A genetic study of the FMR1 gene in a Sardinian multiple sclerosis population

Multiple sclerosis (MS) is a complex autoimmune disease originated from the interplay between genetic and environmental factors. An overlap of clinical and neuroradiological parameters has been described between MS and an adult-onset neurodegenerative disorder, the fragile-X-associated tremor/ataxia syndrome (FXTAS). This syndrome is caused by a trinucleotide premutation expansion of a CGG sequence in the 55-200 repeat range, which is located in the fragile-X mental retardation 1 (FMR1) gene. Female premutation carriers have an increased propensity for immune-mediated disorders. Recently, a case of co-occurrence of MS and FXTAS was reported. Assuming that the premutation expansion may play a role in the MS susceptibility, we evaluated its frequency in a cohort of MS patients from Sardinia, an island characterized by a very high frequency of MS. Nuclear DNA was extracted by standard methods, purified with bisulfite treatment and then amplified twice by PCR with specific primers. Microsatellite analysis was performed and emizogotic subjects were sequenced. Clinical data of patients were also collected. Only 1/755 MS patients exhibited the premutation expansion with a heterozygosis pattern (30/58). No pathogenic repeat expansions (>200 repeats) were found in the entire cohort. Repeats labeled as the gray zone (45-60 repeats) were observed in 15/755 patients. No specific clinical features concerning disease course, disease activity, and disability were reported for these patients. Our results do not support a possible role for premutation or gray zone alleles in MS Sardinian patients. Further studies are needed to better understand the relationship between FXTAS and MS.

Genetic counselling in ALS: facts, uncertainties and clinical suggestions

The clinical approach to patients with amyotrophic lateral sclerosis (ALS) has been largely modified by the identification of novel genes, the detection of gene mutations in apparently sporadic patients, and the discovery of the strict genetic and clinical relation between ALS and frontotemporal dementia (FTD). As a consequence, clinicians are increasingly facing the dilemma on how to handle genetic counselling and testing both for ALS patients and their relatives. On the basis of existing literature on genetics of ALS and of other late-onset life-threatening disorders, we propose clinical suggestions to enable neurologists to provide optimal clinical and genetic counselling to patients and families. Genetic testing should be offered to ALS patients who have a first-degree or second-degree relative with ALS, FTD or both, and should be discussed with, but not offered to, all other ALS patients, with special emphasis on its major uncertainties. Presently, genetic testing should not be proposed to asymptomatic at-risk subjects, unless they request it or are enrolled in research programmes. Genetic counselling in ALS should take into account the uncertainties about the pathogenicity and penetrance of some genetic mutations; the possible presence of mutations of different genes in the same individual; the poor genotypic/phenotypic correlation in most ALS genes; and the phenotypic pleiotropy of some genes. Though psychological, social and ethical implications of genetic testing are still relatively unexplored in ALS, we recommend multidisciplinary counselling that addresses all relevant issues, including disclosure of tests results to family members and the risk for genetic discrimination.

[Cancer risk among shift workers: a review]

INTRODUCTION

According to IARC, shift work resulting in disruption of circadian rhythm is a probable human carcinogen (Group 2A).

METHODS

We examined the scientific literature on the carcinogenic risk among shift workers for risk assessment purposes.

RESULTS

Clock genes polymorphisms might contribute with suppression of melatonin synthesis, immuno-suppression from sleep deprivation, individual habits associated with shift work, and low vitamin D levels, in increasing risk of breast cancer, prostate cancer and lymphoma among shift workers.

CONCLUSION

Although the epidemiological evidence seems scanty, the hypothesis that shift work-related sleep deprivation would contribute to increasing cancer risk seems based on solid ground.

Behavioral, neuropsychiatric and cognitive disorders in Parkinson's disease patients with and without motor complications

BACKGROUND

Parkinson's disease (PD), commonly defined as a hypokinetic movement disorder, is hampered by the appearance of motor complications (MC), including dyskinesias and motor fluctuations, and non-motor symptoms such as behavioral, neuropsychiatric and cognitive disorders, which, in the last years, are gaining increasing attention. The factors affecting MC and these non-motor symptoms are still largely unknown and their interactions are not yet fully evaluated.

OBJECTIVE

To identify the presence of behavioral, neuropsychiatric and cognitive disorders in PD patients with and without MC and to evaluate their association with MC.

