Acanthoscurria gomesiana spider-derived Mygalin in the prelimbic prefrontal cortex modulates neuropathic pain and depression comorbid

Depression has a high rate of comorbidity with neuropathic pain. This study aims to investigate the effect of Mygalin, an acylpolyamine synthesized from a natural molecule in the hemolymph of the Acanthoscurria gomesiana spider, injected into the prelimbic (PrL) region of the medial prefrontal cortex on chronic neuropathic pain and depression comorbidity in rats. To investigate that comorbidity, neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve in male Wistar rats. The biotinylated biodextran amine (BDA) bidirectional neural tract tracer was microinjected into the PrL cortex to study brain connections. Rodents were further subjected to von Frey (mechanical allodynia), acetone (cold allodynia), and forced swim (depressive-like behavior) tests. BDA neural tract tracer-labeled perikarya were found in the dorsal columns of the periaqueductal gray matter (dPAG) and the dorsal raphe nucleus (DRN). Neuronal activity of DRN neurons decreased in CCI rats. However, PrL cortex treatment with Mygalin increased the number of spikes on DRN neurons. Mygalin treatment in the PrL cortex decreased both mechanical and cold allodynia and immobility behavior in CCI rats. PrL cortex treatment with N-methyl-D-aspartate (NMDA) receptor receptors attenuated the analgesic and antidepressive effects caused by Mygalin. The PrL cortex is connected with the dPAG and DRN, and Mygalin administration into the PrL increased the activity of DRN neurons. Mygalin in the PrL cortex produced antinociceptive and antidepressive-like effects, and the NMDA agonist reversed these effects.

Assessment of neuropharmacological potential of low molecular weight components extracted from Rhinella schneideri toad poison

Studies on toad poison are relevant since they are considered a good source of toxins that act on different biological systems. Among the molecules found in the toad poison, it can be highlighted the cardiotonic heterosides, which have a known mechanism that inhibit Na+/K+-ATPase enzyme. However, these poisons have many other molecules that may have important biological actions. Therefore, this work evaluated the action of the low molecular weight components from Rhinella schneideri toad poison on Na+/K+-ATPase and their anticonvulsive and / or neurotoxic effects, in order to detect molecules with actions of biotechnological interest. Methods: Rhinella schneideri toad (male and female) poison was collected by pressuring their parotoid glands and immediately dried and stored at -20 °C. The poison was dialysed and the water containing the low molecular mass molecules (< 8 kDa) that permeate the dialysis membrane was collected, frozen and lyophilized, resulting in the sample used in the assays, named low molecular weight fraction (LMWF). Na+/K+ ATPase was isolated from rabbit kidneys and enzyme activity assays performed by the quantification of phosphate released due to enzyme activity in the presence of LMWF (1.0; 10; 50 and 100 µg/mL) from Rhinella schneideri poison. Evaluation of the L-Glutamate (L-Glu) excitatory amino acid uptake in brain-cortical synaptosomes of Wistar rats was performed using [3H]L-glutamate and different concentration of LMWF (10-5 to 10 µg/µL). Anticonvulsant assays were performed using pentylenetetrazole (PTZ) and N-methyl-D-aspartate (NMDA) to induce seizures in Wistar rats (n= 6), which were cannulated in the lateral ventricle and treated with different concentration of LMWF (0.25; 0.5; 1.0; 2.0; 3.0 and 4.0 µg/µL) 15 min prior to the injection of the seizure agent. Results: LMWF induced a concentration-dependent inhibition of Na+/K+-ATPase (IC50% = 107.5 μg/mL). The poison induces an increased uptake of the amino acid L-glutamate in brain-cortical synaptosomes of Wistar rats. This increase in the L-glutamate uptake was observed mainly at the lowest concentrations tested (10-5 to 10-2 µg/µL). In addition, this fraction showed a very relevant central neuroprotection on seizures induced by PTZ and NMDA. Conclusions: LMWF from Rhinella schneideri poison has low molecular weight compounds, which were able to inhibit Na+/K+-ATPase activity, increase the L-glutamate uptake and reduced seizures induced by PTZ and NMDA. These results showed that LMWF is a rich source of components with biological functions of high medical and scientific interest.(AU)

Neuroprotective properties of RT10, a fraction isolated from Parawixia bistriata spider venom, against excitotoxicity injury in neuron-glia cultures

