping VPA therapy.

Conclusion

A 3 months oral VPA therapy results in some improvement in visual acuity in a subgroup of eyes with advanced glaucoma and the effect was seen to persist 9 months after the drug was stopped.

Effect of feeding Rumen-protected capsule containing niacin, K2SO4, vitamin C, and gamma-aminobutyric acid on heat stress and performance of dairy cows

This study was conducted to evaluate the effects of supplemental rumen-protected capsule (RPC) on animal performance, serological indicators, and serum heat shock protein 70 (HSP70) of lactating Holstein cows under heat stress (HS). During summer months, 30 healthy multiparous lactating Holstein cows with a parity number of 3.1 ± 0.44, 70 ± 15 d in milk, an average body weight of 622 ± 62kg, and an average milk yield of 32.28 ± 0.96kg/d, were used. The cows were randomly allocated to two groups: a control group and an RPC-supplemented group (0.13373kg K₂SO₄, 0.02488kg vitamin C, 0.021148kg niacin, and 0.044784kggamma-aminobutyric acid per cow). During the 42-d experiment, ambient air temperature and relative humidity inside and outside the barn were recorded hourly every day for the determination of temperature-humidity index (THI). Milk and blood samples were collected every week, and body weight and body condition scoring were measured on day 0. Based on the THI values, the animals had moderate HS. On day 42, the RPC group had lower HSP70, adrenocorticotropic hormone (P = 0.0001), lactate dehydrogenase (P = 0.0338), and IL-6 (P = 0.0724) levels than the control group, with no significant differences in creatine kinase, glucocorticoid, or IL-2 levels. Milk yield, energy-corrected milk, and dry matter intake were higher in RPC than in the control group (P = 0.0196). There were no significant differences in milk fat or daily protein levels between the two groups; however, daily protein and milk fat levels were higher in the RPC group than in the control group (P = 0.0114 and P = 0.0665, respectively). Somatic cell counts were no different between the two groups. In conclusion, RPC may alleviate HS and improve dairy cow performance.

The DRD3 Ser9Gly Polymorphism Predicted Metabolic Change in Drug-Naive Patients With Bipolar II Disorder

Patients with bipolar II disorder (BDII) have a higher prevalence rate of metabolic disturbance. Whether BDII itself, in addition to its current standard treatment, is a risk factor for metabolic syndrome warrants additional study. The dopamine receptor D3 (DRD3) gene, one of the candidate genes for BDII, is also involved in the dopaminergic system. We investigated whether it is related to changes in the metabolic indices of patients with BDII given 12 weeks of standard treatment.Patients with a first diagnosis of BDII (n = 117) were recruited. Metabolic profiles (cholesterol, triglycerides, fasting serum glucose, body mass index) were measured at baseline and at 2, 8, and 12 weeks. The genotype of the DRD3 Ser9Gly polymorphism (rs6280) was determined. Multiple linear regressions with generalized estimating equation methods were used.Seventy-six (65.0%) patients completed the 12-week intervention. Significant differences in triglyceride change were associated with the DRD3 Ser9Gly genotype (P = 0.03). Patients with the Ser/Ser genotype had significantly smaller triglyceride increases and a lower risk of developing metabolic syndrome than did those with the Ser/Gly+Gly/Gly genotype. However, the associations between the DRD3 Ser9Gly polymorphism with changes in triglyceride level become nonsignificant after correcting for multiple comparisons.We conclude that the DRD3 Ser9Gly polymorphism is nominally associated with changes in triglycerides and metabolic syndrome after 12 weeks of standard BDII treatment.

Intravenous sodium valproate aborts migraine headaches rapidly

OBJECTIVES

This preliminary study was designed to evaluate the efficacy and safety of intravenous sodium valproate in managing severe migraine headache.

DESIGN/METHODS

In a preliminary prospective open-label study, we treated patients with severe migraine headache using intravenous sodium valproate, after obtaining written informed consent. Thirty-six patients, hospitalized with acute established migraine, were infused with sodium valproate. The diagnosis of migraine was based on the International Headache Society classification criteria. Severity of headache was reported on 10-point visual analog. Disability was assessed on a five-point scale. Primary and secondary endpoints were measured as sustained pain relief and symptoms improvement at 2 h, respectively.

RESULTS

The study participants had a mean±SD age of 35.7±9.3 years. The loading dose of sodium valproate was 900-1200 mg, and the average time to best response for headache severity was 50 min. A reduction in pain from severe or moderate to mild or no pain in 60 min was reported in 75% of patients [OR=7.187 (95% confidence intervals: 1.32-38.95)]. After treatment with sodium valproate, headache severity was significantly decreased (P<0.0001). No serious adverse events were reported.

CONCLUSIONS

Intravenous Sodium Valproate (iVPA) seems to be safe and rapidly effective for intractable migraine attack. Randomized, double-blinded, controlled studies are warranted.

[Cerebrovascular effects of GABA conjugate with arachidonic acid under conditions of separate and combined vascular pathology of brain and heart]

Experiments on rats showed that, under conditions of global transient ischemia, a conjugate of GABA with arachidonic acid enhances the local cerebral blood flow due to a decrease in the vascular tone. In intact rats, the examined neurolipin did not show unidirectional changes in the cerebral perfusion. Under conditions of experimental myocardial infarction and combined vascular pathology of brain and heart, the GABA conjugate with arachidonic acid increased the blood flow in the parietal region of brain cortex in most experiments, while decreasing the level of blood pressure.

GABA(A) receptor signaling in the lateral septum regulates maternal aggression in mice

Maternal aggression (maternal defense) is a fierce aggression produced by lactating females toward intruders that plays an important role in protection of vulnerable offspring. Enhancement of GABA(A) receptor signaling by benzodiazepines increases maternal aggression, and we recently found indirect evidence that lateral septum (LS) could be a key site where benzodiazepines elevate aggression. In this study, we directly tested the hypothesis that activation of GABA(A) receptors in LS would promote maternal aggression while inhibition of this receptor would decrease aggression. Site-directed injections to LS were made using the GABA(A) receptor antagonist, bicuculline (3-30 ng), or the GABA(A) receptor agonists, chlordiazepoxide, a benzodiazepine (2.5-5 microg), and muscimol (0.05-5 ng). Maternal aggression and other behavioral measures were then evaluated in lactating mice. Neither GABA(A) receptor agonist elevated aggression, which could reflect a ceiling effect. However, 7 ng of the GABA(A) receptor antagonist, bicuculline, in LS significantly decreased maternal aggression without altering other maternal behaviors or light-dark box performance, suggesting some GABA(A) receptor signaling in LS is required for full maternal aggression expression. Together, these results confirm a role for GABA(A) receptor signaling in LS in the regulation of maternal aggression.

