Signs Of Convulsions Research Articles

Evaluation of the anticonvulsant activity of ethanol leaf extract of Panicum maximum in pentylenetetrazole and strychnine induced seizure in mice.

Epilepsy is a chronic neurological condition affecting around 50 million people worldwide. This study evaluated the anticonvulsant effect of Panicium maxmium in pentylenetetrazole (PTZ) and strychnine (STN) induced convulsions in mice. For each model, 25 mice were divided into five groups; group 1 received 10 ml/kg distilled water, groups 2-4 received 100 mg/kg, 200 mg/kg and 400 mg/kg of extract p.o respectively. Group 5 received 3 mg/kg of diazepam p.o. Convulsion was induced intraperitoneally using PTZ and STN, thirty minutes after the extract was administered. The onset of myoclonic, tonic-clonic seizure, time of death within 60 minutes of PTZ and STN administration were monitored. Data were statistically analyzed using one-way ANOVA followed by Dunnet’s comparison tests. In STN-induced seizure model, 100 mg/kg of P. maximum exhibited a significant (p < 0.001) anticonvulsant activity by delaying myoclonic seizure onset in mice when compared to the control. Significant (p < 0.001) activity was also observed in the onset of tonic clonic seizure at same dose when compared to control. In PTZ-induced seizure model, 200 mg/kg exhibited more significant (p < 0.001) activity followed by 100 mg/kg (p < 0.05) by delaying myoclonic seizure onset in mice when compared to the control. Significant (p < 0.001) activity were observed in tonic clonic phase at same doses respectively. The different doses administered couldn’t protect the mice from death. Diazepam, standard drug used, protected all the animals without any signs of convulsions. The results provide evidence that the extract possesses anticonvulsant activity.

Anticonvulsant and antioxidant activities of crude flavonoid extract of Matricaria chamomilla L. against convulsions induced by pentylenetetrazole in chicks

In the current study, crude flavonoid extract ofMatricaria chamomilla L. (MC) was used to evaluate anticonvulsant, and antioxidant activities on pentylenetetrazole (PTZ) induced convulsion in chicks. The biochemical estimation was done by measuring brain tissue neurotransmitters (gamma-aminobutyric acid GABA and glutamate), oxidative stress biomarkers in serum (catalase CAT, glutathione reductase GR, malondialdehyde MDA, and 8-isoprostane), serum electrolytes (potassium Ka+, sodium Na+, chloride Cl-, ionized calcium iCa2+, total calcium TCa2+), pH of serum, and glucose level in serum. Seventy-two broiler chicks (2 weeks old) were randomly divided into six groups (n=12): The first group (negative control) received the normal saline subcutaneous injection, the second group (positive control) received PTZ 90 mg/kg subcutaneous injection, and the third group treated with sodium valproate (SV) 200mg/kg orally. The fourth, fifth and sixth groups treated with 20, 40, 80 mg/kg of crude flavonoid extract of MC respectively orally for six days before PTZ injection. Thirty minutes post-treatment of the last dose, the chicks in the (third to sixth) groups received PTZ. The results showed that the crude flavonoid extract of MC attenuated the convulsion signs and mortality dose-dependently. The pretreated crude flavonoid extract at the dose of 80mg/kg showed a significant increase in the serum level of Na+ and iCa2+, and a decrease in 8-isoprostane. In conclusion: the crude flavonoid extract of MC 80mg/kg possesses mild to moderate anticonvulsant and antioxidant effects.