L-Glutamate (L-Glu), the major excitatory neurotransmitter in the mammalian Central Nervous System (CNS), is essential to cognitive functions. However, when L-Glu is accumulated in large concentrations at the synaptic cleft, it can induce excitotoxicity that results in secondary damage implicated in many neurological disorders. Current therapies for the treatment of neurological disorders are ineffective and have side effects associated with their use; therefore, there is a need to develop novel treatments. In this regard, previous studies have shown that neuroactive compounds obtained from the venom of the spider Parawixia bistriata have neuroprotective effects in vitro and in vivo. In this sense, this work aimed to evaluate potential neuroprotective effects of fraction RT10, obtained from this spider venom, on primary cultures of neuron and glial cells subjected to glutamate excitotoxicity insults. Methods: Primary cultures of neurons and glia were obtained from the cerebral tissue of 1-day-old postnatal Wistar rats. After 7 days in vitro (DIV), the cultures were incubated with fraction RT10 (0.002; 0.02; 0.2 and 2 µg/µL) or riluzole (100 µM) for 3-hours before application of 5 mM L-Glu. After 12 hours, the resazurin sodium salt (RSS) test was applied to measure metabolic activity and proliferation of living cells, whereas immunocytochemistry for MAP2 was performed to measure neuronal survival. In addition, the cells were immunolabeled with NeuN and GFAP in baseline conditions. Results: In the RSS tests, we observed that pre-incubation with RT10 before the excitotoxic insults from L-Glu resulted in neuroprotection, shown by a 10% reduction in the cell death level. RT10 was more effective than riluzole, which resulted in a cell-death reduction of 5%. Moreover, qualitative analysis of neuronal morphology (by MAP2 staining, expressed as fluorescence intensity (FI), an indirect measure of neuronal survival) indicate that RT10 reduced the toxic effects of L-Glu, as shown by a 38 % increase in MAP2 fluorescence when compared to L-Glu insult. On the other hand, the riluzole treatment resulted in 17% increase of MAP2 fluorescence; therefore, the neuroprotection from RT10 was more efficacious. Conclusion: RT10 fraction exhibits neuroprotective effects against L-Glu excitotoxicity in neuron-glia cultured in vitro.(AU)

Evaluation of Thr6-bradykinin purified from Polybia occidentalis wasp venom in the choline uptake of mammal cortices.

CONTEXT: Thr6-bradykinin is a peptide found in the venom of social and solitary wasps. This kinin, along with other bradykinin-like peptides, is known to cause irreversible paralysis in insects by presynaptic blockade of cholinergic transmission. However, this activity has never been tested in mammals. OBJECTIVE: As such, the objective of this study was to evaluate the effect of Thr6-bradykinin on the cholinergic system of rats. MATERIALS AND METHODS: The peptide was isolated from the venom of the Neotropical social wasp Polybia occidentalis Olivier (Vespidae). After correct identification and quantification by ESI-MS and MS/MS, the peptide was tested in [14C]-choline uptake using rat cortical synaptosomes. Each uptake assay was accompanied by lactic acid dehydrogenase (LDH) activity measurement to evaluate synaptosome integrity in the presence of six increasing concentrations of BK or Thr6-BK (0.039, 0.156, 0.625, 2.500, 10.000 and 40.000 µM). RESULTS: Data revealed that neither BK nor Thr6-BK at any of the six concentrations tested (from 0.039 to 40.000 µM) affected [14C]-choline uptake in synaptosomes. Moreover, there was no increase in LDH in the supernatants, indicating that BK and Thr6-BK did not disrupt the synaptosomes. DISCUSSION AND CONCLUSION: In contrast to previous reports for the insect central nervous system (CNS), Thr6-BK had no effect on mammalian cholinergic transmission. Nevertheless, this selectivity for the insect CNS, combined with its irreversible mode of action may be relevant to the discovery of new sources of insecticides and could contribute to understanding the role of kinins in the mammalian CNS.

Extra group copulation in Alouatta caraya (Primates, Atelidae) living on an island of urban forest from southeast São Paulo, Brazil

Extra group copulations are rarely observed among the Alouatta genus, which lives in a fragmented area in Brazil. Here, we describe the second extra group copulation in A. caraya in literature, which was the first from Brazil. This happened in the southeast urban island forest, which measures 25 ha. In this forest there are two troops: one of them with thirteen howlers and the other with four. These howlers may be extinct in a few years since in the region there is only 3.89 % of native forests and high anthropic action due to agribusiness. We discuss the possible issues that led to the extra group copulation.(AU)

Cópulas extra grupo raramente são observados em animais do gênero Alouatta, que vivem em áreas fragmentadas do Brasil. Aqui, descrevemos a segunda cópula extra grupo em A. caraya na literatura, que foi a primeira do Brasil. Isso aconteceu na floresta ilha urbana sudeste, que mede 25 ha. Nesta floresta existem dois bandos: um deles com treze bugios e o outro com quatro. Estes bugios podem ser extintos em poucos anos, uma vez que na região há apenas 3,89% de florestas nativas e alta ação antrópica, devido ao agronegócio. Nós discutimos os possíveis aspectos que levaram à cópula extra grupo.(AU)