Effect of oral administration of GABA on temperature regulation in humans during rest and exercise at high ambient temperature

BACKGROUND

Centric administration of gamma-aminobutyric acid (GABA) has been implicated to affect temperature regulation in animals during rest or under anesthesia. However, there are few reports concerning the effects of the oral administration of GABA on temperature regulation in humans during rest and exercise. In order to clarify the effects and underlying mechanisms, we measured several parameters related to temperature regulation of humans during rest and exercise at high ambient temperature (35 degrees C).

METHODS

On two occasions, eight endurance-trained men rested for 20 min and cycled at 65% VO2peak for 30 min. In control trial (trial-C), subjects drank the sample which was a sports drink of 200 mL (placebo) before the rest period. In another trial (trial-G), subjects drank the sample which was a sports drink containing 1000 mg of GABA (GABA drink) before the rest period.

RESULTS

In trial-G, the plasma GABA concentrations were maintained higher than those in trial-C during the experiment. An increase of esophageal temperature during rest and exercise was inhibited in trial-G. Sweat rate, and plasma catecholamine concentrations during exercise were inhibited in trial-G.

CONCLUSIONS

Esophageal temperature inhibition is suggested to be induced by the suppression of cold-sensitive neurons during rest, and the inhibition of plasma catecholamine concentrations caused by the GABA-induced attenuation of the sympathetic nervous system during exercise.

[Effects of aminalon, fenibut, and picamilon on the typological parameters of cerebral hemodynamics in swimmers with dysadaptation syndrome]

The administration of aminalon (0.25 g), fenibut (0.25 g) and picamilon (0.10 g) during 4 weeks as a means of recovery for swimmers with disadaptation syndrome helped to optimize the biochemical status and cerebral circulation 20-min after warm-up. The reaction to the warm-up load under test conditions was characterized by increasing total blood filling of the brain and difficulty of venous outflow. Under the action of drugs, a decrease in blood filling of the brain and increase in venous blood outflow from the cerebral basin was observed 20 min after load in all test groups (except the hypokinetic group taking picamilon).

Effects of electrical and chemical stimulation of the amygdala on the spontaneous discharge in the insular cortex in rats

Both the amygdala (especially, the basolateral nucleus of the amygdala) and the insular cortex are important for conditioned taste aversion. From the anatomical view point, there are reciprocal connections between the insular cortex and the amygdala. In the present study, we investigated the effect of electrical and chemical stimulation of the amygdala on the spontaneous discharge of the insular cortex neurons in anesthetized rats. In most neurons (10 of 14), spontaneous discharge was decreased after a microinjection of glutamate (Glu). In these neurons, the injection site was within the basolateral nucleus of the amygdala (the basolateral/lateral nuclei). On the other hand, when a gamma amino-butyric acid (GABA) was microinjected into the basolateral nucleus of the amygdala, none of the 5 neurons showed any change in spontaneous discharge. Electrical train stimulation of the basolateral nucleus of the amygdala (100 Hz, 2-6 s) depressed the spontaneous discharge of the neurons in the insular cortex, as in the case of a Glu microinjection. These results indicate that activation of the basolateral nucleus of the amygdala could depress the neuronal activity in the insular cortex. Such results may yield data leading to the elucidation of the neuronal mechanisms of conditioned taste aversion.

Method for the construction and use of carbon fiber multibarrel electrodes for deep brain recordings in the alert animal

Microiontophoresis of neuroactive substances during single unit recording in awake behaving animals can significantly advance our understanding of neural circuit function. Here, we present a detailed description of a method for constructing carbon fiber multibarrel electrodes suitable for delivering drugs while simultaneously recording single unit activity from deep structures, including brainstem nuclei and the cerebellum, in the awake behaving primate. We provide data that should aid in minimizing barrel resistance and the time required to fill long, thin multibarrel electrodes with solutions. We also show successful single unit recording from a variety of areas in the awake squirrel monkey central nervous system, including the vestibular nuclei, Interstitial Nucleus of Cajal, and the cerebellum. Our descriptions and data should be useful for investigators wishing to perform single unit recordings during microiontophoresis of neuroactive substances, particularly in deep structures of animals with chronically implanted recording chambers.

Gamma-vinyl GABA inhibits cocaine-triggered reinstatement of drug-seeking behavior in rats by a non-dopaminergic mechanism

Relapse to drug use is a core feature of addiction. Previous studies demonstrate that gamma-vinyl GABA (GVG), an irreversible GABA transaminase inhibitor, attenuates the acute rewarding effects of cocaine and other addictive drugs. We here report that systemic administration of GVG (25-300 mg/kg) dose-dependently inhibits cocaine- or sucrose-induced reinstatement of reward-seeking behavior in rats. In vivo microdialysis data indicated that the same doses of GVG dose-dependently elevate extracellular GABA levels in the nucleus accumbens (NAc). However, GVG, when administered systemically or locally into the NAc, failed to inhibit either basal or cocaine-priming enhanced NAc dopamine in either naïve rats or cocaine extinction rats. These data suggest that: (1) GVG significantly inhibits cocaine- or sucrose-triggered reinstatement of reward-seeking behavior; and (2) a GABAergic-, but not dopaminergic-, dependent mechanism may underlie the antagonism by GVG of cocaine-triggered reinstatement of drug-seeking behavior, at least with respect to GVG's action on the NAc.

Valproic acid sodium inhibits the morphine-induced conditioned place preference in the central nervous system of rats

The present study was performed to investigate the effects of valproic acid sodium (VPA), a widely utilized antiepileptic drug, on the establishment of chronic morphine-induced conditioned place preference (CPP). The rat model of morphine-induced CPP was conditioned with alternating intracerebroventricular (i.c.v.) injections of morphine (60 microg/6 microl) and saline for 5 days. To investigate the influence of VPA on morphine-induced CPP, rats received chronic pretreatment of i.c.v. VPA (500 microg/rat) 10 min previous to the daily morphine injection. The results demonstrated that the morphine-induced CPP was significantly attenuated by VPA pretreatment, while the VPA itself could not induce any CPP or conditioned place aversion (CPA) effects. The results of the present study not only confirmed the reliability of establishing morphine-induced CPP model by i.c.v. injection, but also suggest that the antiepileptic drug VPA may be utilized as potential therapeutic medications for drug abuse in the future.