The effects of crude alkaloid extract of Matricaria chamomilla L. on convulsions induced by pentylenetetrazole in chicks

The present research was designed to evaluate the protective effect of crude alkaloid extract of Matricaria chamomilla L. (MC) against pentylenetetrazole (PTZ) induced convulsions in chicks. A total of seventy-two chicks were randomly divided into six groups each one consisting of 12 chicks. The first group was considered to be a negative group that received subcutaneous injection of normal saline, the second group (positive control) received subcutaneous injection of PTZ (90 mg/kg), and the third group received sodium valproate (200 mg/kg) orally for six days. The other groups (fourth, fifth and sixth) were treated with single intraperitoneal injection of crude alkaloids extract of MC (20, 40, 80 mg/kg) respectively. After 30 minutes of the treatment, the groups (third to sixth) received PTZ and observed the convulsion signs for the next 30 minutes. At the end of the experiment, various biochemical parameters were assessed including, brain gamma-aminobutyric acid (GABA) and glutamate, serum catalase (CAT), glutathione reductase (GR), malondialdehyde (MDA), and 8-isoprostane, and some electrolytes (potassium K+, sodium Na+, chloride Cl-, ionized calcium iCa2+, total calcium TCa2+), pH, and glucose levels in serum. The results indicated that the group treated with crude alkaloids extract at higher dose (80 mg/kg) showed a significant increase in CAT and significantly decreased in 8-isoprostane, and an increase in Na+ ions concentration in serum. It was concluded that pretreatment of crude alkaloids extract (80 mg/kg) of MC offers anticonvulsant activity by reducing the mortality rate induced by PTZ, as well as it plays an important role in inhibiting oxidative stress.

Strongyloides papillosus causes sudden death in weaned calves on New York dairies.

Outbreaks of sudden death in apparently healthy weaned dairy calves due to Strongyloides papillosus parasitism were diagnosed on 2 separate and independent New York (NY) dairies. Most calves were found dead; however, 1 calf observed while dying showed signs of tachycardia, tachypnea, vocalization, and convulsions shortly before death. In 6 affected heifers that underwent post-mortem examination, precocious bilaterally symmetric mammary gland enlargement was seen. A portion of their parasitized living cohorts also demonstrated similar mammary gland enlargement. A diagnosis of S papillosus hyperinfection was made based upon the presence of high numbers of S papillosus ova in feces, and confirmation by S papillosus-specific PCR assays. Consistent histopathological findings in affected calves included generalized mammary gland vascular congestion, interstitial edema and hemorrhage with ductal hyperplasia. Mild multifocal cardiomyocyte degeneration was found in 5 of 14 calves examined. Factors believed to contribute to the parasite's environmental amplification and host hyperinfection included group housing on wood shavings and high environmental temperatures and humidity. Treatment of calves with doramectin pour-on stopped mortality and resolved the udder enlargement. Similar outbreaks have previously been described in Japan and South Bohemia (Czech Republic), where researchers hypothesized that sudden death may be due to fatal arrhythmia caused by a parasite-associated cardiotoxin. This report highlights the importance of including S papillosus among the differential diagnoses for sudden death alone or together with precocious udder enlargement in calves kept in confinement housing.

About the essence of stuttering. Paikin (Sovetsk, psychoneur., No. 6, 1932)

Paikin. On the essence of stuttering (Sovetsk, psychonevr., No. 6, 1932). The author approaches the problem of stuttering from a genetic point of view. He sees the root of stuttering in the initial clonus, that is, in the repetition of words and syllables without signs of convulsion, which is observed in children during the period of speech development, as a physiological phenomenon. On the basis of the repetition of words and syllables of non-convulsive phenomena, the author denotes "clonus" completely incomprehensible. "With unusual excessive emotional stimuli, early speech mechanisms are revived, the clonic repetition of syllables and words that are normally inhibited", and this leads to stuttering.

Amomum tsaoko fruit extract exerts anticonvulsant effects through suppression of oxidative stress and neuroinflammation in a pentylenetetrazol kindling model of epilepsy in mice.