METHODS

Consecutive PD patients received a comprehensive structured clinical evaluation including pharmacologic treatment, MC and non-motor symptoms such as reward-seeking behaviors, neuropsychiatric symptoms (depression, anxiety, psychoses and hallucinations) and dementia.

RESULTS

349 patients were included in this analysis. Patient with MC showed enhanced frequency of dementia (p < 0.001), anxiety, depression and psychoses (p < 0.01). A higher frequency of impulse control disorders was detected in patients with dyskinesias (22.2% - p < 0.001) and motor complications (12.2% - p < 0.05). Dyskinesias were significantly more present in patients with hypersexuality (p < 0.05) and compulsive shopping (p < 0.001), while they were not significantly associated with pathological gambling and binge eating. Patients with dyskinesias also had significantly higher frequency of dopamine dysregulation syndrome, hallucinations and delusions (p < 0.001), with the exception of delusional jealousy.

DISCUSSION

We found a higher frequency of behavioral, neuropsychiatric and cognitive disorders in patients with MC. The lack of detection of dyskinesias in several PD patients with pathological gambling in our study represents a very interesting issue. While binge eating mainly seems to be related to the use of dopamine agonists, the significant lack of association between dyskinesias and delusional jealousy suggests the hypothesis of a possible underlying psychopathological predisposition rather than a mere pharmacologic effect in PD patients with these behavioral complications.

Defective cerebral gamma-aminobutyric acid-A receptor density in patients with systemic lupus erythematosus and central nervous system involvement. An observational study

Gamma-aminobutyric acid-A (GABA-A) receptors play a crucial role in regulating neuronal excitability and cognitive functions. Single-photon emission computerized tomography (SPECT) analysis of GABA-A receptors binding by 123I-labelled Iomazenil (123I-IMZ) has been applied in some neuropsychiatric disorders to investigate conditions where GABA-A receptor density can be detected in several pathophysiological conditions. In this study we investigate cerebral GABA-A receptor density in a small series of patients with systemic lupus erythematosus (SLE) and cognitive impairment characterized by recurrent, episodic memory loss. Nine female patients with SLE and cognitive alterations underwent to a clinical neuropsychiatric evaluation including digital video-EEG, brain MRI, 99mTc-ECD brain SPECT and 123I-IMZ brain SPECT. All patients tested showed diffuse or focal GABA-A receptor density reduction. This is, to our knowledge, the first report on GABA-A receptor density abnormalities associated with cognitive defects in SLE patients. We hypothesize that in our series a decrease in GABA-A receptor density might be related to the neurological manifestations. Further studies are needed to clarify this aspect and the possible mechanisms. GABA-A receptor density impairment might be due to the SLE-related cerebral vasculopathy, or to neuronal-reacting auto-antibodies or drugs which could interfere with GABA-A receptors expression/binding. This study may support the concept that cognitive impairment in systemic lupus erythematosus could be the outcome of fine-tuned neurotransmission alterations.

Vagal nerve stimulation improves cerebellar tremor and dysphagia in multiple sclerosis

Vagus nerve stimulation (VNS), an adjunctive approach for the treatment of epilepsy, was performed in three multiple sclerosis (MS) patients displaying postural cerebellar tremor (PCT) and dysphagia. Following VNS, improvement of PCT and dysphagia was manifested over a period of two and three months, respectively. In view of the involvement of the main brainstem visceral component of the vagus, the nucleus tractus solitarius (NTS), in modulating central pattern generators (CPGs) linked to both olive complex pathway and swallowing, improvement is likely to be VNS related. The results obtained suggest an additional therapeutic application for VNS and may represent a novel form of treatment in patients with severe MS.

Increase in 20–50Hz (gamma frequencies) power spectrum and synchronization after chronic vagal nerve stimulation

OBJECTIVE

Though vagus nerve stimulation (VNS) is an important option in pharmaco-resistant epilepsy, its mechanism of action remains unclear. The observation that VNS desynchronised the EEG activity in animals suggested that this mechanism could be involved in VNS antiepileptic effects in humans. Indeed VNS decreases spiking bursts, whereas its effects on the EEG background remain uncertain. The objective of the present study is to investigate how VNS affects local and inter regional syncronization in different frequencies in pharmaco-resistant partial epilepsy.

METHODS

Digital recordings acquired in 11 epileptic subjects 1 year and 1 week before VNS surgery were compared with that obtained 1 month and 1 year after VNS activation. Power spectrum and synchronization were then analyzed and compared with an epileptic group of 10 patients treated with AEDs only.