Comparative effects of nonselective and subtype-selective gamma-aminobutyric acidA receptor positive modulators in the rat-conditioned emotional response test

Benzodiazepine receptor anxiolytics show no selectivity between gamma-aminobutyric acid-A receptors containing alpha1, alpha2, alpha3 or alpha5 subunits. Pharmacological studies and data emerging from transgenic mouse models, however, predict that compounds with selective affinity and/or efficacy for gamma-aminobutyric acid-A receptor subtypes would have novel pharmacological profiles. Thus, the gamma-aminobutyric acid-A-alpha1 'affinity selective' drug zolpidem has a sedative-hypnotic profile, whereas L838,417, which has 'selective efficacy' for gamma-aminobutyric acid-A-alpha2, alpha3 and alpha5 receptors, has an anxiolytic-like profile. Here, we compare the nonselective benzodiazepine-site-positive modulators diazepam, lorazepam, midazolam, alprazolam and zopiclone with (i) gamma-aminobutyric acid-AA-alpha1 affinity selective compounds zolpidem and CL218,872 and (ii) L838,417, in the rat-conditioned emotional response test after systemic administration. Given the role of the basolateral amygdala in anxiety and the expression of alpha1, alpha2 and alpha3 subunits in this region, we also assessed the effects of bilateral infusion of L838,417 and midazolam directly into basolateral amygdala in the conditioned emotional response test. Nonselective modulators at low-moderate doses produced anxiolytic effects and sedation at higher doses. Zolpidem was inactive as an anxiolytic and engendered severe sedation, whereas CL218,872 produced an anxiolytic-like profile with minimal sedation. L838,417 produced an anxiolytic-like profile with no sedation, albeit producing behavioural disturbance at high doses. Infusion of midazolam and L838,417 into basolateral amygdala engendered anxiolytic-like effects, although both compounds were more effective after systemic injections, implicating additional brain sites in their anxiolytic-like actions after systemic administration. In conclusion, the diversity of effects of the compounds studied implicates both intrinsic efficacy and/or subtype selectivity as important determinants of anxiolytic-like effects in the rat-conditioned emotional response test.

Uptake and release of [(3)H]GABA in human dental pulp

The purpose of this study was to determine whether (a) an uptake system for gamma-aminobutyric acid (GABA) exists in human dental pulp, (b) GABA can be released from nerves in this tissue, and (c) GABA(B) autoreceptors modulate release of this transmitter. Segments of vital pulp were incubated in [(3)H]GABA (0.1-10 microM) for up to 120 min, washed, and the retained [(3)H] extracted and assayed. Some tissues were treated with GABA uptake inhibitors (nipecotic acid or NO-711) prior to incubation. At concentrations of 0.1 and 1.0 microM the uptake of [(3)H]GABA was saturated after 90 min of incubation. At 10 microM, at least two uptake compartments were apparent, and the amount of [(3)H]GABA retained was five-fold greater than 0.1 microM. The uptake inhibitors reduced [(3)H]GABA accumulation by more than 80%. In the release study, pulp was incubated in [(3)H]GABA (0.5 microM) for 90 min, and superfused with Krebs solution containing NO-711 (5 microM). Electrical stimulation increased the overflow of [(3)H]; a GABA(B) autoreceptor agonist (baclofen) inhibited, whilst an antagonist, Sch 50911, enhanced this release. The effects of baclofen were reversed by Sch 50911. These results imply that GABA can be taken up and bound firmly in compartments within human dental pulp, GABA can be released from isolated pulp segments by electrical stimulation, and this release is modulated by GABA(B) autoreceptors.

Opposite effects of low and high doses of the gastrin-releasing peptide receptor antagonist RC-3095 on memory consolidation in the hippocampus: possible involvement of the GABAergic system

Although the gastrin-releasing peptide receptor (GRPR) has recently emerged as a system importantly involved in regulating memory formation, the role of hippocampal GRPRs in memory remains controversial. The present study examined the effects of GRPR antagonism on memory consolidation in area CA1 of the hippocampus. Male Wistar rats received bilateral infusions of the GRPR antagonist [D-Tpi6, Leu13 psi(CH2NH)-Leu14] bombesin (6-14) (RC-3095; 1, 3, or 10 microg/side) into the dorsal hippocampus immediately after inhibitory avoidance (IA) training. RC-3095 at 1 microg impaired, whereas the dose of 10 microg enhanced, 24-h IA retention. A second experiment showed that the RC-3095-induced enhancement of memory consolidation was prevented by pretraining infusion of an otherwise ineffective dose of the gamma-aminobutyric acid type A (GABA(A)) receptor agonist muscimol. The results indicate that high doses of GRPR antagonists can induce enhancement of memory consolidation in the hippocampus. In addition, the memory-enhancing effect of GRPR antagonists might be mediated by inhibition of GABAergic transmission.

Enhancement of extinction memory consolidation: the role of the noradrenergic and GABAergic systems within the basolateral amygdala

Evidence from previous studies indicates that the noradrenergic and GABAergic influences within the basolateral amygdala (BLA) modulate the consolidation of memory for fear conditioning. The present experiments investigated whether the same modulatory influences are involved in regulating the extinction of fear-based learning. To investigate this issue, male Sprague Dawley rats implanted with unilateral or bilateral cannula aimed at the BLA were trained on a contextual fear conditioning (CFC) task and 24 and 48 h later were given extinction training. Immediately following each extinction session they received intra-BLA infusions of the GABAergic antagonist bicuculline (50 ng), the beta-adrenocepter antagonist propranolol (500 ng), bicuculline with propranolol, norepinephrine (NE) (0.3, 1.0, and 3.0 microg), the GABAergic agonist muscimol (125 ng), NE with muscimol or a control solution. To investigate the involvement of the dorsal hippocampus (DH) as a possible target of BLA activation during extinction, other animals were given infusions of muscimol (500 ng) via an ipsilateral cannula implanted in the DH. Bilateral BLA infusions of bicuculline significantly enhanced extinction, as did infusions into the right, but not left BLA. Propranolol infused into the right BLA together with bicuculline blocked the bicuculline-induced memory enhancement. Norepinephrine infused into the right BLA also enhanced extinction, and this effect was not blocked by co-infusions of muscimol. Additionally, muscimol infused into the DH did not attenuate the memory enhancing effects of norepinephrine infused into the BLA. These findings provide evidence that, as with original CFC learning, noradrenergic activation within the BLA modulates the consolidation of CFC extinction. The findings also suggest that the BLA influence on extinction is not mediated by an interaction with the dorsal hippocampus.

Pharmacotherapy of spasticity in children with cerebral palsy

Spasticity is one of the most common symptoms presented by neurologic patients. Apart from surgical management, drug therapy is an important treatment of children suffering from spasticity. In this review, recent advances in the pharmacologic armamentarium are reported in detail. In particular, there are oral medications (benzodiazepines, baclofen, dantrolene sodium, alpha 2 adrenergic agonists) and parenteral medications (botulinum toxin type A and B, alcohol). Moreover, there is also baclofen that can be administered intrathecally. There are some reports supporting the use of intramuscular alcohol (45% and/or 5-7% phenol) to reduce spasticity without the loss of voluntary movement or loss of sensation. Among these drugs, intrathecal baclofen is one of the most effective substances that can reduce spasticity significantly in the upper and lower extremities. Finally, the effectiveness of therapy with botulinum toxin type A in the management of spasticity is analyzed. Botulinum toxin type A reduces hypertonia in the injected muscles for a period of 2 to 4 months without important side effects. The purpose of this article is to provide an overview of available oral and parenteral drugs for treatment of spasticity in cerebral palsy and to outline indications and contraindications.

Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans

The effect of orally administrated gamma-aminobutyric acid (GABA) on relaxation and immunity during stress has been investigated in humans. Two studies were conducted. The first evaluated the effect of GABA intake by 13 subjects on their brain waves. Electroencephalograms (EEG) were obtained after 3 tests on each volunteer as follows: intake only water, GABA, or L-theanine. After 60 minutes of administration, GABA significantly increases alpha waves and decreases beta waves compared to water or L-theanine. These findings denote that GABA not only induces relaxation but also reduces anxiety. The second study was conducted to see the role of relaxant and anxiolytic effects of GABA intake on immunity in stressed volunteers. Eight acrophobic subjects were divided into 2 groups (placebo and GABA). All subjects were crossing a suspended bridge as a stressful stimulus. Immunoglobulin A (IgA) levels in their saliva were monitored during bridge crossing. Placebo group showed marked decrease of their IgA levels, while GABA group showed significantly higher levels. In conclusion, GABA could work effectively as a natural relaxant and its effects could be seen within 1 hour of its administration to induce relaxation and diminish anxiety. Moreover, GABA administration could enhance immunity under stress conditions.

Intravenous treatment of chronic daily headaches in the outpatient headache clinic

The most likely future of aggressive headache treatment will reside in the sphere of the specialist's clinic. This is a far more cost- and time-effective mode of treating intractable chronic daily headaches (CDH), including chronic migraines. We have used this technique successfully in our clinic for many years. Our experience with intravenous treatment of headaches and migraines was summarized recently and a 97.5% success rate for this type of treatment was found in the clinic. Compared with the treatments commonly available in the emergency department, the specialist's clinic can offer more effective headache-altering definitive treatments. Patients can be offered a maximum degree of success for control of their intractable headaches. In this article, approaches to aggressive treatment of ongoing CDH using intravenous methods of therapy are discussed. All of these can be performed in the clinic setting, avoiding some of the costly aspects of treatment that are present in an emergency room setting.

Intrahippocampal nicotine and neurosteroids effects on the anxiety-like behaviour in voluntary and chronic alcohol-drinking rats

Considerable evidence suggests that the anxiolytic effects of ethanol may be one of the factors that promotes alcohol consumption. The present study aimed to characterize the effects of intrahippocampal administrations of nicotine and the two neurosteroids pregnenolone sulphate (PregS) and allopregnanolone (AlloP) on anxiety-like behaviours in alcohol-drinking rats. A long-lasting free-choice drinking procedure with an early availability (from weaning) of an alcoholic solution (10% (v/v) ethanol, 3% (w/v) glucose in distilled water) was used. After 80 days of consumption, alcohol-drinking and control rats were deprived of food and assigned at random to six groups. After 100 days of consumption, each group received two consecutive intrahippocampal (dorsal CA1) injections. First injection: nicotine (4.6 microg, 20 mM) or saline; second injection: PregS (5 ng, 24 microM), AlloP (0.2 microg, 1.26 microM) or saline. Following the injections, novelty-directed activity (open field, OF), and motor coordination (80 degrees inclined screen) were tested. Blood alcohol concentrations (BACs) were assessed. Anxiolytic-like effects of voluntary ethanol consumption and intrahippocampal AlloP administration were observed. Alcohol intake increased the novelty-induced ambulation and exploration of central areas, and decreased defecation. The high exploration levels induced by AlloP decreased significantly over sessions, indicating a rapid habituation to the environmental conditions. Motor coordination was deteriorated by ethanol consumption. These results demonstrate the effects of chronic alcohol intake and neurosteroid administration on anxiety-related behaviours, and suggest an important role of the hippocampal GABA(A) receptor in these behaviours.

Effect of Divalproex on Metabolic Parameters Is Dose Related in Migraine Prophylaxis

OBJECTIVE

To examine the metabolic effects of three divalproex dosing regimens in patients with migraine.

BACKGROUND

Epidemiological and clinical studies have demonstrated a strong association between serum lipid levels and the development of coronary artery disease. Thus, it is important to understand the impact of chronically administered medications on serum lipids. Metabolic properties of divalproex, an approved and commonly used treatment for migraine prophylaxis, have not been systematically studied in patients with migraine.

METHODS

Adult patients with migraine were randomized to receive one of three daily doses of divalproex (500 mg [n = 45], 1000 mg [n = 43], or 1500 mg [n = 44]) or placebo (n = 44) for 12 weeks. Post hoc analyses were performed to determine the effects of divalproex on total cholesterol, glucose, weight, and body mass index (BMI).

RESULTS

The treatment groups were similar at baseline based on demographic and clinical characteristics and the use of concomitant medications. Divalproex resulted in a dose-related mean decrease from baseline in total cholesterol: -5.7 mg/dL or 3% reduction with 500 mg/day; -8.4 mg/dL or 4% reduction with 1000 mg/day; and -12.8 mg/dL or 7% reduction with 1500 mg/day (P < .05 for 1500 mg/day vs. placebo). There were no differences between any divalproex dose group and placebo for mean change from baseline in glucose, weight, or BMI.

CONCLUSIONS

Divalproex results in a dose-dependent reduction in serum cholesterol within the first 3 months of therapy, with no significant change in serum glucose or BMI.

Discriminative stimulus effects of 5.6 mg/kg pregnanolone in DBA/2J and C57BL/6J inbred mice

Neurosteroids represent a class of endogenous compounds that exert rapid, nongenomic effects through neurotransmitter receptor systems such as gamma-aminobutyric acid(A) (GABA(A)). Two neurosteroids, allopregnanolone (3alpha-hydroxy-5alpha-pregnan-20-one) and pregnanolone (3alpha-hydroxy-5beta-pregnan-20-one), possess anxiolytic and sedative properties and show substitution for ethanol, benzodiazepines, and barbiturates in drug discrimination assays. A previous study examining the discriminative stimulus effects of 10 mg/kg pregnanolone in DBA/2J and C57BL/6J mice showed pregnanolone's discriminative stimulus to be mediated primarily through GABA(A) positive modulation. This study examined the discriminative stimulus effects of a lower training dose (5.6 mg/kg) of pregnanolone in DBA/2J and C57BL/5J mice. Twelve male DBA/2J mice and 12 male C57BL/6J mice were trained to discriminate 5.6 mg/kg pregnanolone. GABA(A)-receptor positive modulators, neuroactive steroids, NMDA receptor antagonists, and 5-HT(3) receptor agonists were tested for pregnanolone substitution. In DBA/2J and C57BL/6J mice benzodiazepine, barbiturate, and GABAergic neuroactive steroids all substituted for pregnanolone. In the DBA/2J mice, NMDA receptor antagonists showed generalization to the discriminative stimulus cues of pregnanolone, an effect not seen in the C57BL/6J mice. 5-HT(3) receptor agonists and zolpidem failed to substitute for pregnanolone's discriminative stimulus in either strain. AlloTHDOC and midazolam were more potent in producing pregnanolone-like discriminative stimulus effects in DBA/2J mice. These results provide a comprehensive look at pregnanolone's discriminative stimulus effects in two commonly used strains of mice. The present data suggest GABA(A)-receptor positive modulation as the predominant receptor mechanism mediating the discriminative stimulus effects of pregnanolone. NMDA receptor antagonism was suggested in the DBA/2J mice and may represent a heterogenous cue produced by the lower training dose of pregnanolone.

