Comparison of the presence and actions of substance P and neurokinin A in guinea-pig taenia coli
| Autor: | Roger Murphy, John B. Furness, C.W.R. Shuttleworth, S. Pompolo |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
medicine.medical_specialty Colon Neurokinin A Guinea Pigs Mepyramine Radioimmunoassay Substance P Guinea pig Cellular and Molecular Neuroscience chemistry.chemical_compound Endocrinology Internal medicine medicine Animals Chromatography High Pressure Liquid biology Endocrine and Autonomic Systems General Medicine respiratory system Taenia coli biology.organism_classification Denervation Immunohistochemistry medicine.anatomical_structure Neurology chemistry Tetrodotoxin Taenia Female medicine.drug |
| Zdroj: | Neuropeptides. 19:23-34 |
| ISSN: | 0143-4179 |
| DOI: | 10.1016/0143-4179(91)90070-y |
| Popis: | The presence and sites of action of two closely related tachykinins, substance P (SP) and neurokinin A (NKA), were examined in the taenia coli of the guinea-pig. SP- and NKA-like immunoreactivity (LI) were demonstrated histochemically in nerve fibres supplying the taenia. Chromatographic characterization of aqueous acetic acid extracts of taenia showed only one peak of SP-LI, corresponding in retention time to authentic SP, whereas there were multiple peaks of NKA-LI, the major one of which corresponded to authentic NKA. SP-LI and NKA-LI, determined by radioimmunoassay, were in a molar ratio of SP equivalents to NKA equivalents of 8.5:1 in taenia extracts. Extrinsic denervation of the caecum had no significant effect on the concentration of either SP-LI or NKA-LI or on their immunohistochemical distributions. Both SP and NKA (10 −10 to 10 −5 M) caused contractions of the taenia that were unaffected by hyoscine (10 −6 M), mepyramine (10 −6 M) or tetrodotoxin (5 × 10 −7 M), indicating that both peptides act directly on the smooth muscle of the taenia. Contractions to SP occurred after a short, but concentration-dependent, delay, reached a peak quickly, and then decayed. In contrast, NKA caused contractions after longer latencies, the peak was reached more slowly, and the response was maintained for up to 10 min. (D-Pro 2 , D-Trp 7,9 )-SP (10 −5 M) antagonised responses to SP and NKA to a similar degree. It is concluded that both NKA and SP should be considered as transmitter candidates for non-cholinergic nerve-mediated excitation in the taenia. |
| Databáze: | OpenAIRE |
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