RESULTS

VNS decreases the synchronization of theta frequencies (P < 0.01), whereas it increases gamma power spectrum and synchronization (< 0.001 and 0.01, respectively).

CONCLUSIONS

The reduction of theta frequencies and the increase in power spectrum and synchronization of gamma bands can be related to VNS anticonvulsant mechanism. In addition, gamma modulation could also play a seizure-independent role in improving attentional performances.

SIGNIFICANCE

These results suggest that some antiepileptic mechanisms affected by VNS can be modulated by or be the reflection of EEG changes.

Comparison of MRI, EEG, EPs and ECD-SPECT in Wilson's disease

OBJECTIVES

The purpose of this study is to evaluate the efficiency of a few methodologies in detecting anatomo-functional brain abnormalities in patients with Wilson's disease.

MATERIALS AND METHODS

Twenty-three patients with Wilson's disease underwent almost simultaneously brain magnetic resonance imaging (MRI), computerized electroencephalography (EEG), multimodal evoked potentials (EPs) and ECD single photon computerized tomography (SPECT) evaluation. The clinical picture was of the neurologic type in 8 patients and of the hepatic type in 15.

RESULTS

MRI was abnormal in 7 patients with neurological manifestations. The EPs proved pathologic in 7 neurologically symptomatic patients and in 4 cases with hepatic form. These results agree with those reported in other case studies. The EEG records were abnormal only in 3 cases. Nevertheless, the most interesting finding of this study is the particular frequency (86%) of diffuse or focal decrease of ECD uptake shown by brain SPECT.

CONCLUSION

We highlight the use of this interesting procedure in the therapeutic monitoring of this disease.

Correlation between cerebral perfusion and hyperventilation enhanced focal spiking activity

Single photon emission computed tomography (SPECT) has frequently been used to investigate cerebral brain perfusion (CBP) occurring ictally and inter-ictally in epileptic patients. Several studies have addressed the multimodal analysis of the modifications occurring in cerebral areas involved in seizure activity, by correlating SPECT with electroencephalografic (EEG) recordings during ictal and inter-ictal epileptiform lateralized discharges (IELDs). Although these studies have yielded interesting results, variations in regional CBP (rCBP) observed during ictal events are difficult to interpret since the areas of altered rCBP might reflect not only events restricted to the epileptogenic focus, but also large fluctuations determined by seizure spread. Inter-ictal rCBP correlates with the area generating the local EEG epileptogenic activity in a limited percentage of studies. Hyperventilation (HPV) represents a well established EEG activation procedure aimed at enhancing epileptiform discharges. Since HPV-enhanced IELDs may help analyze the CBP pathophysiology in inter-ictal epilepsy, in the present study we investigate this specific aspect co-registering EEG with SPECT in subjects affected by partial epilepsy responding to HPV with IELD enhancement without seizure precipitation. This study suggests a correlation between localized increase in rCBP and HPV-induced IELDs and provides a tool to discuss uncommon aspects of the physiology of rCBP during the inter-ictal state in the epileptogenic areas.

Conjugal amyotrophic lateral sclerosis: a report on a couple from Sardinia, Italy

A conjugal case of amyotrophic lateral sclerosis (ALS) observed in Sardinia, Italy is reported. This is believed to be the ninth such observation described in the literature. The couple had lived together for 38 years in a house adjacent to the distillery they owned. No exogenous factors were revealed which could explain the genesis of the disease in either patients. Particularly, exposure to alcohol does not appear to have been involved in causing ALS. On the basis of statistical and epidemiological evaluations, the most likely explanation is that this association was purely coincidental.

Hippocampal theta activity after systemic administration of a non-peptide delta-opioid agonist in freely-moving rats: relationship to D1 dopamine receptors

Hippocampal theta activity was acquired and processed off-line from digitized EEG recordings after subcutaneous (s.c.) administration of the non-opioid delta agonist BW 373U86 (0.5-2.5 mg/kg) in freely-moving rats. Relative theta power spectral analysis, implemented by a signal processing software, showed that BW 373U86 induced a dose-dependent increase in the slow component of theta band (Type 2 theta), while movement-related fast theta band (Type 1 theta) failed to show significant changes. Moreover, the increase in relative Type 2 theta power showed a maximal change at 1 mg/kg of BW 373U86, while higher doses, although effective in increasing relative Type 2 theta, induced locomotion and irregularly increased Type 1 hippocampal theta activity. The administration of 10.0 mg/kg of the delta antagonist Naltrindole (NLI) 30 min before BW 373U86, abolished hippocampal Type 2 theta increase. The rise of relative Type 2 theta power induced by BW 373U86 (1-2.5 mg/kg) was greatly attenuated by 0.1 mg/kg of the selective dopamine (DA) D1 antagonist SCH 23390. Administration of 0.1 mg/kg of SCH 23390 alone did not modify hippocampal Type 2 theta. These results indicate that delta receptors modulate the expression of hippocampal Type 2 theta and dopamine, through D1 receptors, exerts a permissive role on this influence.

