Autoradiographic ultrastructural observation on the meninges of the regenerating tail of lizards.

The formation of the meninges around the new spinal cord of the regenerating tail of the lizards Anolis and Lampropholis has been studied after injection of 3H-thymidine and 3H-proline. An optical and electron microscopic autoradiographical study revealed that many irregular 3H-thymidine labeled meningeal fibroblasts surround the apical regenerating spinal cord. Meningeal fibroblasts become flat at about 0.5-1 mm from the tail tip while they actively uptake 3H-proline involved in the synthesis of collagen and elastin. Elastic fibres are in intimate contact with the meningeal fibroblasts. One hour after injection of 3H-proline trace grains were seen most in the Golgi apparatus and secretory elastin-like vesicles. The importance of the elastic fibrils around the caudal spinal cord of lizard in relation to the body movements is discussed.