Efficacy and Tolerability of Intravenous Valproic Acid in Acute Adolescent Migraine

OBJECTIVE

To describe the efficacy and tolerability of rapid intravenous valproic acid (VPA) infusions in children with severe migraine headache.

BACKGROUND

Intravenous VPA is an emerging treatment option for acute migraine headache. Adult data suggests both efficacy and tolerability of rapid VPA infusions as abortive therapy, but little data exist in children.

METHODS

We conducted a retrospective chart review of all children who received intravenous VPA at The Children's Hospital Headache Clinic during an 18--month study period. Baseline intensity of headache pain, time at which maximum relief was attained, pain reduction following therapy, dose and duration of VPA infusion(s), patient's pulse, blood pressure, respiratory rate, and pulse oximetry were collected. Adverse events were also recorded.

RESULTS

Thirty-one children (age=15+/- 2 years; 81% female) requiring 58 clinic visits and 71 VPA infusions were included. Most visits (n=45; 78%) resulted in only one dose of VPA (976+/- 85 mg infused over 12+/- 4 minutes) for desired pain relief. Percent pain reduction in those children was 39.8%, with time to maximum relief of 63+/- 31 minutes. Some children required a second dose of 500 mg (n=13 visits; 22%), that was infused over 14+/- 6 minutes and produced a 57% reduction in pain intensity from baseline. VPA infusions were well tolerated. Adverse events described included cold sensation (1), dizziness (3), nausea (1), possible absence seizure (1), paraesthesia (2), and tachycardia (2).

CONCLUSIONS

Rapid infusion of intravenous VPA is generally well tolerated and may play a role in the management of children with acute migraine headache. Prospective, controlled trials to further investigate this treatment in children are warranted.

Comparison of intravenous valproate with intravenous lysine-acetylsalicylic acid in acute migraine attacks

OBJECTIVE

The study compared efficacy and tolerability of intravenous valproate (iVPA) with intravenous lysine-acetylsalicylic acid (iLAS) in acute migraine attacks. Background.-iLAS has been proven to be a highly effective treatment in acute migraine attacks, but it is not available in many countries and contraindicated in patients with asthma or peptic ulcers. Current data suggest that iVPA may be effective in the treatment of acute migraine attacks.

DESIGN/METHODS

In this randomized, double-blind, parallel-group phase-II study, 40 patients with acute migraine attacks (onset <5 hours, severe or moderate headache on a four-point IHS scale) alternately received iVPA 800 mg or iLAS 1000 mg. Primary outcome criteria were the percentage of patients reporting pain relief after 1 hour and patients who remained sustained pain free for 24 hours following drug administration. Secondary outcome criteria were relief of pain and associated migrainous symptoms (nausea, photophobia, and phonophobia) at 1, 2, 24, and 48 hours following drug administration.

RESULTS

There were no significant differences in demographic and clinical features between both treatment groups. Percentage of pain relief after 1 hour in the iVPA and iLAS groups were 25% and 30%, respectively, and of sustained pain free for 24 hours were 20% and 30%, respectively, without significant differences (P = 1 and P= .72, respectively). Both drugs improved associated migrainous symptoms without significant differences at the different time points, but again with a trend in favor of iLAS. No adverse events were observed.

CONCLUSION

Both drugs were effective in acute migraine attacks with a trend in favor of iLAS. As both drugs were well tolerated, further studies with higher doses of iVPA for the treatment of acute migraine attacks are recommended.

GABA and glutamate systems as therapeutic targets in depression and mood disorders

Advances made in diverse areas of neuroscience suggest that neurotransmitter systems, additional to the monoaminergic, contribute to the pathophysiology of mood disorders. This ever accruing body of preclinical and clinical research is providing increased recognition of the contribution made by amino acid neurotransmitters to the neurobiology of mood disorders. This review examines evidence supporting the role of GABA and glutamate in these processes and explores the potential to target these systems in the development of novel compounds; the viability of these agents for treatment-related co-morbidities will also be considered.

Effects of injecting GABAergic agents into the medullary reticular formation upon swallowing induced by the superior laryngeal nerve stimulation in decerebrate cats

The purpose of this study was to elucidate the role of the GABAergic system in the medullary reticular formation (MRF) in the control of swallowing. In acutely decerebrated cats (n = 12), swallowing was induced by electrical stimulation (0.3-6 V at 10-20 Hz for 10-20 s every minute) applied to the superior laryngeal nerve (SLN). The stimulus intensity was adjusted so that swallowing was induced two or four times during the period of the stimulation. Bicuculline, a GABA(A) receptor antagonist, was then injected (0.10-0.15 microl, 5 mM) into the MRF through a stereotaxically placed glass micropipette. In a total of 62 injections, 19 injections (30.6%) increased the frequency of SLN-induced swallowing when it was injected into the lateral part of the MRF corresponding to the nucleus reticularis parvocellularis (NRPv). In eight of the effective injections (42.1%) which increased the frequency of SLN-induced swallowing, SLN stimulation also induced coughing. With two injections, stimulation of the SLN-induced coughing but not facilitation of swallowing. On the other hand, an injection of 0.10-0.15 microl of 5 mM muscimol, a GABA(A) receptor agonist, into the NRPv decreased the frequency of SLN-induced swallowing. These results suggest that the NRPv neurons which are responsible for evoking swallowing are under the tonic inhibitory control of the GABAergic system.

[Effect of the GABA derivative phenibut on learning]

The learning effect of phenibut, a beta-phenyl derivative of the inhibitory neuromediator GABA, used in a subcutaneous dose of 40 mg/kg 2 hours before each experiment, was studied in rabbits. The injection of phenibut was shown to enhance not only the inhibitory, but also excitatory components of cerebral cortical neuronal responses to all applied stimuli. The findings support the concept that the GABAergic neuromediator system is involved in the elaboration of internal inhibition and explain the sense of intracerebral processes that ensure both the sedative properties of phenibut and its ability to improve patients' systemic tone and health status when brain dysfunctions are treated.

