The microvasculature of the lateral choroid plexus in the rat: a scanning electron microscopy study of vascular corrosion casts.

The three-dimensional microvascular structure of many organs can be adequately investigated only using the corrosion casting technique. We applied this method, consisting of an injection of low viscosity acrylic resin through the major vessels and the subsequent digestion of the organic component with strong alkali or acids, to the choroid plexus of the lateral ventricles in the rat, focusing on its structural vascular features. This approach allowed a qualitative morphological description of the choroid plexus of the lateral ventricles, revealing several aspects of their capillary architecture as well as the morphological details underlying its main functional activity, essential to cerebrospinal fluid turnover. Observation of the casts with scanning electron microscopy gave a detailed picture of the choroid plexus of the lateral ventricles of the rat and enabled us to distinguish four different regions, depending on the site that the lateral ventricles occupied: the anterior olfactory region, the main central region, the longer branch and the inferior horn. Each region mostly consisted of spiral capillaries and had specific characteristics. At high magnification, the casts revealed distinctive vascular specializations, such as numerous bulges regularly placed on the capillaries. This morphological investigation underpins a better comprehension of the pathological mechanisms involving the choroid plexus in the lateral ventricles.