Vasoactive intestinal polypeptide immunoreactive nerves in the gill arch of teleost fish, Carassius auratus L

The localization of vasoactive intestinal polypeptide (VIP)-immunoreactive (ir) nerve cell bodies and fibers has been studied in the gill arches of goldfish (Carassius auratus, L.) using the peroxidase-antiperoxidase (PAP) immunohistochemical method. It was found that VIP-ir nerve cell bodies are localized in connective tissue on the oral side of the gill arch; these cells were present as single cells, in couples or as small clusters. Moreover, a dense network of VIP-ir fibers was observed beneath the lining epithelium of the raker cushion. The possible involvement of this peptide in mucus secretion in the gill arches of teleost is discussed.