5-HT1A agonists induce hippocampal theta activity in freely moving cats: role of presynaptic 5-HT1A receptors

Electrical activity in the dorsal hippocampus was recorded in freely moving cats in response to intravenous administration of 5-HT1A agonist and antagonist drugs. Administration of low doses of the selective 5-HT1A agonists 8-OH-DPAT (5-20 micrograms/kg) and ipsapirone (20-100 micrograms/kg) produced rhythmic slow activity (theta) in the hippocampal EEG within 30 s. Similar effects were observed with BMY 7378 (20 and 100 micrograms/kg), which acts as an agonist at presynaptic (somatodendritic) 5-HT1A receptors and as an antagonist at postsynaptic 5-HT1A receptors. Power spectral analyses showed that all three compounds produced a dose-dependent increase in the EEG power occurring in the theta frequency band (3.5-8.0 Hz) as a proportion of total power from 0.25 to 30.0 Hz (relative theta power). The increase in relative theta power produced by 8-OH-DPAT (20 micrograms/kg) was greatly attenuated by spiperone (1 mg/kg), a highly effective 5-HT1A autoreceptor antagonist. Administration of spiperone alone had no significant effect on relative theta power. These results are discussed in relationship to the effects of these drugs on serotonergic neuronal activity. Our results suggest that preferential activation of presynaptic 5-HT1A receptors, and subsequent inhibition of serotonin neurotransmission, facilitates the appearance of hippocampal theta activity in awake cats.

C-Fos expression as a molecular marker in corticotropin-releasing factor-induced seizures

Expression of Fos-like protein has been shown to increase after seizures in several types of experimentally induced epilepsies. The intracerebroventricular (icv) injection of murine corticotropin-releasing factor (CRF) in rats (10 micrograms), shows an electroencephalographic (EEG) spiking activity restricted to the amygdaloid-hippocampal area. This EEG seizure pattern represents a unique model of localized epileptic activity induced by a neuropeptide. C-fos expression after icv CRF has been considered a useful tool in mapping areas involved in stress and in seizure activity. Our results show that 1 microgram and 10 micrograms CRF are able to induce c-fos activation in several brain areas. Moreover, the present study not only details c-fos expression increase in brain areas directly involved in spiking activation, such as the amygdaloid-hippocampal region, but also maps the possible contribution of other regions to seizure manifestations.

A subgroup of dorsal raphe serotonergic neurons in the cat is strongly activated during oral-buccal movements

A subgroup of approximately 25% of dorsal raphe nucleus serotonergic neurons in cat was strongly activated in association with oral-buccal movements, such as chewing, licking, and grooming. The mean magnitude of increase in neuronal activity for these cells was approximately 100% above the spontaneous waking level. However, some of these cells were activated by as much as 200-300%. The neuronal activation frequently preceded the initiation of the movement and stopped abruptly in association with either pauses in the motor sequence or with its cessation. Most of the neurons in this subgroup were also strongly and preferentially activated by somatosensory stimuli applied to the head, neck, and face. During orientation to a strong or novel stimulus, the activity of these neurons fell silent for periods of 1-5 s. These data and results from our previous studies of medullary raphe neurons are discussed within the context of the general role of serotonin in tonic and central pattern generator-related motor activity.

Failure of naloxone to modify electroencephalogram interictal epileptiform discharges in patients with primary generalized epilepsy after slation

Sleep deprivation (SD) is a method widely used to activate EEG epilept oform activity, but the basis of this effect remains unknown. One possibilty is that SD shares a common mechanism with physical and psychological stresses that also precipitate seizures. Because endogenous opioids are released during stress, opioids may play a role in enhancing epileptiform EEG patterns after SD. We report the effects of SD on EEG epileptiform activity in a small but highly homogeneous population of 13 epileptic patients with idiopathic (primary) generalized epilepsy (IGE). SD increased EEG interictal epileptiform discharges (IEDs); this activation was not modified by naloxone (NAL). Our results, in contrast to those of previous investigations of localization-related epilepsy, which showed an increase in IEDs after NAL administration, suggest a possible difference in the mechanism whereby SD enhances IEDs in IGE and localization-related epilepsy.