Ethosuximide and valproate display high efficacy against lindane-induced seizures in mice

Both lindane (gamma-hexachlorocyclohexane), an organochlorine ectoparasiticide and pentylenetetrazol, used as a model of experimental epilepsy, produce convulsive seizures resulting from the blockade of the gamma-aminobutyric acid (GABAA) receptor. In the present study we established the protective effects of ethosuximide and valproate against seizures induced by lindane and compared them with the well-known protective effects of these drugs against pentylenetetrazol-induced seizures in mice. Both ethosuximide and valproate afforded complete and dose-dependent protection against seizures induced by lindane. However, the potencies of these drugs were lower than those obtained against pentylenetetrazol seizures. Nevertheless, the protective efficacy of ethosuximide and valproate against experimentally induced lindane seizures may suggest possible efficacy of these drugs against seizures in lindane-poisoned patients.

Pharmacotherapy for Marijuana Dependence: A Double-blind, Placebo-controlled Pilot Study of Divalproex Sodium

There is a noticeable lack of targeted treatment options for marijuana dependence, in particular pharmacologic approaches. This is the first study evaluating a targeted pharmacologic approach for marijuana dependence. The goals of the study were to determine if such patients would seek pharmacologic treatment, whether these patients could be retained in treatment using a design previously developed for cocaine-dependent patients, and especially whether divalproex sodium showed promise as a treatment agent for marijuana dependence. We found that marijuana-dependent patients will seek treatment, and such patients can be adequately maintained in a pharmacologic trial. Regardless of treatment group, patients reported a significant reduction in their frequency and amount of marijuana use as well as a reduction in irritability. Given the lack of proven effective treatments for marijuana dependence, pharmacotherapies should be sought. The design of a preliminary clinical trial should include a psychosocial/behavioral intervention emphasizing motivation and medication compliance and a placebo control group.

Brainstorms: symptoms and circuits, part 2: anxiety disorders

Numerous anxiety disorders may have malfunctioning neuronal circuits in common, which may account for the overlapping symptoms and frequent comorbidity of many anxiety disorders with one another.

Tiagabine increases cocaine-free urines in cocaine-dependent methadone-treated patients: results of a randomized pilot study

AIMS

We sought to evaluate the safety and efficacy of the GABAergic agent tiagabine in reducing cocaine use among methadone-treated patients.

DESIGN

Ten-week randomized double-blind placebo-controlled trial.

SETTING

Opiate Treatment Research Program, Veteran's Affairs Connecticut Healthcare System in West Haven, Connecticut, USA.

PARTICIPANTS

The participants were 45 cocaine-dependent methadone-treated patients who were predominately Caucasian (75.6%), male (77.8%) and never married (53%) with an average age of 38 years (SD = 6.5).

INTERVENTIONS

Comparison groups received tiagabine 12 mg/day (n = 15), tiagabine 24 mg/day (n = 15) or placebo (n = 15).

MEASURES

Baseline assessments included the Structured Clinical Interview for DSM-IV, the Addiction Severity Index, a urine drug test, self-reported use and opiate withdrawal scales. Urine drug tests were performed thrice weekly.

FINDINGS

Treatment retention was over 80% for all treatment groups. The sample mean (+/- SE) of cocaine-free urines for the first week after study entry and before tiagabine was started was 1.16 (0.19) urines/week. During weeks 9 and 10 cocaine-free urines increased significantly from baseline by 33% with high-dose tiagabine (24 mg/day), by 14% with low-dose tiagabine (12 mg/day) and decreased by 10% with placebo (hierarchical linear model, Z= 2.03; P < 0.05). Self-reported cocaine use also decreased significantly more with active medications than with placebo.

CONCLUSIONS

Tiagabine at 24 mg/day was well tolerated among these methadone-treated patients with only one reporting headache. Tiagabine appears to be a promising GABAergic medication that moderately improves cocaine-free urines.

[Influence of ivadal and depakene chrono on sleep structure in patients with epilepsy]

Because of strong association between epilepsy mechanisms and sleep disturbances, the latter may deteriorate the disease course and the patient's quality of life. Thirty eight patients with epilepsy (19 men and 19 women, mean age 25.6 +/- 11.4 years, age at onset 19.1 +/- 13.3 years, the disease duration 7.2 +/- 6.9 years) have been examined. The control group included 10 healthy individuals. The comparative group comprised 17 patients with physiological insomnia. All the patients had sleep disturbances of different level and were given hypnotic drug ivadal, which was compared to anticonvulsant depakine chrono, directly influencing GABA-ergic brain system. After sleep corrections, positive clinical and electroencephalographic trends in epileptic patients were detected. Comparing to depakine chrono, ivadal was suggested to up-regulate GABA-ergic brain systems during sleep due to rehabilitation of physiological brain characteristics.

Effects of intrahippocampal injection of GABAergic drugs on memory retention of passive avoidance learning in rats

The effect of post-training intrahippocampal injection of gamma-aminobutyric acid (GABA) receptor agonists and antagonists, immediately after a training session on memory retention of passive avoidance learning in rats, was measured in the presence and absence of physostigmine. Post-training treatments were carried out in all the experiments. The different doses of the GABAA receptor agonist muscimol (2, 4 and 6 microg/rat) decreased memory retention in rats dose-dependently. The higher response was obtained with 6 microg/rat of the drug. When the GABAA receptor antagonist bicuculline (0.5, 1, 2 and 4 microg/rat) was administered, only one dose of the drug (1 microg/rat) increased memory retention; however, the antagonist reduced the effect of muscimol. The GABAB receptor agonist, baclofen (0.25, 0.5, 1 and 2 microg/rat) also reduced memory retention in the animals. Intrahippocampal injection of lower doses of the GABAB receptor antagonist CGP35348 (P-[3-aminopropyl]-p-diethoxymethyl-phosphinic acid) (2.5, 5, 10 microg/rat) did not effect memory retention, although the higher doses of the drug (25 and 50 microg/rat) decreased memory retention. The doses of antagonist (2.5, 5 and 10 microg/rat), which did not elicit any response alone, reduced the effect of baclofen. The inhibitory response of CGP35348 was also decreased by bicuculline. In another series of experiments, physostigmine improved memory retention. The GABA receptor agonists, muscimol and baclofen, as well as the GABA receptor antagonists bicuculline and CGP35348, decreased the effect of physostigmine. Atropine decreased memory retention by itself and potentiated the response of muscimol and baclofen. It is concluded that GABAA and GABAB receptor activation may be involved in the impairment of memory retention.

Valproate prevents the induction and the expression of MK-801 sensitization

Repeated administration of psychostimulants such as amphetamine, cocaine, and methylphenidate has been shown to induce behavioral sensitization. Sodium valproate, an anticonvulsant agent that enhances GABA activity, and dizocilpine (MK-801), a non-competitive NMDA receptor antagonist, can block the sensitization elicited by psychostimulants. MK-801 also has been demonstrated to sensitize to itself. The objective of the present study was to determine whether valproate disrupts the behavioral sensitization elicited by MK-801. Male Sprague-Dawley rats were given a regimen of repeated MK-801 injections (0.3 mg/kg, i.p.) that produced behavioral sensitization. They were also given valproate, at a dosage (50 mg/kg, i.p.) that prevented behavioral sensitization to stimulants, either during or after multiple MK-801 injections. After the washout period, animals were then re-challenged with MK-801 to determine whether valproate disrupted the behavioral sensitization elicited by MK-801. An activity monitoring system recorded horizontal activity, total distance, and vertical activity of the animals following drug treatment. Results of their locomotor responses demonstrated that valproate disrupted the development/induction and the expression of sensitization to MK-801, as it did to methylphenidate.

