Postsmolt change in numbers of acetylcholinesterase-positive cells in the pineal organ of the Pacific coho salmon

Research output: Contribution to journalArticle


We have examined the occurrence of acetylcholinesterase (AChE)-positive cells in the pineal organ of different developmental stages of the Pacific coho salmon. Large numbers of AChE cells were present in fresh-water living alevins, in all stages of presmolts (n=307-544), and in adult spawners (n=696-1774) whereas seawater-living postmolts displayed a total lack of labeled cells. The AChE-reactive cells were evently distributed within the pineal end-vesicle and stalk of the presmolts and adults. However, the AChE-positive cells that occurred in the pineal stalk were of a smaller type and more uniform in shape than the cells of the pineal endvesicle. The dense populations of AChE-stained cells in the alevins, were all situated in the caudal part of the pineal end-vesicle. We conclude that changes in pineal metabolism occur in postsmolt salmon that liver in saltwater. It is not clear whether the observed change in pineal AChE expression is an "unspecific" change caused by life in the sea, reflecting alterations that are related to aspects of osmoregulation, and/or is involved in the visual function of the pineal organ resulting from changes in the environmental lighting conditions, e.g., photoperiod, light-intensity, or spectral composition. This study adds to our previous findings of changes that occur in the central nervous system of the salmon during the time of the parr-smolt transformation and migration between limnic and marine environments and indicates a possible central role of the pineal organ in the control of these events.


External organisations
  • University of Alaska Fairbanks
Research areas and keywords


  • Acetylcholinesterase, Central nervous system, Development, ontogenetic, Oncorhynchus kisutch (Teleostei), Parrsmolt transformation, Pineal organ
Original languageEnglish
Pages (from-to)281-286
Number of pages6
JournalCell & Tissue Research
Issue number2
Publication statusPublished - 1992 Nov 1
Publication categoryResearch