Neuropeptides in the Australian lungfish Neoceratodus forsteri: Effects in vivo and presence in autonomic nerves

S. Holmgren, R. Fritsche, P. Karila, I. Gibbins, M. Axelsson, C. Franklin, G. Grigg, S. Nilsson

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The Australian lungfish Neoceratodus forsteri is one of the few extant species of a phylogenetically ancient group. Immunohistochemistry showed the presence of galanin-, vasoactive intestinal polypeptide (VIP)-, neurotensin- , substance P-, and calcitonin gene-related peptide (CGRP)-like immunoreactivities in nerve fibers in the heart, lung, and gut, with a coexistence of VIP-, galanin-, and somatostatin-like immunoreactivity in the lung and galanin- and somatostatin-like immunoreactivity in the gut. About 20% of the substance P-immunoreactive fibers in gut and lung contained CGRP- like material. Major vessels showed a sparse innervation. In free-swimming unanesthetized fish, neurotensin (1 nmol/kg), galanin (1 nmol/kg), and bombesin (10 nmol/kg) reduced the heart rate. In two specimens tested, the effect of neurotensin was partially antagonized by atropine. Galanin and bombesin reduced and cholecystokinin 8 (CCK-8-S) increased blood flow to the lung. Neurotensin decreased, CCK-8-S increased, and substance P had no effect on dorsal aortic pressure, and all three decreased flow to the gut. It can be concluded from the present study that the general vertebrate pattern of cardiovascular and visceral nervous control by several neuropeptides is present also in Neoceratodus.

Original languageEnglish
Pages (from-to)R1568-R1577
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume266
Issue number5 35-5
DOIs
Publication statusPublished - May 1994
Externally publishedYes

Keywords

  • blood flow
  • bombesin
  • calcitonin gene- related peptide
  • cholecystokinin
  • Dipnoan
  • galanin
  • neurotensin
  • nonmammalian vertebrate
  • somatostatin
  • substance P
  • vasoactive intestinal polypeptide

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