[Interactions between Matricaria recutita and cisplatin on PTZ-induced seizure threshold in mice]

Studies have shown that chamomile contains significant amounts of essential amino acids and flavonoids. Moreover, the neuropathic effects of cisplatin have been reported in humans and different animal models. The purpose of this study was to investigate the interactions between hydroalcoholic extract of Matricaria recutita and cisplatin using the standard method of chemical seizure induced by pentylenetetrazole [PTZ] in mice. In this experimental study, 32 male mice were randomly selected into 4 groups [n=8 per group]. First group received normal saline; second group received Matricaria recutita hydroalcoholic extract [200 mg/kg, intraperitoneally]; third group received cisplatin [2 mg/kg, intravenously] and the fourth group hydroalcoholic extract of Matricaria recutita plus cisplatin, thereafter, the seizure threshold was determined for each group. The results of this study showed that PTZ-induced seizure threshold in control mice was 35.86 +/- 1.67 mg/kg and chamomile hydroalcoholic extract significantly increased the PTZ seizure threshold [P<0.0001], while seizure threshold in the cisplatin group significantly decreased [P<0.0001]. Moreover, simultaneous use of Matricaria recutita extract and cisplatin caused significant increase of seizure threshold [P<0.0001] in cisplatin taking group. Considering the existence of several types of antioxidants and flavonoids in Matricaria recutita that have antioxidant and anticonvulsant effects, the plant can be used to reduce the neuropathic effects of cisplatin

Neuroprotective effect of vitamin c against ptz induced apoptotic neurodegeneration in adult rat brain

The present study was designed to observe the effect of PTZ on expression of caspsae-3, and to evaluate the neuroprotective role of vitamin C [vit-C] against PTZ-induced apoptotic neurodegeneration in adult rat brain. We observed that administration of a single conclusive dose of pentylenetetrazol [PTZ 50mg/kg] in adults rats induced epileptic seizure and increased activation of caspase-3 and caused neuronal death. Further, rats were injected with vit-C [250 mg/kg] 30 min before PTZ injection. The protective effect of vit-C against PTZ-induced apoptotic neurodegeneration in adult rat brain was observed using Western blot analysis and Nissl staining. The results showed that conclusive dose of PTZ-induced seizure, increased expression of caspase-3 and neuronal apoptosis in adult rat brain. Whereas, the pretreatment of vit-C along with PTZ showed significantly decreased expression of caspase-3 as compare to control group. Finally, our results indicated that vit-C can prevent some of the deleterious effect of seizure and neuronal degeneration induced by PTZ in adult rat brain

[Effect of progesterone administration in newborns rats on pentylenetetrazol kindling susceptibility after maturity]

Regarding the high prevalence of epileptic seizures, its complications and the necessity to control them, this study was carried out in order to assess the role of progesterone administration in newborn rats on Pentylenetetrazol [PTZ] kindling susceptibility after maturity. This experimental study was carried out on 32 newborn Wistar rats. Rats were randomly divided into four groups, which are as follows: progesterone-injected females, progesterone-injected males, sesamoid-injected females and sesamoid-injected males. Progesterone and sesamoid groups were injected with progesterone [100 mg/Kg] and sesamoid [100 mg/Kg] respectively. Sixty days after injection chemical kindling in the rats was analyzed by PTZ administration. Progesterone significantly increased the susceptibility for PTZ kindling in female rats however; it did not have a significant effect on seizure parameters in male rats. The results of this study suggest that chronic administration of progesterone can only increase susceptibility for chemical kindling in female rats and not in the males

Neuropharmacological actions of panchagavya formulation containing Emblica officinalis Gaerth and Glycyrrhiza glabra Linn in mice.

A panchagavya Ayurvedic formulation containing E. officinalis, G. glabra, and cow's ghee was evaluated for its effect on pentobarbital-induced sleeping time, pentylenetetrazol-induced seizures, maximal electroshock-induced seizures, spontaneous motor activity, rota-rod performance (motor coordination) and antagonism to amphetamine in mice. The formulation (300, 500 mg/kg, po) produced a significant prolongation of pentobarbital-induced sleeping time and reduced spontaneous locomotor activity. The formulation also significantly antagonised the amphetamine induced hyper-locomotor activity (500, 750 mg/kg, po) and protected mice against tonic convulsions induced by maximal electroshock (500, 750 mg/kg, po). The formulation slightly prolonged the phases of seizure activity but did not protect mice against lethality induced by pentylenetetrazole. The formulation did not show neurotoxicity. The results suggest that the panchagavya formulation is sedative in nature.