Microdialysis measurement of cortical and hippocampal acetylcholine release during sleep-wake cycle in freely moving cats

The variations of Acetylcholine (ACh) release in the cerebral cortex and dorsal hippocampus were monitored by microdialysis during the electroencephalographically recorded sleep-waking cycle in freely moving cats. The results show a state-dependent variation in ACh output in both the cortex and the hippocampus. ACh release increased by approximately 100% during quiet waking (QW) and by 175% during active waking (AW) as referred to slow wave sleep (SWS) baseline. In contrast, a clear difference between the two areas was observed during REM sleep. During this stage ACh release in the cortex reached approximately the same values observed during QW, while in the hippocampus ACh release rose to about 4-fold the level obtained during SWS or twice that of QW. The results support the idea that the increase in ACh release in the cortex reflects the desynchronized EEG of wakefulness and REM sleep, while the marked increase of ACh during REM in the hippocampus may be related to the sustained theta activity in this area.

Single-unit responses of serotonergic dorsal raphe neurons to 5-HT1A agonist and antagonist drug administration in behaving cats

Single-unit activity of serotonergic neurons in the dorsal raphe nucleus was recorded in free-moving cats in response to i.v. administration of 5-hydroxytryptamine (5-HT)1A agonist and antagonist drugs. The 5-HT1A agonist drugs 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), ipsapirone, buspirone and 5-methoxy-N,N-dimethyltryptamine produced a rapid, dose-dependent inhibition of neuronal activity. 8-OH-DPAT (ED50 = 1.5 micrograms/kg) was approximately 45 times more potent than ipsapirone, buspirone or 5-methoxy-N,N-dimethyltryptamine (ED50 range = 6.0-6.8 micrograms/kg) in producing inhibition, and all drugs were more effective when cats were inactive (e.g., drowsiness) than during periods of behavioral arousal (e.g., active waking). Administration of the 5-HT1A autoreceptor antagonist spiperone (0.25 and 1 mg/kg) produced a rapid, dose-dependent increase in the firing rate, suggesting that under physiological conditions serotonergic neurons are controlled by tonic feedback inhibition. This effect was evident during wakefulness (a period of relatively high neuronal activity), but not during sleep (a period of relatively low neuronal activity). Spiperone also blocked the inhibitory action of 8-OH-DPAT in a dose- and time-dependent manner. There was a strong positive correlation between the magnitude of spiperone-induced neuronal activation and blockade of 8-OH-DPAT-induced neuronal suppression. These effects of spiperone cannot be attributed to its dopaminergic D2 or serotonergic 5-HT2 antagonist properties, because administration of haloperidol and ritanserin produced no increase in neuronal activity and did not block the action of 8-OH-DPAT. These results confirm the marked sensitivity of serotonergic dorsal raphe nucleus neurons to selective 5-HT1A agonist compounds in unanesthetized animals and suggest that 5-HT1A somatodendritic autoreceptors exert a tonic inhibitory influence on the firing rate of these neurons during periods of behavioral activation, but not during periods of behavioral quiescence.

Effects of the putative 5-hydroxytryptamine1A antagonists BMY 7378, NAN 190 and (-)-propranolol on serotonergic dorsal raphe unit activity in behaving cats

Recent evidence from our laboratory has demonstrated that blockade of somatodendritic 5-hydroxytryptamine (5-HT)1A autoreceptors by systemic administration of spiperone increases the firing rate of central serotonergic neurons in awake cats. The present study examines the effects of three other putative 5-HT1A antagonists (BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro [4,5]decane-7,9-dione), NAN 190 [1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine) and (-)-propranolol) on the single-unit activity of serotonergic neurons recorded in the dorsal raphe nucleus of free-moving cats. Systemic administration of the phenylpiperazine derivatives BMY 7378 (5-100 micrograms/kg i.v.) and NAN 190 (5-250 micrograms/kg i.v.) produced a rapid, dose-dependent inhibition of neuronal activity with BMY 7378 being approximately twice as potent as NAN 190 (ED50 = 15.3 micrograms/kg vs. 34.2 micrograms/kg). The suppression of neuronal activity produced by both compounds was greatly attenuated by spiperone (1 mg/kg i.v.). Systemic administration of (-)-propranolol (2 and 4 mg/kg i.v.) produced a modest suppression of serotonergic neuronal activity which did not appear to be dose-related. The ability of BMY 7378, NAN 190 and (-)-propranolol to block the suppression of neuronal activity produced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective 5-HT1A agonist, was also examined. Pretreatment with these compounds had no significant effect on the inhibitory response of serotonergic neurons to 8-OH-DPAT challenge. These results indicate that BMY 7378 and NAN 190 act as agonists rather than antagonists at the somatodendritic 5-HT1A autoreceptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Chordoma of the cervical spine. Case report