BackgroundChronic epilepsy is a multifaceted common brain disorder with manifold underlying factors. Epilepsy affects around 70 million peoples worldwide. Amomum tsaoko is a perennial herbaceous plant that is extensively cultivated in many provinces of China reported to exert immense biological activities.ObjectiveThis research work was aimed to reveal the therapeutic actions of ethanolic extract of A.tsaoko fruits (EE-ATF) against the pentylenetetrazol (PTZ)-provoked convulsive seizures in the mice.MethodologyThe convulsive seizures were provoked to the animals via administering 70 mg/kg of PTZ through intraperitoneally to trigger the convulsive seizures then treated with the EE-ATF at 50, 75, and 100 mg/kg orally 30 min prior to PTZ challenge. After the 30 min of PTZ challenge, animals closely monitored for signs of convulsion, generalized clonic and tonic convulsion durations, and mortality. A sub-convulsive dose 35 mg/kg of PTZ was used to provoke the kindling and seizure stages were examined using standard method. The levels of dopamine, GABA, glutamate, and Na + K + ATPase and Ca + ATPase activities in the brain tissues were studied using marker specific assay kits. The oxidative stress and antioxidant markers studied using standard methods. The mRNA expressions of COX-2, TNF-α, NF-κB, TLR-4, and IL-1β in the brain tissues were studied using RT-PCR analysis. The brain tissues were examined histologically.ResultsEE-ATF treatment remarkably decreased the onset and duration of convulsion and suppressed the seizure severity and mortality in the PTZ animals. EE-ATF treatment appreciably ameliorated the PTZ triggered modifications in the GABA, glutamate, dopamine levels and Ca + 2ATPase and Na + K + ATPase activities in the brain tissues. EE-ATF suppressed the mRNA expressions of NF-κB, IL-1β, TLR-4, TNF-α, and COX-2. The status of antioxidants were elevated by the EE-ATF. Histological findings also demonstrated the curative actions of EE-ATF.ConclusionOur findings evidenced that the EE-ATF substantially ameliorated the PTZ-provoked convulsive seizures in the mice.

Management of childhood pneumonia in Nigeria.

Management of childhood pneumonia in Nigeria.

Comparative evaluation of different treatment schemes for aseptic meningoencephalitis in dogs of dwarf breeds

The article presents the results of treatment of aseptic meningoencephalitis in dogs of dwarf breeds. Diagnostics included a thorough neurological examination: assessment of mental status, ability to perform diagnostic tests, proprioceptive and postural reaction, the consistency and symmetry of cranial reflexes, including of pupil response to light and response to the threat, the presence of involuntary movements and forced poses, the intensity of the muscle tone and tendon reflexes. If an animal is suspected of having a brain lesion, other possible causes of encephalopathy were excluded. For this purpose, a General blood test was performed (to detect signs of inflammation, anemia); a detailed biochemical blood test (excluding renal and hepatic encephalopathy, indirect signs of the presence of a portosystemic shunt); if a portosystemic shunt was suspected, a blood test for bile acids was performed; when excluding all other causes of damage to the central nervous system. Magnetic resonance imaging of the brain was performed with contrast with the use of the drug OmniScan. During the magnetic resonance imaging, multiple foci were detected in all parts of the brain, including in the thalamus and trunk; including in some animals, foci that have a tendency to decay and form a necrotic cavity. It was established that before the start of treatment, animals had a wobbly gait, convulsive signs, a comatose state in some dogs, and weak visual reflexes. As a result of studies of morphological and biochemical parameters of blood in dogs, it was found that all the data obtained were within the reference values and did not have significant significance in the diagnosis of aseptic meningoencephalitis. Against the background of etiotropic and symptomatic therapy, positive dynamics was observed in patients with aseptic meningoencephalitis.

