Angiogenic activity of latex from Euphorbia tirucalliLinnaeus 1753 (Plantae, Euphorbiaceae) / Atividade angiogênica do látex da Euphorbia tirucalliLinnaeus 1753 (Plantae, Euphorbiaceae)

AbstractTo assess the pro-angiogenic activity of Euphorbia tirucalli, commonly known as “avelós” plant, we performed a series of tests by applying an aqueous E. tirucalli latex solution (10 mg/mL) to the chorioallantoic membranes (CAMs) of 80 fertilized chicken eggs incubated in a temperature- and humidity-controlled automatic incubator. The results indicated that the aqueous latex solution increased vascular network formation compared to that with the negative control (p < 0.05) and the inhibitor control (p < 0.05). This suggests that under the experimental conditions tested, the aqueous latex solution induced an inflammatory response leading to neoangiogenesis.

ResumoCom o objetivo de analisar a atividade angiogênica apresentada pela Euphorbia tirucalli, popularmente conhecida comumente como “avelós”, foram realizados ensaios utilizando solução aquosa de látex na concentração de 10 mg/ml, aplicada em membrana corioalantóide (MCA) de 80 ovos férteis de galinha, incubado em estufa automática com temperatura e umidade controladas. Os resultados apontaram que a ação da solução aquosa provocou aumento da percentagem da rede vascular formada em relação aos controles negativo (p<0,05) e inibidor (p<0,05), indicando que nas condições deste experimento, foi responsável pela ativação da resposta inflamatória e crescimento de novos vasos sanguíneos.

Involvement of midbrain tectum neurokinin-mediated mechanisms in fear and anxiety

Electrical stimulation of midbrain tectum structures, particularly the dorsal periaqueductal gray (dPAG) and inferior colliculus (IC), produces defensive responses, such as freezing and escape behavior. Freezing also ensues after termination of dPAG stimulation (post-stimulation freezing). These defensive reaction responses are critically mediated by γ-aminobutyric acid and 5-hydroxytryptamine mechanisms in the midbrain tectum. Neurokinins (NKs) also play a role in the mediation of dPAG stimulation-evoked fear, but how NK receptors are involved in the global processing and expression of fear at the level of the midbrain tectum is yet unclear. The present study investigated the role of NK-1 receptors in unconditioned defensive behavior induced by electrical stimulation of the dPAG and IC of male Wistar rats. Spantide (100 pmol/0.2 μL), a selective NK-1 antagonist, injected into these midbrain structures had anti-aversive effects on defensive responses and distress ultrasonic vocalizations induced by stimulation of the dPAG but not of the IC. Moreover, intra-dPAG injections of spantide did not influence post-stimulation freezing or alter exploratory behavior in rats subjected to the elevated plus maze. These results suggest that NK-1 receptors are mainly involved in the mediation of defensive behavior organized in the dPAG. Dorsal periaqueductal gray-evoked post-stimulation freezing was not affected by intra-dPAG injections of spantide, suggesting that NK-1-mediated mechanisms are only involved in the output mechanisms of defensive behavior and not involved in the processing of ascending aversive information from the dPAG.