Effect of anisodamine on the microcirculation of the hydronephrotic kidney of rats

Anisodamine, an atropine analog, is widely used in China for treatment of acute circulatory shock but mechanisms of its action are not fully known. We investigated the effect of anisodamine on different renal vessels in the hydronephrotic kidney. Anisodamine was added to the tissue bath containing the kidney to produce increasing concentrations from 10(-8) to 10(-3) M. Anisodamine dilated the arcuate artery, interlobular artery and afferent arteriole in a dose dependent manner. The maximal dilation of 15 to 25% in these preglomerular vessels was attained at a concentration of about 10(-5) M. In contrast, the efferent arteriole constricted by about 55% in response to anisodamine. The glomerular blood flow increased by 15 and 40% at anisodamine concentrations of 10(-8) and 10(-5) M respectively. The renal vascular effect of anisodamine could be abolished by the dopamine receptor antagonist haloperidol. Our data indicate that anisodamine is a potent vasodilator of preglomerular renal vessels and that its effect is mediated by activation of the dopaminergic system. The action of anisodamine through a dopaminergic mechanism, as found in the hydronephrotic kidney, may also be involved in its antishock properties.