An Expert System for the Prognostication of the Brain and Nerve Diseases in Children with Convulsion Signs Based on Certainty Factors (Preprint)

An Expert System for the Prognostication of the Brain and Nerve Diseases in Children with Convulsion Signs Based on Certainty Factors (Preprint)

Changes in Brain Electrical Activity on Formation of Status Epilepticus in a Lithium-Pilocarpine Model in Rats with Different Levels of Convulsive Readiness

Chronic experiments on Krushinskii–Molodkina rats, which have an inborn predisposition to audiogenic convulsions, and Wistar rats, which are resistant to the convulsive actions of sound, recorded electrograms from the somatosensory, auditory, and visual areas of the cortex, the caudate nucleus, the hippocampus, and the mediodorsal nucleus of the thalamus during formation of generalized convulsive status epilepticus (SE) in a lithium-pilocarpine model of epilepsy. SE was found to occur in Krushinskii–Molodkina rats after i.m. administration of pilocarpine at a minimal dose of 15 mg/kg and in Wistar rats after a dose of 25 mg/kg. Six EEG patterns characteristic of sequentially substituting phases in the development of SE are described, from its initiation to its completion. Behavioral signs of convulsions were identified for each phase in the development of SE. The sequence and main EEG characteristics in rats of both strains coincided, as did their behavioral convulsive manifestations, with the exception of the latent period of onset of phase 1: in Krushinskii–Molodkina rats, this was significantly longer than in Wistar rats (12.8 ± 1.1 versus 22.5 ± 0.7 min). Rats with an innate predisposition to audiogenic convulsions thus had greater sensitivity to the effects of pilocarpine.

Brevetoxin exposure in sea turtles in south Texas (USA) during Karenia brevis red tide.

Five green (Chelonia mydas) and 11 Kemp's ridley (Lepidochelys kempii) sea turtles found dead, or that died soon after stranding, on the southern Texas (USA) coast during 2 Karenia brevis blooms (October 2015, September-October 2016) were tested for exposure to brevetoxins (PbTx). Tissues (liver, kidney) and digesta (stomach and intestinal contents) were analyzed by ELISA. Three green turtles found alive during the 2015 event and 2 Kemp's ridley turtles found alive during the 2016 event exhibited signs of PbTx exposure, including lethargy and/or convulsions of the head and neck. PbTx were detected in 1 or more tissues or digesta in all 16 stranded turtles. Detected PbTx concentrations ranged from 2 to >2000 ng g-1. Necropsy examination and results of PbTx analysis indicated that 10 of the Kemp's ridleys and 2 of the green turtles died from brevetoxicosis via ingestion. This is the first documentation of sea turtle mortality in Texas attributed to brevetoxicosis.

Comparison of semiologies between tilt-induced psychogenic nonsyncopal collapse and psychogenic nonepileptic seizures.

We sought to characterize the clinical features of tilt-induced psychogenic nonsyncopal collapse (PNSC) from a cohort of young patients and to compare the semiologies between PNSC and EEG-confirmed psychogenic nonepileptic seizures (PNES). A PNSC diagnosis was made if a clinical event occurred during tilt-table testing that the patient regarded as fainting, but neither hypotension nor EEG changes were present. A diagnosis of PNSC was made in 17.6% of all patients referred during the 15-month study period. Cohorts with psychogenic nonsyncopal collapse (n=40) and PNES (n=40) did not differ in age (15.5±2.2 versus 14.6±2.7, p=.11) or female gender (80% versus 72.5%, p=.43). Psychogenic nonsyncopal collapse events were briefer than PNES events (median: 45 versus 201.5s, p<.001). Negative motor signs (head drop, body limpness) predominated in PNSC (85% versus 20%, p<.001), while the positive motor signs of convulsion occurred more often with PNES (90% versus 30%, p<.001). Behavioral arrest (25% versus 32.5%, p=.46) and eye closure (85% versus 72.5%, p=.21) did not differ between PNSC and PNES. Patients with PNSC were more likely to be tearful before (30% versus 7.5%, p=.02) and after (62.5% versus 7.5%, p<.001) an event. In conclusion, although overlap exists, the features of PNSC generally appear similar to neurally mediated syncope, while the features of PNES generally appear similar to epileptic seizures. Psychogenic nonsyncopal collapse and PNES likely represent similar disorders that differ primarily by clinical semiologies and referral patterns.