Alteration of pentylenetetrazole-induced kindling parameters by pretreatment of rats with propylthiouracil and lead acetate

Lead is known to be a potent neurotoxin that can cause seizure activity in humans and animals. Also, epileptic type convulsion is a known complication of hypothyroidism. This study was performed to determine the effect of propylthiouracil [PTU]-induced hypothyroidism and chronic lead exposure on pentylenetetrazol [PTZ]-induced kindling parameters. The test was carried out by using male albino rats weighing 180-230 g which were divided into four groups as follows: Group 1: rats which received distilled water for 25 days [control group]; Group 2: rats pretreated with an orally administered lead acetate solution [0.05%] for 25 days; Group 3: rats rendered hypothyroid with PTU solution [0.1% W/ V] for 25 days; and Group 4: rats co-treated with lead acetate solution [0.05% W/ V] and PTU solution [0.1% W/V] for 25 days. On the 26th day of the experiment PTZ [ip, 30 mg/kg] was injected once a day in order to induce seizure behaviors. Kindling parameters such as seizure latency, index, stage and frequency were evaluated. In animals, both lead acetate [0.05% W/ V] and PTU [0.1% W/ V] pretreatment caused significant alterations in kindling parameters separately. But in animals pretreated with a combination of lead acetate and PTU, potentiation of kindling parameters was not observed compared to groups one and two. In conclusion, lead acetate and PTU may affect kindling parameters by different mechanisms

Pharmacodynamic interactions of cypermethrin and centrally acting drugs in mice.

Cypermethrin a widely used insecticide of Pyrethroids (type II) group, was administered in mice at two dose levels (1/10 of LD50 i.e. 2.5 mg/kg and 1/5 of LD50 i.e. 5.0 mg/kg) and pharmacodynamic interactions of insecticide were studied with centrally acting drugs viz. pentobarbital sodium, amphetamine, pentylenetetrazole, acepromazine and analgin. Cypermethrin pretreatment potentiated the actions of pentobarbital and pentylene-tetrazole as evidenced by an increase in pentobarbital induced hypnosis and duration of pentylene-tetrazole induced chemoshock seizures. Tranquilizing action of acepromazine was potentiated but there was decrease in amphetamine influenced locomotor activity at both the dose levels. Cypermethrin pretreatment, however, did not have any pharmacodynamic interaction with analgin.

Cardiorespiratory alterations produced by pharmacological agents applied to the ventrolateral medulla (intermediate area) of the cat: effect of exercise condition on glycine-induced inhibition

1. To study the action of the intermediate area (IA), coextensive with the rostral ventrolateral medulla, on the neurophysiological mechanisms involved in the regulation of respiration, in terms of inspiratory drive and respiratory timing, cats were submitted to topical application of sodium pentobarbital (30 mg/ml), leptazol (200 mg/ml), glutamate (50 mg/ml) and glycine (100 and 50 mg/ml) to the IA. The effects of electrically induced exercise on the ventilatory response and oxygen uptake (VO2) obtained by topical application of glycine (50 mg/ml) to the IA were also studied. 2. Leptazol reduced minute ventilation (VE) and inspiratory drive (VT/TI) and changed the timing mechanism. Glutamate only increased tidal volume (VT), VE and VT/TI. Arterial blood pressure (AP) increased and heart rate (HR) did not change with either drug. 3. Sodium pentobarbital reduced VT and changed the timing mechanism. Glycine only reduced VE, VT and VT/TI. AP decreased and HR did not change with either drug. 4. The depressor effects of glycine on respiratory pattern, VO2 and CO2 production (VCO2) tended to be attenuated by exercise. 5. The fall in AP due to glycine application did not differ between resting and exercise conditions. 6. Our results indicate that at least two different nervous structures are involved in the IA: one responsible for the respiratory drive and sensitive to glycine and glutamate, and the other responsible for the regulation of the timing mechanism and sensitive to sodium pentobarbital and leptazol

Atividade depressora do sistema nervoso central da iangambina / Depressant activity of central nervous system of iangambina

Neste estudo, os autores relatam os dados da avaliaçao dos efeitos a nível do sistema nervoso central da iangambina, uma lignana furofurânica isolada da Ocotea duckei Vattimo. Os principais efeitos observados em camundongos, foram: potencializaçao do tempo de sono induzido por pentobarbital e bloqueio das convulsoes induzidas por pentilenotetrazol.

