Distribution of PACAP (pituitary adenylate cyclase-activating polypeptide)-like and helospectin-like peptides in the teleost gut.
Pituitary adenylate cyclase-activating polypeptide (PACAP) and helospectin are two vasoactive intestinal polypeptide (VIP)-related neuropeptides that have recently been demonstrated in the mammalian gut; the aim of this study was to reveal their occurrence and localisation in the gastrointestinal tract, swimbladder, urinary bladder and the vagal innervation of the gut of teleosts, using immunohistochemical methods on whole-mounts and sections of these tissues from the Atlantic cod, Gadus morhua and the rainbow trout, Oncorhynchus mykiss. Both PACAP-like and helospectin-like peptides were present in the gut wall of the two species. Immunoreactive nerve fibres were found in all layers but were most frequent in the myenteric plexus and along the circular muscle fibres. Immunoreactivity was also demonstrated in nerves innervating the swimbladder wall, the urinary bladder and blood vessels to the gut. Immunoreactive nerve cell bodies were found in the myenteric plexus of the gut and in the muscularis mucosae of the swimbladder. In the vagus nerve, non-immunoreactive nerve cells were surrounded by PACAP-immunoreactive fibres. Double staining revealed the coexistence of PACAP-like and helospectin-like peptides with VIP in all visualized nerve fibres and in some endocrine cells. It is concluded that PACAP-like and helospectin-like peptides coexist with VIP in nerves innervating the gut of two teleost species. The distribution suggests that both PACAP and helospectin, like VIP, are involved in the control of gut motility and secretion.
Department of Zoophysiology, University of Göteborg, Sweden.
C
C
Olsson
S
S
Holmgren
D000595:Amino Acid Sequence; D000818:Animals; D002316:Cardiotonic Agents / Q000032:analysis*; D004064:Digestive System / Q000737:chemistry* / Q000378:metabolism; D005399:Fishes / Q000378:metabolism*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000737:chemistry / Q000378:metabolism; D009197:Myenteric Plexus / Q000737:chemistry / Q000196:embryology; D009479:Neuropeptides / Q000032:analysis* / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010455:Peptides / Q000032:analysis* / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide / Q000032:analysis / Q000378:metabolism
D002316:Cardiotonic Agents; D036341:Intercellular Signaling Peptides and Proteins; D009479:Neuropeptides; D010455:Peptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; C043046:helospectin I; C043047:helospectin II