Sleep disruption increases seizure susceptibility: Behavioral and EEG evaluation of an experimental model of sleep apnea

Sleep disruption accompanies sleep apnea as one of its major symptoms. Obstructive sleep apnea is particularly common in patients with refractory epilepsy, but causing factors underlying this are far from being resolved. Therefore, translational studies regarding this issue are important. Our aim was to investigate the effects of sleep disruption on seizure susceptibility of rats using experimental model of lindane-induced refractory seizures.Sleep disruption in male Wistar rats with implanted EEG electrodes was achieved by treadmill method (belt speed set on 0.02m/s for working and 0.00m/s for stop mode, respectively). Animals were assigned to experimental conditions lasting 6h: 1) sleep disruption (sleep interrupted, SI; 30s working and 90s stop mode every 2min; 180cycles in total); 2) activity control (AC, 10min working and 30min stop mode, 9cycles in total); 3) treadmill chamber control (TC, only stop mode). Afterwards, the animals were intraperitoneally treated with lindane (L, 4mg/kg, SI+L, AC+L and TC+L groups) or dimethylsulfoxide (DMSO, SIc, ACc and TCc groups). Convulsive behavior was assessed by seizure incidence, latency time to first seizure, and its severity during 30min after drug administration. Number and duration of ictal periods were determined in recorded EEGs.Incidence and severity of lindane-induced seizures were significantly increased, latency time significantly decreased in animals undergoing sleep disruption (SI+L group) compared with the animals from TC+L. Seizure latency was also significantly decreased in SI+L compared to AC+L groups. Number of ictal periods were increased and duration of it presented tendency to increase in SI+L comparing to AC+L. No convulsive signs were observed in TCc, ACc and SIc groups, as well as no ictal periods in EEG.These results indicate sleep disruption facilitates induction of epileptic activity in rodent model of lindane-epilepsy enabling translational research of this phenomenon.

Effects of dietary lambda-cyhalothrin exposure on bumblebee survival, reproduction, and foraging behavior in laboratory and greenhouse

Bumblebees of Bombus terrestris are indispensible pollinators for ecosystems and for various agricultural crops. Unfortunately, bumblebees are challenged by various stress factors including insecticide applications. Today sublethal effects of various insecticides need to be thoroughly investigated to allow their combined use with pollinators and other beneficial organisms. In this study, we used lambda-cyhalothrin as a model pyrethroid insecticide and investigated lethal and sublethal effects by different dilutions, ranging from 1/10 to 1/100 of its maximum field recommended dosage (MFRC, 37.5 ppm), with the use of a chronic toxicity tests in the laboratory and in flight cages in the greenhouse. In the laboratory, small microcolonies with five bumblebee workers with one being pseudo-queen were used, while in the greenhouse we used queen-right mini-hives where the bumblebees need to fly for pyrethroid-contaminated food. We observed strong sublethal effects in the laboratory with treatments of 1/10 and 1/20 of the MFRC: the nest reproduction was reduced by 49 and 32 %, respectively, and the sugar water consumption by 36 %. With free-flying bumblebees, the toxic effects at 1/10 of the MFRC were more pronounced. A mortality of 88 ± 8 % was observed after only 2 weeks, being twice the mortality in the laboratory microcolonies test (43 ± 11 %). Besides, it should be mentioned that in the greenhouse experiment all queens were dead and most of the workers showed signs of incoordination and convulsion and gradually became apathetic. In conclusion, our results demonstrated the pyrethroid lambda-cyhalothrin with a range of lethal and sublethal effects, both crucial for the development and survival of the B. terrestris colonies. Moreover, this study supports the demand to test insecticide compounds on their safety, especially when the bees have to perform complex tasks such as foraging for their food.