We present a case of chordoma of cervical spine with spinal cord compression at the level C4-C5-C6 in a woman of 65 years old. The diagnosis depends on the results of the histological studies and especially the studies of the labeled elements as protein S 100. For the operation was used an anterior approach and a somatectomy of the interested vertebrae. The cervical spine was synthesized using a bone autograft and the stabilization was made possible through a HaloVest. The patient then underwent radiotherapy (50 Gy); the preoperative deficit disappeared totally and at the present moment there are no signs of clinical on radiological relapse.

Epilepsy in congenital lipodystrophy. Case report

A case of congenital lipodystrophy complicated by complex-partial epilepsy is reported in a nine-year-old girl. The peculiarity of this rare case is represented by partial complex epilepsy with diffuse electroencephalographic alterations represented by a continuous seizure-like pattern that persisted unmodified despite the successful antiepileptic treatment. Although the etiopathology of lipodystrophy is, at present, still elusive, we hypothesize that the primitive dysfunction of lipidic metabolism plays a critical role in both determining central nervous system (CNS) alterations and the findings that characterized this extremely rare disease.

Altered EEG pattern in aromatic hydrocarbon intoxication. A case report

A case of acute intoxication after both cutaneous and inhalatory absorption of a mixture of organic solvents (toluene and benzene) is reported. The peculiarity of this case is represented by the abnormal EEG findings: paroxysmal slow waves at the beginning of the intoxication, persisting, although attenuated, days after the patient's complete recovery. Moreover, the fact that other investigations were normal gives further support to the significance of routine EEG recording in monitoring the involvement of CNS in cases of acute exposure to aromatic organic solvents.

Clonidine prevents corticotropin releasing factor-induced epileptogenic activity in rats

Studies have shown that intracerebroventricular (i.c.v.) injection (10-20 micrograms) of corticotropin releasing factor (CRF) in rats induces epileptiform activity characterized by a regular (pacemaker-like) spiking pattern located in hippocampal leads. CRF has also been shown to increase the firing rate of noradrenergic neurons in the locus ceruleus. Our experiments clarified the possible role of norepinephrine (NE) in mediating hippocampal activity of CRF. Intraperitoneal (i.p.) injection of the alpha 2-agonist clonidine at a dose of 0.5-5 micrograms/kg prevented, in a dose-related manner, the hippocampal epileptiform activity induced by CRF (20 micrograms i.c.v.). Our results suggest a possible role of NE in CRF-induced spiking activity.

Neonatal monosodium glutamate abolishes corticotropin-releasing factor-induced epileptogenic activity in rats

Intracerebroventricular (i.c.v.) injection of rat corticotropin-releasing factor (rCRF) at doses of 5-20 micrograms in rats induces epileptogenic activity characterized by pacemaker-like spikes localized in the hippocampal leads. Such an effect was still present in rats neonatally treated with saline but was absent in those neonatally treated with monosodium glutamate (MSG), a treatment that caused marked changes in the concentration of several brain neurotransmitters and neuropeptides in hypothalamic nuclei where CRF is highly concentrated and is believed to induce endocrinologic and behavioral effects. The present results suggest the rCRF-induced spiking activity is mediated by activation of neuronal pathways sensitive to MSG neurotoxic effect.

Failure of acute diphenylhydantoin to affect the spontaneous electrical activity of dopamine cells

Diphenylhydantoin (DPH) has recently been reported to produce dopaminergic (DA) supersensitivity in animals. These results have suggested that the dyskinesias observed in humans after DPH, although rare, might be regarded as a neuroleptic-like effect. Indeed dyskinesias would be induced by an inactivation of post-synaptic DAergic receptors, operated by DPH, and therefore reminiscent of that observable in neuroleptic treatment. In order to investigate this matter, we studied the effects of i.v. DPH on the extracellular single unit activity of DAergic cells located in mid-brain areas of rats. DPH was injected alone or in combination with DA antagonists such as L-sulpiride (L-SULP) and haloperidol (HAL), or the DAergic agonist apomorphine (APO). Our results show that DPH did not affect spontaneous DAergic firing rate and also failed to modify the known action of the DA agonists and antagonists which were tested on these neurons.

