The "third eye"-- a new concept of trans-differentiation of pineal gland into median eye in amphibian tadpoles of Bufo melanostictus

Indian J Exp Biol. 2005 Aug;43(8):671-8.


Median third eye was found to develop from transplanted pineal gland of external gill stage tadpoles in the recipient 5 toe stage tadpoles of Bufo melanostictus. Pineal gland along with a bit part of brain tissue of the donor external gill stage tadpole was cut out and transplanted into a pit made between two lateral eyes of 5 toe stage recipient tadpoles. Half of the operated tadpoles were treated with vitamin A (15 IU/ml.) for 15 days. Median "third eye" was found to develop in the both untreated and vitamin A treated tadpoles. However, vitamin A increased the percentage of the development of median eyes. Morphological and histological study revealed that newly transformed median eyes were similar to that of normal functional eyes. A stalk like structure developed which connects the median eye to the brain. The median third eye could not develop when pineal gland of 5 toe stage mature tadpole was transplanted into the tadpole of the same age.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bufonidae / growth & development*
  • Eye* / drug effects
  • Eye* / embryology
  • Larva / growth & development
  • Morphogenesis* / drug effects
  • Pineal Gland* / drug effects
  • Pineal Gland* / embryology
  • Vitamin A / pharmacology


  • Vitamin A