Adverse Events in Healthy Subjects Exposed to Single and Multiple Doses of LY2140023 Monohydrate

Ten phase 1 studies of LY2140023 monohydrate (LY2140023), an mGlu2/3 receptor agonist, in healthy male and female subjects were pooled to evaluate the adverse event profile. These studies included both single-dose (5-200 mg) and multiple-dose (20-160 mg 2 times a day) treatment groups. The percentage of subjects reporting treatment-emergent adverse events (TEAEs) were assessed in placebo and LY2140023 dose groups: 5 to 20, 40, 60 to 80, and more than 80 mg (120-200 mg). The severity and duration of TEAEs were also determined. Electroencephalograms were performed in 1 study to detect if there were any prodromal signs of convulsions or seizures. Subjects who received either placebo or LY2140023 and participated in the single-dose (n = 159) and multiple-dose (n = 102) treatment groups were included in these analyses. No clear trends for increased TEAE incidence occurred with higher doses of LY2140023 in both the single-dose and multiple-dose treatment groups. The TEAEs with the highest incidence were gastrointestinal and nervous system events. No serious adverse events occurred in any of the 10 studies, and most TEAEs were mild in severity and transient in nature. There were no clinically significant changes in electroencephalograms in subjects receiving LY2140023 (n = 26). LY2140023 was generally well tolerated in healthy subjects.

PHYTOCHEMICALS AND ACUTE TOXICITY OF MORINGA OLEIFERA BARKS IN RATS

Objectives: The phytochemicals in Moringa oleifera barks were qualitatively identified in the aqueous and ethanol extracts. The acute oral toxicity of Moringa oleifera aqueous and ethanol extracts were done as per OECD guidelines 423. Methods: The barks were harvested during dry season and air-dried. Extractions using ethanol and water were done. The harvested phytochemicals were qualitatively identified using standard chemicals procedures. Acute toxicity was done on 3 male and 3 female Wistar rats which were administered an initial dose of 300 mg/kg body weight followed by 2000 mg/kg &amp; 5000 mg/kg body weight. The animals were observed for signs of convulsions, tremors, circling, depression, excitement and mortality. Body weight was recorded at 0,7th and 14thday and plasma total protein, blood sugar level, total cholesterol, SGOT &amp; SGPT were measured to evaluate the toxicity of the extracts. Results: The phytochemicals identified were steroids and triterponoids, saponins, alkaloids, and carbohydrates. No abnormal sign of symptoms were observed in any of the animal fed with aqueous and ethanol extracts at the dose rate of 300 mg/kg body weight, 2000 mg/kg body weight &amp; 5000 mg/kg body weight. No mortality was observed in any of the animals. Conclusion: M. oleifera barks, ethanol and aqueous extracts contain steroids and triterpenoids, saponins, alkaloids and carbohydrates. The administration of M. oleifera ethanolic and water extracts are safest &amp; has no adverse effect on growth related and biochemical parameters indicating its safety.

The Organization of Sleep in Krushinskii–Molodkina Rats after Sleep Deprivation and Audiogenic Convulsive Seizures of Different Intensities

The organization of sleep after audiogenic paroxysmal seizures of different intensities induced in animals with a normal daily sleep-waking cycle was studied in Krushinskii–Molodkina rats, which have an inherited predisposition to audiogenic convulsions; sleep organization was also studied after 12-h deprivation of fast-wave sleep on a platform or 6-h total sleep deprivation by waking. In all these conditions, intense audiogenic seizures with clonic or clonic-tonic convulsions produced long-lasting and significant disorders of sleep organization in rats, expressed predominantly as impairments to the functional mechanisms triggering the fast-wave phase of sleep. While paroxysmal seizures evoked after experimental sleep deprivation consisted only of motor arousal without any clear signs of convulsions, this type of seizure could even to some extent promote the faster onset of recovery after deprivation and did not induce functional disorganization of the brain system responsible for triggering and maintaining fast-wave sleep.

