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We examined the role of cardiac atria in the renal response to sequential volume expansion and contraction, during and directly following water immersion. In immersed healthy volunteers (group 1, n = 9) atrial diameter, plasma levels of atrial natriuretic peptide (ANP), and natriuresis increased, whereas renal vascular resistance (RVR) and filtration fraction declined. Each parameter changed in an opposite direction postimmersion. An analysis of transglomerular dextran transport suggests that transglomerular hydraulic pressure difference (delta P) changed in parallel with filtration fraction. Baseline atrial diameter, plasma ANP, RVR, and filtration fraction were significantly elevated in nine recipients of denervated cardiac allografts (group 2). Atrial diameter and plasma ANP changed in parallel with group 1 during and after immersion. However, corresponding reciprocal changes in RVR were smaller and filtration fraction remained constant throughout. From transglomerular dextran transport, we compute that delta P increased progressively during and after immersion, suggesting predominant efferent arteriolar tone. The postimmersed state was associated also with enhanced sodium retention despite sixfold higher plasma ANP than in group 1. These findings are consistent with an effect of cardiac denervation to leave unopposed efferent sympathetic nervous traffic to the kidney. They suggest that the latter is an important modulator of the renal response to changing plasma volume in humans.

We update the list of reptiles of Venezuela, reporting a total of 370 species from the country (four of these exotic), arrangedin 122 genera (one exotic), 30 families and three orders. Introduced species and dubious or erroneous records are discussed.Taxonomic, nomenclatural and distributional comments are provided when required. Considering species of probableoccurrence in the country (known to occur in Colombia, Brazil and Guyana at localities very close to the Venezuelan border) and still undescribed taxa, we estimate that the total number of species in Venezuela could exceed 400.Se actualiza la lista de reptiles de Venezuela a un total de 370 especies (cuatro de ellas exóticas), pertenecientes a 122géneros (un exótico), 30 familias y tres órdenes. Se discuten las especies introducidas, los registros dudosos o erróneos yse proporcionan comentarios taxonómicos, nomenclaturales o de distribución en casos necesarios. Después de considerarlas especies de probable presencia en el país (registros conocidos cercanos a la frontera con Colombia, Brasil y Guyana) y los taxones aun no descritos, se estima que el número total de especies en Venezuela podría superar las 400 especies.