Differential effect on neuropeptide release of different concentrations of hydrogen ions on afferent and intrinsic neurons of the rat stomach
| Autor: | Pierangelo Geppetti, Elena Del Bianco, Carlo Alberto Maggi, Manuela Tramontana, B.M. Fusco, Stefano Evangelista, Daniela Renzi |
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| Rok vydání: | 1991 |
| Předmět: |
medicine.medical_specialty
Efferent Calcitonin Gene-Related Peptide Radioimmunoassay Neuropeptide Vasodilation In Vitro Techniques Substance P chemistry.chemical_compound In vivo Internal medicine medicine Animals Neurons Afferent Neurons Hepatology Stomach Gastroenterology Muscle Smooth Rats Inbred Strains Hydrogen-Ion Concentration In vitro Culture Media Rats Endocrinology medicine.anatomical_structure chemistry Capsaicin Calcitonin Gastric Mucosa Potassium Protons |
| Zdroj: | Gastroenterology. 101(6) |
| ISSN: | 0016-5085 |
| Popis: | In the muscle layer of the glandular portion of the rat stomach, in vivo capsaicin pretreatment markedly reduced calcitonin gene-related peptide—like immunoreactivity (CGRP-LI) but did not affect substance P—like immunoreactivity (SP-LI). Accordingly, in vitro superfusion of slices of this tissue with capsaicin (10 μmol/L) released CGRP-LI but not SP-LI, whereas both neuropeptides were released by 80 mmol/L K + . Exposure to relatively low-pH (pH 6) physiological salt solution induced an increase in the CGRP-LI outflow that was reduced by 70% in a Ca 2+ -free medium and was completely abolished by a previous exposure to capsaicin. However, superfusion with pH-6 medium did not produce any detectable SP-LI release. After exposure to pH-6 medium, both capsaicin and high-K + medium were still able to release a consistent quantity of CGRP-LI and SP-LI, respectively. Increased mucosal blood flow induced by acid back-diffusion is considered a protective mechanism against mucosal gastric lesion. The present findings suggest that hydrogen ions diffusing into the gastric wall may promote protective vasodilatation by activating the "efferent" function of capsaicin-sensitive nerves without affecting the secretory process of other intrinsic peptidergic neurons. |
| Databáze: | OpenAIRE |
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