Carbamate poisoning in a dairy goat herd: Clinicopathological findings and therapeutic approach

CASE HISTORY: Approximately 1 hour after the consumption of carnations from a nearby glasshouse 55 animals from a dairy goat herd exhibited signs of possible poisoning. CLINICAL FINDINGS: Upon clinical examination affected animals exhibited signs of salivation, tympany, tachypnoea, polydipsia, urination, diarrhoea, bradycardia, miosis, tremor and convulsions. As poisoning from an acetylcholinesterase-inhibiting insecticide was suspected, treatment with atropine sulphate was initiated at a dose of 0.3 mg/kg bodyweight. The treatment was repeated for some animals that relapsed, and was effective in all cases, with the exception of one goat kid that died. DIAGNOSIS: Necropsy of the goat kid showed pulmonary oedema and congestion of internal organs. Toxicological analysis of stomach contents and liver of the dead animal, as well as of the carnations, revealed high concentrations of carbamates. CLINICAL RELEVANCE: Carbamate poisoning after consumption of polluted feedstuffs or glasshouse products can be fatal for dairy goats. Atropine sulphate, at 0.3 mg/kg, can be useful in treating this condition.

Acute toxicity studies of polyherbal formulation Methiorep Premix

An experimental study with the objective to evaluate the acute toxicity of polyherbal formulation Methiorep Premix (supplied by Ayurvet Ltd., Baddi, India), was done as per OECD guidelines 423. Methiorep is a scientifically developed combination of herbs that contains herbal ingredients rich in Methionine in free form as well as conjugated form. The study was done on 3 males and 3 female Wistar Albino rats which were administered an initial dose of 500 mg/kg body weight followed by 2000 mg/kg & 5000 mg/kg body weight. The animals were observed for signs of convulsions, tremors, circling, depression, excitement and mortality. Body weight was recorded at 0,7 th and 14 th day and plasma total protein, albumin; AST and ALT were measured to evaluate the toxicity of the preparation. No abnormal sign of symptoms were observed in any of the animal fed with Methiorep Premix at the dose rate of 500 mg/kg body weight, 2000 mg/kg body weight & 5000mg/kgbody weight. No mortality was observed in any of the animals indicating its safety.

The role of 5-HT 7 receptors in the control of seizures

Serotonin exerts its effects via at least 14 different receptor subtypes, but the role of only a few of them has been studied in relation to the control of seizures. A negative role of 5-HT 7 receptors has recently been proposed. To evaluate further in unstressed and stressed animals the possible role of this receptor subtype in the control of brain excitability, we treated mice with antagonists and agonists of these receptors prior to exposure to swim stress and the intravenous infusion of picrotoxin, a non-competitive GABA A receptor antagonist. In accordance with the previous studies, swim stress increased the doses of picrotoxin producing two convulsant signs (running/bouncing clonus, tonic hindlimb extension) and death, i.e., swim stress increased the seizure threshold for picrotoxin. SB-269970 (10–30 mg/kg ip), a selective antagonist of 5-HT 7 receptors, and ritanserin (1 mg/kg ip), a nonselective 5-HT 2/7 antagonist, failed to affect, while 5-carboxamidotryptamine (5-CT), a potent 5-HT 1/7 receptor agonist, increased in unstressed and swim-stressed mice the doses of picrotoxin producing convulsions and death. The anticonvulsant effect obtained with 5-CT 0.5 mg/kg was not greater than that obtained with 0.1 mg/kg. The 5-CT (0.1 mg/kg ip)-induced increase of the seizure threshold for picrotoxin in stressed mice was abolished with SB-269970 (10 mg/kg), but not with WAY-100635 (0.3 mg/kg), a selective antagonist of 5-HT 1A receptors, suggesting that the anticonvulsant effect of 5-CT against convulsions produced by picrotoxin was achieved via 5-HT 7 receptors. The results suggest a positive role of 5-HT 7 receptors in the control of seizures.