Abstract
Purification and structural characterization of tachykinins from rainbow trout (Oncorhynchus mykiss) intestine has demonstrated the presence of three different peptides related to the mammalian tachykinins: substance P, neurokinin A, and neuropeptide-γ. The substance P- and the neurokinin A- related peptides present in the intestine are identical to the tachykinins previously isolated from the trout brain. The neuropeptide-γ-related peptide (Ser-Ser-Ala-Asn-Pro-Gln-Ile-Thr-Arg-Lys-Arg-His-Lys-Ile-Asn-Ser-Phe-Val- Gly-Leu-Met-NH2), not previously identified in brain tissue, has the sequence of the neurokinin A-related tachykinin at its COOH-terminus. Both trout substance P and neurokinin A stimulated the motility of isolated trout intestinal muscle [pD2 (-log of EC50) values 8.5 ± 0.15 and 7.35 ± 0.08, respectively] and the vascularly perfused trout stomach (pD2 values 9.63 ± 0.23 and 8.18 ± 0.23, respectively). Trout substance P was 14 times more potent than trout neurokinin A in the intestine and 28 times more potent in the stomach. The data suggest that receptors interacting with tachykinins in the trout gastrointestinal tract have a similar selectivity as the mammalian NK-1 receptor.
Original language | English |
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Pages (from-to) | R804-R810 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 265 |
Issue number | 4 34-4 |
DOIs | |
Publication status | Published (in print/issue) - 1993 |
Keywords
- fish
- gastrointestinal motility
- neurokinin A
- neuropeptide-γ
- substance P