A randomized trial of divalproex sodium extended-release tablets in migraine prophylaxis

OBJECTIVE

To evaluate the efficacy and safety of extended-release divalproex sodium compared with placebo in prophylactic monotherapy treatment of migraine headache.

METHODS

This was a double-blind, randomized, placebo-controlled, parallel-group study. Subjects with more than two migraine headache attacks during a 4-week baseline were randomly assigned in a 1:1 ratio at each center to receive either extended-release divalproex sodium or matching placebo once daily for 12 weeks. Subjects initiated treatment on 500 mg once daily for 1 week, and the dose was then increased to 1,000 mg once daily with an option, if intolerance occurred, to permanently decrease the dose to 500 mg during the second week. Reduction from baseline in 4-week migraine headache rate was the primary efficacy variable. Migraine headaches separated by a < 24-hour headache-free interval were counted as single migraines in calculating migraine headache rates. Tolerance and safety were also evaluated.

RESULTS

The mean reductions in 4-week migraine headache rate were 1.2 (from a baseline mean of 4.4) in the extended-release divalproex sodium group and 0.6 (from a baseline mean of 4.2) in the placebo group (p = 0.006); reductions with extended-release divalproex sodium were significantly greater than with placebo in all three 4-week segments of the treatment period. No significant differences were detected between treatment groups in either the overall incidence or in the incidence of any specific treatment-emergent adverse event; 8% of subjects treated with extended-release divalproex sodium and 9% of those treated with placebo discontinued for adverse events.

CONCLUSION

Extended-release divalproex sodium is an efficacious, well-tolerated, safe, and easy-to-use once-a-day prophylactic antimigraine medication.

Sydenham's chorea: clinical findings and comparison of the efficacies of sodium valproate and carbamazepine regimens

BACKGROUND

Sydenham's chorea is still the most frequently seen form of acquired chorea in childhood in developing world despite the use of antibiotics. It is a debilitating illness lasting for weeks or months and requires drug therapy.

OBJECTIVE

To evaluate and compare the efficacies of sodium valproate and carbamazepine in the treatment of the choreiform movements in Sydenham's chorea.

DESIGN

A prospective trial carried out with 24 children with Sydenham's chorea.

PATIENTS

Twenty-four patients were divided into two groups having similar demographic and clinical properties. One group (n = 17) was given carbamazepine (15 mg/kg per day) and the other (n = 7) was given sodium valproate (20-25 mg/kg per day). As soon as the symptoms were taken under control, doses of the drugs were tapered slowly. The duration of the drug use was recorded. The time of response to therapy was compared between the groups and the patients were monitored for the adverse effects.

RESULTS

There was no significant difference between the groups with respect to the time of clinical improvement and time of complete remission, duration of the therapy and the recurrence rates. Clinical improvement began by 8.0 +/- 4.0 days in sodium valproate and 7.4 +/- 8.2 days in carbamazepine group (P = 0.88). In the whole group no adverse effect was seen due to the drugs.

CONCLUSION

Carbamazepine and valproic acid are equally effective and safe drugs in the treatment of choreiform movements in Sydenham chorea.

Effect of intracerebroventricular injection of GABA receptor agents on morphine-induced antinociception in the formalin test

In the present study, the effects of gamma-aminobutyric acid (GABA) receptor agonists and antagonists on antinociception induced by morphine in the formalin test were investigated in rats. Intraperitoneal (i.p.) injection of different doses of morphine (1, 3, 6 and 9 mg/kg) and intracerebroventricular (i.c.v.) injection of different doses of muscimol (0.5, 1 and 2 microg per rat) or baclofen (0.25, 0.5 and 1 microg per rat) induced a dose-related antinociception in the both first and second phases of the formalin test. The responses induced by muscimol or baclofen in both phases were reduced by bicuculline or CGP35348 [p-(3-aminopropyl)-p-diethoxymethyl-phosphinic acid], respectively. Bicuculline alone has produced antinociception in the second phase and CGP35348 alone has had antinociception in both phases of the formalin test. Morphine in combination with different doses of muscimol or baclofen did not elicit potentiation. The opioid receptor antagonist naloxone reduced the response induced by muscimol in the second phase and baclofen in both phases of the formalin test. It may be concluded that central GABA(A) and GABA(B) receptor stimulation induces antinociception in the formalin test. However, the antinociception induced by GABA receptor agonists may be mediated partly through supraspinal opioid receptor mechanisms and, for the GABA(B) receptor agonist, through spinal and supraspinal opioid receptor mechanisms.

[Treatment of idiopathic headache in childhood - recommendations of the German Migraine and Headache Society (DMKG)]

According to the principles of evidence-based medicine, the controlled studies on the treatment of idiopathic headache in childhood have been analysed and compiled to treatment recommendations. For the acute treatment of migraine attacks or tension-type headache, ibuprofen (10 mg per kg body weight) or acetaminophen (15 mg per kg body weight) are recommended with highest evidence, intranasal sumatriptan (10 to 20 mg) can be given as second choice. For the prophylaxis of migraine, betablockers (propranolol and metoprolol), flunarizine, and valproic acid are recommended. Flunarizine is the drug of first choice in the treatment of migraine-related disorders. No controlled studies are available for the treatment of further headache types. First line methods for the non-drug treatment of headache in childhood are relaxation therapies, biofeedback, and specific training schedules.

GABAA-benzodiazepine-chloride receptor-targeted therapy for tinnitus control: preliminary report

Our goal was to attempt to establish neuropharmacological tinnitus control (i.e., relief) with medication directed to restoration of a deficiency in the gamma-aminobutyric acid-benzodiazepine-chloride receptor in tinnitus patients with a diagnosis of a predominantly central type tinnitus. Thirty tinnitus patients completed a medical audiological tinnitus patient protocol and brain magnetic resonance imaging and single-photon emission computed tomography of brain. Treatment with GABAergic and benzodiazepine medication continued for 4-6 weeks. A maintenance dose was continued when tinnitus control was positive. Intake and outcome questionnaires were completed. Of 30 patients, 21 completed the trial (70%). Tinnitus control lasting from 4-6 weeks to 3 years was reported by 19 of the 21 (90%). The trial was not completed by 9 of the 30 (30%). No patient experienced an increase in tinnitus intensity or annoyance. Sequential brain single-photon emission computed tomography in 10 patients revealed objective evidence of increased brain perfusion. Patients with a predominantly central type tinnitus experience significant tinnitus control with medication directed to the gamma-aminobutyric acid-benzodiazepine-chloride receptor.

