Role of Opioid Peptides in Behavior of Invertebrates

  • V. E. Dyakonova

DOI: 10.1023/A:1012910525424

Cite this article as:
Dyakonova, V.E. Journal of Evolutionary Biochemistry and Physiology (2001) 37: 335. doi:10.1023/A:1012910525424


Opioid peptides have been revealed in representatives of practically all large taxonomic groups of invertebrates, and the opiate receptors are found even in unicellulars. The opioid system seems to belong to the evolutionary ancient signal systems. The comparative data indicate that the most conservative and ancient function of opioids is control of the adequate level of protective reactions. In the infusorian Stentor the opiate ligands suppress a contractile response to mechanical stimulation, i.e., the protective behavior. In all studies multicellular invertebrates, agonists also suppress protective behavior, whereas antagonists produce opposite effects. This initially signal meaning of opioids might have become a basis for divergent development of their functions in evolution. Already in higher invertebrates, molluscs and arthropods, many functions of opioids, for example, stress-induced analgesia, regulation of feeding and mating behavior, of social aggression, are similar to those in vertebrates. It is suggested that the main events in formation of functions of the endogenous opioid system have occurred in the lower invertebrates that have remained so far the least studied.

Copyright information

© MAIK “Nauka/Interperiodica” 2001

Authors and Affiliations

  • V. E. Dyakonova
    • 1
  1. 1.Russian Academy of SciencesKol'tsov Institute of Biology of DevelopmentMoscowRussia

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