Allopurinol add-on treatment in intractable seizures

Recent reports in clinical literature have suggested an antiepileptic effect of the xanthine oxidase inhibitor Allopurinol (ALL) when added to traditional drugs. However, other reports have failed to confirm beneficial effects of this drug. In view of these conflicting results, we have carried out a study aimed at evaluate the effects of ALL in different forms of epilepsy. The result that ALL possesses some antiepileptic effects in Lennox-Gastaut syndromes, characterized by numerous and severe fits, while it is scarcely effective in other forms of epilepsy, suggests that ALL might be involved in the purinergic-mediated inhibition similar to that described in experimental "status epilepticus" studies in animal models.

Corticotropin-releasing factor (CRF) increases paradoxical sleep (PS) rebound in PS-deprived rats

The intracerebroventricular injection (1 microgram) of murine corticotropin-releasing factor (r-CRF) to rats after 72 h of sleep deprivation markedly postponed the sleep onset, reduced slow wave sleep and prolonged the duration of paradoxical sleep (PS) episodes. Moreover, CRF is-to our knowledge-the first compound to be able to further prolong PS in a condition (sleep deprivation) in which its duration is already increased. Our findings raise the possibility that CRF might play a physiological role in the regulation of the sleep-wakefulness cycle.

Epidemiological study of myasthenia gravis in Sardinia, Italy (1958-1986)

From 1.1.1958 to 31.12.1986, 110 cases of MG were observed in Sardinia, with a mean annual incidence of 2.5 x 1,000,000 inhabitants and prevalence rates of 7.5, 17.6, 31.4 and 45.0 x 1,000,000 inhabitants respectively (prevalence days: 15.10.1961, 24.10.1971, 25.10.1981 and 31.12.1986). The disease was found to be more frequent in women. There were no differences in the distribution of MG in various areas of the island. The muscle group more frequently involved at onset was the ocular. In 6.4% of patients an association with thyroid disorders was observed. The mortality of MG patients was significantly higher than expected. Removal of the thymus, carried out in 58 patients, was shown to be useful in the treatment of the disease, particularly in patients without thymomas. No familial cases were observed.

Antagonism of ethanol effects by Ro 15-4513: an electrophysiological analysis

Ethanol (ETH) and general anesthetics have been reported to facilitate the chloride channel opening, possibly, or at least partly, through an interaction with the GABA-benzodiazepine (BZ) receptor-gated chloride ionophore "supramolecular complex". Recently Ro 15-4513, a novel BZ ligand, has been indicated as a potent and selective antagonist of various ETH-induced behavioral and biochemical effects. However, since its precise characterization is still a matter of debate, we have tested and compared the effect of Ro 15-4513, as well as its antagonism against ETH, in two objective electrophysiological parameters, i.e., the electroencephalograph (EEG) pattern in freely moving rats and single unit activity of reticulata neurons. Ro 15-4513 produced an EEG state of alertness and antagonized the behavioral impairment and the EEG deterioration by ETH. However, while its protective action was consistent against moderate doses (2 g/kg) of ETH, it was much less evident versus higher doses (4 and 8 g/kg). On reticulata cells, Ro 15-4513 potently stimulated their spontaneous firing and reversed the depression by both ETH and Na-pentobarbital. Moreover, the beta-carboline DMCM also had similar effects. The "pure" BZ antagonist Ro 15-1788 was completely inefective against ETH, yet fully cancelled the reversing actions of Ro 15-4513 and DMCM upon ETH or Na-pentobarbital effects. It is concluded that Ro 15-4513 behaves as a BZ inverse agonist, so that its opposition to ETH and Na-pentobarbital is probably the result of its "negative" coupling with the BZ recognition site that triggers the closing of chloride channels. It suggests that BZ inverse agonists might constitute, in the near future, a new class of analeptic drugs.

