Calcitonin gene-related peptide: effect on contractile activity and luminal cross-sectional area in the isolated, perfused porcine ileum.
Because calcitonin gene-related peptide (CGRP) is an abundant peptide in the enteric nervous system we studied the effect of intra-arterial infusions of synthetic human CGRP I in concentrations from 10(-10) to 10(-8) mol/l on contractile activity and luminal cross-sectional area in the isolated perfused porcine ileum, using manometry and impedance planimetry. The frequency of the basal contractile activity was 0.37 +/- 0.1 contractions per minute. CGRP induced phasic contractions, which at the highest dose were superimposed on tonic contractions, as determined by measurement of luminal cross-sectional area. The frequency of contractions dose-dependently increased to approximately 10/min at 10(-8) mol/l CGRP. The amplitude of contractions increased from a maximum of 35 cm H2O to 51 +/- 3 at 5 x 10(-9) mol/l CGRP and 52 +/- 6 cm H2O at 10(-8) mol/l CGRP. After the termination of CGRP infusion at the highest dose a short phase of up to 5 min with strong tonic contraction was observed. No phasic activity was detected by manometry during this phase. In conclusion, CGRP dose-dependently increased contractile activity in the pig ileum. CGRP may therefore participate in the regulation of small-intestinal motility in the pig.
Rasmussen
T N
TN
Dept. of Medical Physiology C, Panum Institute, University of Copenhagen, Denmark.
Gregersen
H
H
Harling
H
H
Holst
J J
JJ
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005769:Gastrointestinal Motility / Q000187:drug effects; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008365:Manometry; D009119:Muscle Contraction / Q000187:drug effects*; D011312:Pressure; D013552:Swine
D015740:Calcitonin Gene-Related Peptide