SEM [scanning electron microscopy] of the tubules of the hepatopancreas and the stomach gland of the scorpion (Buthus quinquestriatus): a methodological study

Different procedures were tested for the purpose of circumventing the technical obstacles encountered in SEM of the scorpion hepatopancreas and stomach gland. These problems are caused by the relatively high osmotic pressure of the body fluid of this animal, the irregular surface contour, and the very high content of fat in the organs under investigation. The best results were obtained following glutaraldehyde fixation at an effective osmotic pressure approaching that of scorpion body fluid, ensuring stabilization of fat by post‐fixation in osmium tetroxide, and overcoming the charge effects via the OTOTO (Osmium‐Thiocarbohydrozide) method in combination with metal coating. Dehydration by CPD or FD both gave rise to inevitable artefacts (shrinkage or cracking). Used together, however, CPD and FD were complementary. The surfaces of hepatopancreatic and stomach gland tubules showed a distinct similarity. Tubules of both organs were lined mostly with cells equipped with parallel arrays of microvilli on the apical surface and containing large amounts of fat.