The pineal complex of the three-spined stickleback, Gasterosteus aculeatus L. - A light-, electron microscopic and fluorescence histochemical investigation

Research output: Contribution to journalArticle


The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.


External organisations
  • University of Copenhagen
  • Lund University
Research areas and keywords


  • Electron microscopy, Epiphysis cerebri, Fluorescence histochemistry, Gasterosteus aculeatus L, Parapineal organ, Teleostei
Original languageEnglish
Pages (from-to)11-28
Number of pages18
JournalCell and Tissue Research
Issue number1
Publication statusPublished - 1980 Jul 1
Publication categoryResearch