Protein-caloric dietary restriction inhibits mossy fiber sprouting in the pilocarpine model of TLE without significantly altering seizure phenotype.

Given the known effects of undernutrition over protein synthesis, we promoted neonatal undernutrition to evaluate its effect over the neuroplasticity induced by the pilocarpine model of epilepsy and also over spontaneous seizure expression. A well-nourished group (WN), fed ad libitum rat chow diet, and an undernourished group (UN), fed 60% of the amount of diet consumed by a WN group, were submitted to status epilepticus (SE) through pilocarpine injection at 45 days of age. Thereafter, animals were behaviorally monitored for 6h daily to quantify seizures.

The role of dorsomedial hypotalamus ionotropic glutamate receptors in the hypertensive and tachycardic responses evoked by Tityustoxin intracerebroventricular injection.

The scorpion envenoming syndrome is an important worldwide public health problem due to its high incidence and potential severity of symptoms. Some studies address the high sensitivity of the central nervous system to this toxin action. It is known that cardiorespiratory manifestations involve the activation of the autonomic nervous system.

Effects of tityustoxin on cerebral inflammatory response in young rats.

Accidents caused by scorpion stings, mainly affecting children, are considered an important cause of morbidity and mortality in tropical countries. Clinical studies demonstrate the relevant role of systemic inflammatory events in scorpion envenoming. However, remains poorly understood whether the major lethal component in Tityus serrulatus venom, tityustoxin (TsTX), is able to induce inflammatory responses in the cerebral microcirculation.

Effects of Tityus serrulatus scorpion venom on thromboelastogram in rats.

Thromboelastometry was used to evaluate blood coagulation in anesthetized rats after intravenous administration of Tityus serrulatus scorpion venom (Tx). Tracheostomy followed by catheterization of the left jugular vein and right carotid artery were performed for Tx or Ringer's lactate solution injection and blood sample harvesting, respectively. Blood samples were obtained at the beginning of the experiments (baseline) and at two, five, 15, 30, and 60 min after intoxication.

Brainstem structures are primarily affected in an experimental model of severe scorpion envenomation.

Severe scorpion envenoming (SSE) is more frequent in children and is characterized by systemic dysfunctions with a mortality rate of up to 9%. Recent evidence shows that the central nervous system (CNS) plays a key role in triggering the cascade of symptoms present in SSE. The age-dependent role of the CNS in SSE lethality may be summarized in 3 hypotheses: (1) the shown increased blood brain barrier permeability of infants to the toxins would especially and primarily compromise neurovegetative control areas, (2) the neurons within these areas have high affinity to the toxins, and (3) the neurovascular interaction is such that SSE metabolically compromises proper function of toxin-targeted areas.

Malnutrition alters the cardiovascular responses induced by central injection of tityustoxin in Fischer rats.

Scorpion envenoming and malnutrition are considered two important public health problems in Brazil, involving mainly children. Both these conditions are more common among the economically stratified lower income portion of the population, thus suggesting that these factors should be analyzed concomitantly. It is known that cardiorespiratory manifestations, as cardiac arrhythmias, arterial hypertension and hypotension, pulmonary edema and circulatory failure are the main "causa mortis" of scorpion envenomation.

Malnutrition during central nervous system growth and development impairs permanently the subcortical auditory pathway.

The brain that grows and develops under the continued influence of malnutrition presents permanent impairment on functioning and neurotransmitter release. The aim of this study was to investigate the chronic effects of neonatal food restriction on neurochemical and neurodynamical aspects within the primary auditory sensory pathway. Our working hypothesis is that neonatal malnutrition may affect the flow of primary sensory information both at a neurochemical and neurodynamical level.

Chronic coffee and caffeine ingestion effects on the cognitive function and antioxidant system of rat brains.

Coffee is a popular beverage consumed worldwide and its effect on health protection has been well studied throughout literature. This study investigates the effect of chronic coffee and caffeine ingestion on cognitive behavior and the antioxidant system of rat brains. The paradigms of open field and object recognition were used to assess locomotor and exploratory activities, as well as learning and memory.

Effects induced by Apis mellifera venom and its components in experimental models of nociceptive and inflammatory pain.

The effects induced by Apis mellifera venom (AMV), melittin-free AMV, fraction with molecular mass < 10 kDa (F<₁₀) or melittin in nociceptive and inflammatory pain models in mice were investigated. Subcutaneous administration of AMV (2, 4 or 6 mg/kg) or melittin-free AMV (1, 2 or 4 mg/kg) into the dorsum of mice inhibited both phases of formaldehyde-induced nociception. However, F<₁₀ (2, 4 or 6 mg/kg) or melittin (2 or 3 mg/kg) inhibited only the second phase.

Effect of coffee on chemical hepatocarcinogenesis in rats.

The aim of this study was to investigate the effect of daily coffee ingestion on hepatocarcinogenesis in rats submitted to the resistant hepatocyte (RH) model. During lactation, the dams were fed a control or a coffee-supplemented diet. After weaning, male pups followed the same dietary protocol and were submitted to the RH model.

Electroencephalographic evidence of brainstem recruitment during scorpion envenomation.

Scorpion envenomation is a public health problem in Brazil, with most severe cases occuring in children under the age of 5 years (0.6% lethality). In fact, the toxic fractions of the Tityus serrulatus scorpion venom (TSSV) have greater permeability across the BBB of weanling rats when compared to adults.

Carbamazepine is effective in the treatment of 21-day-old Wistar rats injected with Tityus serrulatus crude venom.