Behavioral analysis indicates benzodiazepine-tolerance mediated by the benzodiazepine binding-site at the GABA(A)-receptor

1. GABA(A)-receptor induced changes in locomotion and anxiety-like behaviors were studied in rats using an open-field and an elevated plus-maze. Acute and chronic doses of the benzodiazepine diazepam without and in combination with the GABA uptake inhibitor SKF-89976A were investigated. 2. Fifty-six male rats of the strain PVG/OlaHsd (PVG; 180-200 g body wt) were used to assess the influence of the benzodiazepine binding-site to the development of tolerance. Rats were divided into six groups: The first receiving saline (0.9%), the second and third diazepam (10.0 mg/kg) daily for 23 days with or without an acute challenge of 2.0 mg/kg diazepam. The fourth group received diazepam (10.0 mg/kg) daily and acutely SKF-89976A (15.0 mg/kg) plus diazepam and the fifth and sixth group received acute treatment with diazepam (2.0 mg/kg) or SKF-89976A (15.0 mg/kg). 3. Under chronic treatment with diazepam the animals became tolerant to acute doses of diazepam in activity and anxiety-related behaviors. Acute treatment with SKF-89976A increased exploration. Parameters expressing anxiolytic-like behaviors were increased, too, but not all of them significantly. In diazepam tolerant animals SKF-89976A produced anxiolytic-like behaviors 4. We conclude that the BZ- and not the GABA-binding site at the GABA(A)-receptor is involved in the development of BZ-tolerance.

Divalproex loading in the treatment of cocaine dependence

The current pilot project was designed to evaluate the safety and tolerability of a loading dose of divalproex (DVPX) in subjects with cocaine dependence. Seventeen cocaine-dependent subjects were enrolled in an eight-week, open-label trial of 20 mg/kg/day DVPX. Subjects were seen weekly and urine drug screens were obtained at each visit. Over the eight-week trial, craving intensity and frequency as well as reported time using cocaine decreased significantly. Retention in the current study was 79% at week four and 50% at week eight. The medication and dosing strategy was well tolerated. This pilot study indicates that DVPX loading is well tolerated and may be efficacious in the treatment of cocaine dependence. A placebo-controlled trial would be of interest.

Chronic exercise alters caudal hypothalamic regulation of the cardiovascular system in hypertensive rats

Previous studies have documented a deficit in the GABA neurotransmitter system within the caudal hypothalamus (CH) of spontaneously hypertensive rats (SHR). The reduction in inhibitory influence on this cardiovascular excitatory brain region is associated with an increased neuronal activity and resting blood pressure. The purpose of this study was to determine if chronic treadmill and wheel-running activities alter the ability of the CH to regulate cardiovascular function. SHR were exercised on a treadmill (5 times/wk) at moderate intensity or allowed free access to running wheels (7 days/wk) for a period of 10 wk. Resting blood pressures were obtained before and after the exercise training periods. After the exercise period, rats were anesthetized and microinjection experiments were performed. Treadmill-trained SHR exhibited a significantly blunted developmental rise in resting blood pressure after 10 wk of exercise. A similar yet less marked effect was observed in wheel-run rats. Microinjection of the GABA synthesis inhibitor 3-mercaptopropionic acid (3-MP) into the CH of nonexercised SHR did not produce any change in arterial pressure. In contrast, microinjection of 3-MP into the CH produced significant increases in blood pressure and heart rate in exercised SHR. These results demonstrate that exercise training can alter CH cardiovascular regulation in hypertensive rats and therefore may play a role in increasing cardiovascular health.

[Effect prolonged GABAergic activation on the pubertal development of female rats]

We evaluated, in immature female rats, the effect of the GABAergic system on the reproductive axis and on pubertal development. Initially, using a prolonged treatment with aminooxyacetic acid (AOAA), increasing hypothalamic GABA (p < 0.002), and decreasing GnRH and glutamate content (p < 0.05 and < 0.02). Treated rats showed diminished serum LH (p < 0.05) and estradiol (p < 0.005) levels. Vaginal opening occurred at 30.8 +/- 0.6 days in controls, and at 36.7 +/- 0.98 days in AOAA-treated rats. Acute treatment with AOAA resulted in a decreased GnRH and glutamate output, and in an increased taurine release from superfused hypothalamic fragments. This effect was mimicked by the GABA-A and GABA-B agonists. The activation of the GABAergic system during postnatal days 23-29 significantly restrains the hypothalamo-pituitary-ovaric axis and delays the onset of puberty. The existence of a physiological cross-talk between excitatory and inhibitory amino acid neurotransmitters regulating GnRH release during the onset of puberty is postulated.

GABA levels within the medial preoptic area: effects of chronic administration of sodium valproic acid

Sodium valproic acid (VPA) is a widely prescribed anticonvulsant medication that has been shown to interfere with pubertal maturation of the reproductive system, and induce endocrine abnormalities in adults, within a subset of the clinical population. While VPA's mechanism of action is still poorly understood, it may exert its anti-reproductive effects by enhancing GABAergic inhibition of the GnRH neuronal population within the medial preoptic area (mPOA). The purpose of this study was to determine if chronic administration of VPA alters GABA levels within the mPOA region. In Experiment 1, the mPOA, caudate, and arcuate nucleus regions were harvested from VPA-treated and control mice. Analysis of whole tissue content of GABA revealed that levels were lower in the caudate and arcuate nucleus regions of VPA-treated animals, whereas there were no group differences for the mPOA region. Collapsing across drug group, there was also a trend for males having overall higher levels of GABA as compared to females. In Experiments 2 and 3, mice were implanted with microdialysis probes within the mPOA region and sampled for extracellular GABA levels. Females (Exp. 3) were sampled either on diestrous, proestrous, or estrous. Results from males (Exp. 2) revealed that VPA enhanced extracellular GABA levels in the mPOA region compared with controls. However, GABA levels for both groups remained stable across the sampling period. Conversely, in Exp. 3, females showed cyclical release of GABA across the sampling period. For control females, GABA levels increased during the afternoon on all cycle days, but the rise on proestrus was smaller than on other cycle days. VPA-treated animals showed an overall reduction in GABA levels compared with controls. Furthermore, while GABA increased over sampling time on estrus and diestrus days of the cycle, there was not a significant rise in GABA on proestrus. These data indicate: (1) regional specificity in VPA effects upon GABA levels, (2) a sex difference in the effects of VPA on GABA levels within the mPOA, and (3) GABA levels increase on the afternoon of all days of the estrous cycle with VPA attenuating the rise seen on the afternoon of proestrus. These results provide evidence that VPA effects upon the reproductive axis may involve changes in GABA release, and that males and females show different patterns of neurochemical response to the drug.