Estudo da açäo do suco extraído das folhas de Bryophyllum calycinum salisb (Crassulaceae) sobre o sistema digestivo / Study of the action of the juice extracted from Bryophyllum calycinum salisb (Crassulaceae) on the gabaergic system

Bryophyllum calycinum Salisb. (Crassulaceae) é uma planta largamente utilizada em regiöes tropicais e subtropicais. Seu principal uso consiste como uma medicaçäo tópica em afecçöes cutâneas de natureza alérgica. (NASSIS, 1991) (16) demonstrou ser o suco extraido desta planta um potente antagonista dos receptores H-1 a nível periférico em ratos. Um trabalho subsequente (NASSIS et al, 1991) (17) mostrou que o suco extraído da Crassulaceae tem uma depressora no SNC. O presente estudo teve por objetivo a investigaçäo de uma eventual açäo GABAérgica do suco. A partir dos resultados obtidos pudemos concluir que o suco näo apresenta atividade sobre o sistema GABAérgico

Effect of subacute insecticide exposure on body weight, drug responses & electrical convulsions in mice.

Effect of subacute insecticide exposure was studied in male albino mice treated with phosphamidon, propoxur or aldrin at 1/40 LD50 dose intraperitoneally daily for 8 wk. The parameters studies included body weight, pentobarbitone (50 mg/kg) sleeping time, chlorpromazine (6 mg/kg) induced motor incoordination and convulsions induced by leptazol (100 mg/kg) and electrical stimulation (18 mA for 0.2 msec). While body weight and electrically induced convulsions were not affected, the effect of various drugs was significantly decreased. The observed changes may be due to the induction of hepatic drug metabolising enzymes by the insecticides. The study suggests that certain dose adjustment of drugs may be necessary in those exposed to insecticides over long periods.

Efeitos do alfatesin sobre a atividade convulsivante da estricnina e do pentetrazol em coelhos / Effects of alphatesin on the convulsive activity of the strichinin and pentetrazol in rabbits

O uso de Alfatesin é acompanhado com freqüência de fenômenos excitatórios de natureza ainda näo esclarecida apesar de ser empregado, eventualmente, em crises de epilepsias. Por esse motivo resolvemos estudar os efeitos desse agente, isoladamente (0,1 kg1) e em associaçäo com pentetrazol (10 mg. kg-1) ou 0,1 ml de estricnina (0,2 mg.kg-1) por via venosa, em dez coelhos. As drogas foram utilizadas isoladamente e em associaçäo nos mesmos animais, em intervalos de quatro dias. Foram observadas: presença de reflexo córneo palpebral e de endireitamento, nistagmo, miose, tono muscular, ataxia, analgesia e convulsäo. A cada atributo foi conferida uma nota de 0 a 3, de acordo com a sua intensidade. Foi observado que o alfatesin, isoladamente, determina sedaçäo, hipotonia muscular, ataxia e perda do reflexo de endireitamento, mas näo induz analgesia. Associado ao pentetrazol e a estricnina reduz ou abole as manifestaçöes de estimulaçäo do sistema nervoso central características dessas drogas. Ainda é capaz de impedir o óbito induzido pela estricnina isoladamente. A explicaçäo para esses efeitos é discutida, necessitando de estudos mais sofisticados para seu esclarecimento

A Study of the Mechanism on Hibernation

The present study was performed in order to test the effects of diphenylhydantoin (DPH) and two central nervous system (CNS) stimulants, intermittent light stimulation(ILS) and pentylenetetrazol (Metrazol) on body temperature (Tb) during cold exposure in the bat DHP delayed the onset of entry into hibernation in both the oriental discoloured bats and the little brown bats and formed long and prominent plateaus that were not found in the normal and the controls. The responses of body temperature to the ILS were sensitive and the body temperature fell dramatically in the big brown bats. Metrazol effects on body temperature were obvious but; seemed dose-dependent. The experimental results further support the hypothesis that hibernation is an epileptic fit as suggested by serveral researchers.