Extra group copulation in alouatta caraya (primates, atelidae) living on an island of urban forest from southeast São Paulo, Brazil

Extra group copulations are rarely observed among the Alouatta genus, which lives in a fragmented area in Brazil. Here, we describe the second extra group copulation in A. caraya in literature, which was the first from Brazil. This happened in the southeast urban island forest, which measures 25 ha. In this forest there are two troops: one of them with thirteen howlers and the other with four. These howlers may be extinct in a few years since in the region there is only 3.89 % of native forests and high anthropic action due to agribusiness. We discuss the possible issues that led to the extra group copulation.

Cópulas extra grupo raramente são observados em animais do gênero Alouatta, que vivem em áreas fragmentadas do Brasil. Aqui, descrevemos a segunda cópula extra grupo em A. caraya na literatura, que foi a primeira do Brasil. Isso aconteceu na floresta ilha urbana sudeste, que mede 25 ha. Nesta floresta existem dois bandos: um deles com treze bugios e o outro com quatro. Estes bugios podem ser extintos em poucos anos, uma vez que na região há apenas 3,89% de florestas nativas e alta ação antrópica, devido ao agronegócio. Nós discutimos os possíveis aspectos que levaram à cópula extra grupo.

C-Phycocyanin protects SH-SY5Y cells from oxidative injury, rat retina from transient ischemia and rat brain mitochondria from Ca2+/phosphate-induced impairment.

Oxidative stress and mitochondrial impairment are essential in the ischemic stroke cascade and eventually lead to tissue injury. C-Phycocyanin (C-PC) has previously been shown to have strong antioxidant and neuroprotective actions. In the present study, we assessed the effects of C-PC on oxidative injury induced by tert-butylhydroperoxide (t-BOOH) in SH-SY5Y neuronal cells, on transient ischemia in rat retinas, and in the calcium/phosphate-induced impairment of isolated rat brain mitochondria (RBM). In SH-SY5Y cells, t-BOOH induced a significant reduction of cell viability as assessed by an MTT assay, and the reduction was effectively prevented by treatment with C-PC in the low micromolar concentration range. Transient ischemia in rat retinas was induced by increasing the intraocular pressure to 120mmHg for 45min, which was followed by 15min of reperfusion. This event resulted in a cell density reduction to lower than 50% in the inner nuclear layer (INL), which was significantly prevented by the intraocular pre-treatment with C-PC for 15min. In the RBM exposed to 3mM phosphate and/or 100µM Ca(2+), C-PC prevented in the low micromolar concentration range, the mitochondrial permeability transition as assessed by mitochondrial swelling, the membrane potential dissipation, the increase of reactive oxygen species levels and the release of the pro-apoptotic cytochrome c. In addition, C-PC displayed a strong inhibitory effect against an electrochemically-generated Fenton reaction. Therefore, C-PC is a potential neuroprotective agent against ischemic stroke, resulting in reduced neuronal oxidative injury and the protection of mitochondria from impairment.

Effects of the Paratemnus elongatus pseudoscorpion venom in the uptake and binding of the L-glutamate and GABA from rat cerebral cortex.

L-Glu is the most important and widespread excitatory neurotransmitter of the vertebrates. Four types of receptors for L-glu have been described. This neurotransmitter modulates several neuronal processes, and its dysfunction causes chronic and acute diseases. L-Glu action is terminated by five distinct transporters. Antagonists for these receptors and modulators of these transporters have anticonvulsant and neuroprotective potentials, as observed with the acylpoliamines and peptides isolated from spiders, solitary and social wasp venoms. On the other hand, the major inhibitory neurotransmitter in mammalian nervous tissue is the GABA. Drugs that enhance GABA neurotransmission comprise effective approaches to protecting the brain against neuronal injury. Is this study, we demonstrate for the first time the inhibition of the [3H]L-glu binding to its specific sites in synaptosomal membranes from rat cerebral cortex, produced by 0.027 U of Paratemnus elongatus venom (EC50). The venom of P. elongatus changes Km and Vmax into the high affinity uptake of the L-glu and decreases Km and Vmax into the parameters of the GABA uptake from rat synaptosomes. This leads us to speculate on the possible presence of selective and specific compounds in this venom that act in L-glu and GABA dynamics, and therefore, that can serve as tools and new drug models for understanding these neurotransmissions.