RESUMEN
Isolated perfused rat heart model was used to observe the protective effects of berbamine on myocardial ischemia/reperfusion injury. The hearts were significantly injured by 40 min global ischemia followed by 20 min reperfusion. Berbamine could significantly improve heart function, prevent ventricular fibrillation, reduce CK release, preserve Na,K-ATPase activity, and reduce Na+ gain and K+ loss during ischemia and Ca2+ overload during reperfusion. With the use of low temperature ESR technique, in hearts subjected to 40 min ischemia and 15 sec reperfusion, oxygen-centered free radical signals became much more intense. In the presence of berbamine, these signals decreased. Results showed that berbamine could alleviate myocardial ischemia/reperfusion injury. This effect might be due to: 1) preserved myocardial Na,K-ATPase activity and inhibition of sodium overload at the end of ischemia, which might further lead to attenuation of reperfusion-induced calcium overload, and 2) reduction of oxygen free radical generation during reperfusion.
Asunto(s)
Alcaloides/farmacología , Antiarrítmicos/farmacología , Bencilisoquinolinas , Corazón/efectos de los fármacos , Isquemia Miocárdica/prevención & control , Daño por Reperfusión Miocárdica/prevención & control , Animales , Calcio/metabolismo , Creatina Quinasa/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres , Frecuencia Cardíaca/efectos de los fármacos , Técnicas In Vitro , Masculino , Contracción Miocárdica/efectos de los fármacos , Miocardio/enzimología , Miocardio/metabolismo , Potasio/metabolismo , Ratas , Ratas Wistar , Sodio/metabolismo , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidoresRESUMEN
We tested the effect of the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenosine (EHNA) on ischemia-reperfusion injury in isolated perfused rat heart. In the ischemia-reperfusion group (n = 10), ventricular fibrillation occurred within 3 min of reperfusion after the 40-min ischemic period. The incidence of ventricular fibrillation was 90% with a mean duration of 3.15 +/- 0.97 (SE) min. Resting tension increased significantly. By contrast, the incidence of ventricular fibrillation after reperfusion in the EHNA-treated (5 microM) group (n = 10) was 20% (P less than 0.01), and the duration was 0.30 +/- 0.21 min (P less than 0.01). Resting tension was significantly lower and around the normal level in the EHNA-treated group (P less than 0.01). Contraction amplitude and heart rate recovered to nearly normal compared with the ischemia-reperfusion group (P less than 0.01). Coronary flow was greater in the EHNA-treated group (P less than 0.01). It is concluded that EHNA protects the heart, possibly by accumulation of adenosine that benefits the hearts and by blocking the xanthine oxidase pathway for free radical generation.
Asunto(s)
Adenina/análogos & derivados , Inhibidores de la Adenosina Desaminasa , Corazón/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Nucleósido Desaminasas/antagonistas & inhibidores , Adenina/farmacología , Animales , Circulación Coronaria/efectos de los fármacos , Corazón/efectos de los fármacos , Técnicas In Vitro , Masculino , Contracción Miocárdica/efectos de los fármacos , Daño por Reperfusión Miocárdica/complicaciones , Perfusión , Ratas , Ratas Endogámicas , Descanso , Fibrilación Ventricular/prevención & controlRESUMEN
We present results for antilambda and antiproton production in Au+Au collisions at 11.7 A GeV/c including spectra and extracted invariant yields for both species in central and peripheral collisions in the rapidity range 1.0
RESUMEN
An excitation function of proton rapidity distributions for different centralities is reported from AGS Experiment E917 for Au+Au collisions at 6, 8, and 10.8 GeV/nucleon. The rapidity distributions from peripheral collisions have a valley at midrapidity which smoothly change to distributions that display a broad peak at midrapidity for central collisions. The mean rapidity loss increases with increasing beam energy, whereas the fraction of protons consistent with isotropic emission from a stationary source at midrapidity decreases with increasing beam energy. The data suggest that the stopping is substantially less than complete at these energies.