Influence of renal denervation on blood pressure, sodium and water excretion in acute total obstructive apnea in rats

Obstructive apnea (OA) can exert significant effects on renal sympathetic nerve activity (RSNA) and hemodynamic parameters. The present study focuses on the modulatory actions of RSNA on OA-induced sodium and water retention. The experiments were performed in renal-denervated rats (D; N = 9), which were compared to sham (S; N = 9) rats. Mean arterial pressure (MAP) and heart rate (HR) were assessed via an intrafemoral catheter. A catheter was inserted into the bladder for urinary measurements. OA episodes were induced via occlusion of the catheter inserted into the trachea. After an equilibration period, OA was induced for 20 s every 2 min and the changes in urine, MAP, HR and RSNA were recorded. Renal denervation did not alter resting MAP (S: 113 ± 4 vs D: 115 ± 4 mmHg) or HR (S: 340 ± 12 vs D: 368 ± 11 bpm). An OA episode resulted in decreased HR and MAP in both groups, but D rats showed exacerbated hypotension and attenuated bradycardia (S: -12 ± 1 mmHg and -16 ± 2 bpm vs D: -16 ± 1 mmHg and 9 ± 2 bpm; P < 0.01). The basal urinary parameters did not change during or after OA in S rats. However, D rats showed significant increases both during and after OA. Renal sympathetic nerve activity in S rats increased (34 ± 9%) during apnea episodes. These results indicate that renal denervation induces elevations of sodium content and urine volume and alters bradycardia and hypotension patterns during total OA in unconscious rats.

Redes, (en)traves e cercas : notas etnográficas de um conflito socioambiental

Esta dissertação pretende contribuir no debate sobre o conflito socioambiental existente no Campinho, situado no alto do morro da Fonte Grande, Vitória (ES), cenário de uma disputa, profundamente desigual em termos de poder político dos agentes humanos envolvidos, por um espaço urbano “verde” imprensado entre duas secções de uma área de proteção integral, em que habita um coletivo há gerações. Através da etnografia, procurei seguir atores humanos e não-humanos para entender as representações dos ambientalistas, gestores e técnicos ambientais bem como do coletivo, cujas perspectivas defendidas reiteram de um lado a oposição entre natureza e sociedade, consolidando políticas de reclusão (natural) e exclusão (social), e de outro a permanência e o pertencimento ao lugar, como guardiões atuantes de outro regime de relações entre humanos e não-humanos.