Epilepsy is a neuronal disorder characterized by abnormal excitability of the brain, leading to seizures. Only around 66% of the epileptic patients respond adequately to treatment with existing conventional anticonvulsants, making it necessary to investigate new antiepileptic drugs. The growing research into natural products and their pharmacological properties has become increasingly promising, particularly in the study of essential oils, which are already widely used in popular culture for treating various diseases. The present study evaluated the anticonvulsant effects of Lippia origanoides essential oil (LOEO) (100 mg/kg i. p.) compared to diazepam (DZP) (5 mg/kg i. p.), and the combined administration of these two substances to control convulsions induced by pentylenetetrazol (PTZ) (60 mg/kg i. p.). This evaluation was carried out using 108 male Wistar rats, which were divided into two experiments. Experiment 1–Behavioral assessment: The animals were divided into 4 groups (n = 9): (I) saline solution + PTZ, (II) DZP + PTZ, (III) LOEO + PTZ, (IV) LOEO + DZP + PTZ. The convulsive behavior was induced 30 min after the administration of the tested anticonvulsant drugs, and the observation period lasted 30 min. Experiment 2- Electrocorticographic evaluation: The animals were divided into 8 groups (n = 9): (I) saline solution; (II) LOEO; (III) DZP; (IV) LOEO + DZP; (V) saline + PTZ, (VI) DZP + PTZ (VII) LOEO + PTZ, (VIII) LOEO + DZP + PTZ. PTZ was administered 30 min after LOEO and DZP treatments and electrocorticographic activity was assessed for 15 min. For the control groups, electromyographic recordings were performed in the 10th intercostal space to assess respiratory rate. The results demonstrated that Lippia origanoides essential oil increased the latency time for the appearance of isolated clonic seizures without loss of the postural reflex. The animals had a more intense decrease in respiratory rate when combined with LOEO + DZP. EEG recordings showed a reduction in firing amplitude in the LOEO-treated groups. The combining treatment with diazepam resulted in increased anticonvulsant effects. Therefore, treatment with Lippia origanoides essential oil was effective in controlling seizures, and its combination with diazepam may represent a future option for the treatment of difficult-to-control seizures.

Manganese (Mn²⁺) is an abundant chemical element in the earth’s crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals’ ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese.

Introduction: Aperema (Rhinoclemmys punctularia) is a South American semi-aquatic freshwater turtle characterized by a highly curved, dark brown to black carapace and is distributed across Central and South America. Climate change affects freshwater turtles in a number of ways, including temperature, hatchling sex, and survival.Methods: Therefore, we analyzed temperature variations in these turtles through electrocardiographic recordings, since studies on temperature variations in R. punctularia are limited.Results and discussion: Electrocardiography (ECG) is a highly relevant diagnostic tool as it allows for precise assessments of cardiac events and is non-invasive. The development of non-invasive ECG measurement methods is crucial for evaluating and maintaining the health of chelonian individuals during veterinary treatment or experimental procedure. Our findings revealed that heart rate is temperature-dependent, showing that lower environmental temperatures result in decreased heart rates. Therefore, we demonstrated through the electrocardiographic patterns observed during the experiment that a reduction in the ambient temperature to which Rhinoclemmys punctularia are exposed can modulate the conductivity and automaticity of cardiac cells, subsequently leading to a decrease in heart rate.

The species Kinosternon scorpioides (scorpion mud turtle) has potential for commercial farming in captivity. Restraint is a stressful factor that can cause fatal reactions. However, research on stress in Muçuãs is scarce. Therefore, electrocardiography (ECG) is relevant because it allows precise diagnoses of cardiac events. The results revealed an increase in heart rate and amplitude in both sexes, with higher heart rates in males and greater amplitude in females. The P-Q interval decreased in females and remained unchanged in males. The QRS interval did not show statistically significant differences, but there was a slight decrease in males. The Q-T interval decreased in females, while it did not show significant variations in males. These findings suggest that the variation in intervals and, consequently, heart rate occurs due to the regulation of the adrenergic pathway during periods of stress in turtles, mainly due to high concentrations of β-adrenergic receptors. Therefore, it was shown that both females and males experienced cardiovascular instability during restraint stress, with greater instability in males.

A mortality of bees (Apis mellifera) caused by fipronil intoxication, due to its indiscriminate use in crops, has long been attracting the scientific community’s attention, either due to its acute or residual effects. In this study, we assessed the cardiac activity as a biomarker of fipronil intoxication through electrophysiological recordings of bees. Eighteen foragers, from the apiary of EMBRAPA—Eastern Amazon (Belém-Pará), bees were previously anesthetized at low temperature (− 10 °C) for 5 min and properly restrained and fixed on a stereotaxic base, where electrodes were implanted. All these procedures were carried out within a Faraday cage. Eighteen bees were used in the study. Worker bees engaged in foraging activities were selected. The bees were divided into a control group and a group treated with fipronil at 0.025 mg/bee (n = 9). The recordings lasted for 4 min and were evaluated at 1-s intervals represented by the following letters: A = (2–3 s), B = (59–60 s), C = (119–120 s), D = (179–180 s), and E = (239–240 s). The results showed that fipronil reduced the frequency and intensity of cardiac activity, exhibiting rapidly evolving effects, and promoting a disruption of homeostasis in bee hemodynamics. Through the obtained data, it was observed variation in spike amplitude, with a loss of cardiac strength and magnitude of the electrical impulse in the bee’s heart during exposure to fipronil.