Substance P and CGRP mediate motor response of rabbit colon to capsaicin
| Autor: | W. J. Snape, A. Kodner, H. S. Ennes, C. B. M. Koelbel, V. E. Eysselein, Emeran A. Mayer |
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| Rok vydání: | 1990 |
| Předmět: |
Atropine
Male medicine.medical_specialty Colon Physiology Calcitonin Gene-Related Peptide Stimulation Substance P Hexamethonium Compounds Tetrodotoxin Bethanechol In Vitro Techniques Biology Calcitonin gene-related peptide Hexamethonium chemistry.chemical_compound Adenosine Triphosphate Physiology (medical) Internal medicine medicine Animals Myenteric plexus Neurons Afferent Pathways Hepatology Gastroenterology Muscle Smooth Acetylcholine Kinetics medicine.anatomical_structure Endocrinology chemistry Peripheral nervous system Rabbits Capsaicin medicine.symptom Gastrointestinal Motility medicine.drug Muscle contraction |
| Zdroj: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 259:G889-G897 |
| ISSN: | 1522-1547 0193-1857 |
| DOI: | 10.1152/ajpgi.1990.259.5.g889 |
| Popis: | Primary afferent nerve terminals located in the mammalian gut wall may play a role in region-specific modulation of gastrointestinal motility. In the present study, we sought to characterize the effect of neuropeptides released from these afferents by capsaicin (CAP) on contractile activity of smooth muscle from the distal rabbit colon. CAP caused a release of acetylcholine and immunoreactivity for substance P (SP) and calcitonin gene-related peptide (CGRP) from the muscle coat. CAP caused a dose-dependent transient stimulation of longitudinal muscle contractions, followed by prolonged inhibition of spontaneous but not stimulated contractile activity. The initial stimulation was abolished by the SP antagonist spantide and by atropine. The inhibitory effect was reduced by repeated exposure of muscle to CGRP. The effect of CGRP on spontaneous contractions differed between longitudinal and circular muscle. In longitudinal muscle, a stimulation was preceded by a transient inhibition, whereas in circular muscle, only inhibition was seen. Both effects were resistant to tetrodotoxin. Repeated exposure of circular but not longitudinal muscle to CGRP resulted in a disappearance of the peptide's inhibitory effect. Exogenously applied CGRP was only a weak antagonist of contractions stimulated by SP and bethanechol. These findings suggest that in the rabbit colon at least the following two neuropeptides are released from CAP-sensitive nerve fibers: a neurokinin peptide from nerve terminals located within the myenteric plexus and CGRP from terminals probably located within the circular muscle layer. |
| Databáze: | OpenAIRE |
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