Localized epileptiform activity induced by murine CRF in rats

Murine corticotropin releasing factor (rCRF), injected intracerebroventricularly into rats at a dose of 10 micrograms produced increased motor activity, grooming, and recurrent episodes of epileptic activity localized in the hippocampal leads. Such activity persisted for approximately 5 h and was characterized by recurrent trains of biphasic spikes never associated with behavioral signs of epilepsy. The intraperitoneal administration of carbamazepine (15 and 30 mg/kg) reduced the epileptic activity for approximately 90 and 120 min, respectively, whereas that of naloxone (8 mg/kg) was ineffective. The results suggest that rCRF-induced spiking activity might be a model of temporal lobe epilepsy.

The benzodiazepine recognition site inverse agonists Ro 15-4513 and FG 7142 both antagonize the EEG effects of ethanol in the rat

The aim of the present study was to compare the ability of Ro 15-4513 and FG 7142, two inverse agonists for benzodiazepine recognition sites, to antagonize the EEG effects of ethanol in freely moving rats. Ethanol (2.5 g/kg, p.o.) induced sedation and ataxia associated with a progressive suppression of the fast cortical activities and an enhancement of low frequencies in both cortical and hippocampal tracings. In contrast, Ro 15-4513 (2 mg/kg, i.p.) and FG 7142 (10 mg/kg, i.p.) both caused a state of alertness associated with desynchronized cortical activity and theta hippocampal rhythm as well as spiking activity which was predominantly observed in the cortical tracings. When rats were treated with FG 7142 or RO 15-4513 either before or after ethanol, a reciprocal antagonism of the behavioral and EEG effects of ethanol and of the partial inverse agonists was observed. These data support the view that the anti-ethanol effects of Ro 15-4513 may be related to its partial inverse agonist properties.

Paradoxical reactions elicited by diazepam in children with classic autism

Administration of diazepam (10 mg i.m.) to seven children (two girls and five boys) affected by infantile autism elicited paradoxical behavioural responses. Mainly, anxiogenic effect, unsocialized aggressive behaviour and explosive aggression were dramatically increased in comparison with the same symptoms present before and after treatment. The results show for the first time that benzodiazepines may elicit paradoxical behavioural response in autistic children. The possible involvement of an altered function at the level of GABA/benzodiazepine receptor complex is discussed.

Different epileptogenic activities of murine and ovine corticotropin-releasing factor

The behavioral and EEG effects of rat and ovine corticotropin releasing factor (r- and o-CRF) were compared. Both peptides were injected intracerebroventricularly into rats through chronically implanted cannulae. At the doses of 0.1 and 1 microgram both peptides activated the EEG and stimulated motor activity. At the dose of 10 micrograms they produced spiking activity. However, while o-CRF-induced spiking activity was present both in the hippocampus and in the cortical leads and was associated with generalized myoclonic movements, that induced by r-CRF was confined in the hippocampus and was not accompanied by myoclonic movements. Spiking activity induced by r-CRF was suppressed by verapamil, but was not influenced by naloxone.

Aminophylline antagonizes diazepam-induced anesthesia and EEG changes in humans

General anesthesia was induced in eight subjects by the slow IV injection of 60 mg diazepam. During the anesthetic effect, the EEG was characterized by 3-5 Hz high voltage activity. Immediate recovery of consciousness and reversal of the EEG pattern to fast low voltage activity was obtained after the IV injection of 60 mg aminophylline. On the other hand, three diazepam-treated subjects who received IV saline instead of aminophylline recovered from anesthesia 73-120 min after saline.

Increased paroxysmal activity of partial seizures in man by apomorphine

In order to study the role of dopamine (DA) in the regulation of seizure mechanisms in man, a non-emetic dose of apomorphine, a direct stimulant of DA receptors, was administered to eight patients effected by different types of epilepsy. The EEG changes induced by apomorphine administration in comparison to those elicited by promazine or placebo were evaluated in a double blind cross-over study. Similarly to promazine treatment, apomorphine worsened the EEG recordings of some patients. The apomorphine-induced increase in paroxysmal activity was observed in patients affected by partial epilepsy and was not related to the sleep-inducing properties of the drug. This effect is interpreted as being the result of a stimulation of DA autoreceptors, mediating a decrease of dopaminergic activity in the central nervous system. The use of apomorphine as an EEG activating agent is suggested.

Treatment of Sydenham's chorea with a combination of L-dopa and a peripheral dopa decarboxylase inhibitor

Two male patients suffering from Sydenham's chorea were treated with a combination of L-Dopa and a peripheral decarboxylase inhibitor. This treatment markedly reduced in one patient and totally suppressed in the other the abnormal involuntary movements present in this disease.