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This study describes the natural poisoning of goats by Rhododendron simsii in Southern Brazil. Five of eight goats died after ingesting branches of plants, which were pruned and placed near the goats. Clinical signs observed were restlessness, shrill bleating, profuse regurgitation, looking and kicking at the flank, a loss of balance, irregular gait, staggering, and opisthotonos. At necropsy or histopathology affected goats had not showed lesions. Two goats were fed with 21.5g kg-1 bw and 30g kg-1 bw of fresh leaves of R. simsii. Both goats developed signs similar to those naturally affected goats. These findings indicated that R. simsii is highly toxic and lethal to goats.
Descreve-se um surto de intoxicação espontânea por R. simsii em caprinos no sul do Brasil. Cinco de oito cabras morreram após a ingestão da planta que foi podada e colada no local onde estavam os caprinos. Os sinais clínicos caracterizam-se por excitação, balidos estridentes, regurgitação, coicear o flanco, desequilíbrio e opistótono. Não foram observadas lesões macroscópicas e histológicas nos animais necropsiados. Dois animais receberam doses de 21,5 e 30g kg-1 de folhas verdes de R. simsii. Ambos desenvolveram sinais clínicos similares aos animais intoxicados espontaneamente. Esses achados indicam que R. simsii é altamente tóxica e letal para caprinos.
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Objective: To study the effect of endothelium-derived hyperpolarizing factor (EDHF)-mediated responses of relaxation and hyperpolarization of vascular smooth muscle cell (VSMC) of rat cerebral basilar artery (CBA) subjected to cerebral ischemia/reperfusion (I/R) to total flavones in rhododendra (TFR). Methods: The model of global cerebral I/R in rats was made by 4-vessel occlusion (4-VO). The vasodilation and resting membrane potential (RMP) of VSMC of rat CBA were detected in vitro. Results: In the presence of 3×10-5 mol/L Nω-nitro-L-arginine-methyl-ester (L-NAME, an inhibitor of nitric oxide synthase) and 1×10-5 mol/L Indomethacin (Indo, an inhibitor of PGI2 synthesis), the global cerebral I/R markedly enhanced 1×10-7-1×10-5 mol/L acetylcholine (Ach)-elicited relaxation and hyperpolarization of RMP of VSMC in rat CBA. In the presence of L-NAME and Indo, 11-2 700 mg/L TFR induced significant and dose-dependent hyperpolarization of RMP of VSMC and relaxation of rat CBA subjected to global cerebral I/R. The hyperpolarization and relaxation were obviously inhibited by tetraethylammonium (an inhibitor IKCa at 1 mmol/L) and 1×10-4 mol/L dl-propargylglycine (PPG), an inhibitor of endogenous hydrogen sulfide (H2S) synthase. Conclusion: Global cerebral I/R could enhance the non-NO-non-PGI2-mediated responses of hyperpolarization and vasorelaxation in rat CAB. In rat CAB subjected to global cerebral I/R, TFR could significantly induce this non-NO-non-PGI2 hyperpolarization and relaxation, the so-called EDHF response that might be mediated by endogenous H2S.
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Objective To study the protective effect of total flavone from Rhododendron simsii(TFRS) on myocardial ischemia-reperfusion injury rats and its mechanism.Methods The ischemic model was made by occluding the anterior descending of the left artery(LAD) in rats.The change of ST segment and T wave of electrocardiograph(ECG) were observed,and the activity of lactate dehydrogenase(LDH),creatine kinase(CK),levels of the maleic dialdehyde(MDA),and nitric oxide(NO) in serum were measured.And by tetrazolium chloride(TTC) staining,the areas of myocardial infarction were observed.The expression of inducible nitricoxide synthase(iNOS) in rats was detected by emploring the reverse transcription-polymerase chain reaction(RT-PCR) technique.Results On the myocardial infarction model by occluding the anterior descending of the LAD in rats,TFRS(100 mg/kg) obviously reduced the height of ST segment after occluding 30 min and TFRS(25,50,and 100 mg/kg) obviously reduced the height of ST segment after reperfusion 30 min.TFRS(50 mg/kg) reduced by myocardial infarction area.TFRS(50 and 100 mg/kg) obviously reduced the activity of CK and LDH.TFRS(50 mg/kg) decreased the level of MDA in serum.By RT-PCR technique,it was found that the expression of iNOS mRNA in myocardium in IR rats pretreated with TFRS(100 mg/kg) was higher than that in IR and normal groups.Conclusions TFRS has the significant protection against myocardial ischemia-reperfusion injury via atte-nuating oxygen free radical and increasing the expression of iNOS mRNA and NO production.