The scorpion-envenoming syndrome has an incidence of approximately 8000 accidents/year in Brazil; with most severe cases occurring during childhood and elderly. Previous results from our laboratory suggest that the effects of scorpion toxins on the central nervous system play a major role on the lethality induced by scorpion envenoming. Our group has shown that the pre-treatment with carbamazepine (CBZ) is able to increase the latency-to-death in developing animals inoculated with tityustoxin, a toxic fraction of the Tityus serrulatus crude venom.

Dose-dependent effect of carbamazepine on weanling rats submitted to subcutaneous injection of tityustoxin.

The scorpion envenoming syndrome is a serious public health matter in Brazil. The most severe cases occur during childhood and elderly. Previous results from our laboratory suggest that the effects of scorpion toxins on the central nervous system play a major role on the lethality induced by scorpion envenoming.

Carbamazepine protects the CNS of Wistar rats against the central effects of scorpion envenomation.

The scorpion envenoming syndrome is a serious public health matter in Brazil. Previous results from our laboratory suggest that the effects of scorpion toxins on the central nervous system play a major role on the lethality induced by scorpion envenoming. The objective of this work is to evaluate carbamazepine (CBZ) as a potential therapeutic agent against tityustoxin (TsTX) envenomation.

Effect of acid secretion blockade on acute gastric mucosal lesions induced by Tityus serrulatus scorpion toxin in anaesthetized rats.

Scorpion venom (TX) promotes gastric acid and pepsin secretion leading to acute gastric mucosal lesions (AGML), when injected in animals. The goal of the present study was to observe the effects of acid gastric secretion blockers over the incidence of TX-induced AGML in vivo. To verify this model, we used male albino rats, fasted 18-20 h (n=122) and anaesthetized with urethane (1.

Pharmacological investigation of the nociceptive response and edema induced by venom of the scorpion Tityus serrulatus.

In this study we characterized the nociceptive response and edema induced by the venom of the scorpion Tityus serrulatus in rats and mice and carried out a preliminary pharmacological investigation of the mechanisms involved in these responses. Intraplantar injection of the venom (1 or 10mug) induced edema and a marked ipsilateral nociceptive response, characterized by thermal and mechanical allodynia and paw licking behaviour. The nociceptive response was inhibited by previous intraperitoneal administration of indomethacin (4mg/kg), dipyrone (200mg/kg), cyproheptadine (10mg/kg) or morphine (5 or 10mg/kg), but not by dexamethasone (1 or 4mg/kg) or promethazine (1 or 5mg/kg).

Dopamine release evoked by beta scorpion toxin, tityus gamma, in prefrontal cortical slices is mediated by intracellular calcium stores.

1. We have investigated the effect of tityus gamma (TiTX gamma) scorpion toxin on the release of [3H]dopamine in rat brain prefrontal cortical slices. The stimulatory effect of TiTX gamma on the release of [3H]dopamine was dose/time-dependent with an EC50 of 0.

Effects of alpha-scorpion toxin, tityustoxin on the release of [3H] dopamine of rat brain prefrontal cortical slices.

The effect of tityustoxin (TsTX) on the release of [3H] dopamine in rat brain prefrontal cortical slices was investigated. The stimulatory effect of TsTX was dependent on incubation time and TsTX concentration with an EC50 of 0.05 microM.

Effect of age on body distribution of Tityustoxin from Tityus serrulatus scorpion venom in rats.

Previous research from our Laboratory has shown a greater susceptibility of young animals, when compared to adults, to envenomation by tityustoxin (TsTX), one of the main toxins from Tityus serrulatus scorpion venom. Our hypothesis is that a differential body distribution of TsTX among adult and young animals could account for the worse prognosis of scorpion envenomation in infants. Thus, TsTX labeled with technetium-99m was injected (6 microg, subcutaneous) in adult (150-160 day-old) and young (21-22 day-old) male rats.

Centrally injected tityustoxin produces the systemic manifestations observed in severe scorpion poisoning.

In this work we submitted adult male Wistar rats to intracerebroventricular (icv) and iv microinjections of the fraction tityostoxin (TsTX) from the Tityus serrulatus scorpion venom, to address whether the CNS could account for the systemic alterations previously reported: cardiac arrhythmias, lung edema, and seizures. Animals were injected icv, total volume of 1.0 microl, with either sterile saline (n = 4) or differing doses of TsTX (1.

Modulation of Na+-channels by neurotoxins produces different effects on [3H]ACh release with mobilization of distinct Ca2+-channels.

1. Voltage-gated Na+ channels are responsible for initiation and conduction of action potentials. The arrival of an action potential at nerve terminal increases intracellular Na+ and Ca2+ concentrations.

Cardiovascular and respiratory interactions of hyperosmolar saline, scorpion toxin, and veratridine in rats.

This study evaluates the cardiovascular and respiratory effects evoked by hypertonic sodium chloride solution (HSS) and the possible interactions of these effects with scorpion toxin (TX) or veratridine (V). Groups 1 (1 mL/kg, rapid), 2 (4 mL/kg, rapid), and 3 (4 mL/kg, slow) were used for comparison of HSS administered by rapid or slow injection. HSS (4 mL/kg) was injected after bilateral vagotomy (group 4) or administration of atropine (group 5).

Phenobarbital blocks the lung edema induced by centrally injected tityustoxin in adult Wistar rats.

The aim of this study was to evaluate the ability of phenobarbital to block the lung edema observed after intracerebroventricular (icv) injections of tityustoxin (TsTX), a toxic fraction of the Tityus serrulatus venom. We injected 1.74 microg icv (1.

Tracking sodium channels in live cells: confocal imaging using fluorescently labeled toxins.

One particularly important class of ion channels in excitable cells are the voltage-dependent sodium channels (VDSC). Knowledge of the distribution of VDSC in living cells is important for studies of neuronal excitability, development, and plasticity. Here, we demonstrate a new method for visualizing the spatial distribution of VDSC in living cells.