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5-HT3 receptor involvement in descending reflex relaxation in the rabbit isolated distal colon
- Source :
- European journal of pharmacology. 286(2)
- Publication Year :
- 1995
-
Abstract
- In whole segments of rabbit distal colon with mucosa removed, descending reflex relaxations of the circular muscle (descending inhibition) elicited by inflating (0.1-1 ml) an intraluminal balloon, were partially antagonized by 100 microM hexamethonium and the 5-HT3 receptor antagonist, ondansetron (3 microM), and abolished by 1 microM tetrodotoxin. The inhibitory effects of hexamethonium and ondansetron were additive. Conversely, hexamethonium (100 microM) and ondansetron (3 microM) failed to reduce electrically induced non-adrenergic non-cholinergic (NANC) relaxations of colonic circular muscle. It is concluded that interneuronally released acetylcholine and 5-hydroxytryptamine (5-HT) activate descending inhibitory pathways supplying the circular coat, via nicotinic and 5-HT3 receptors, respectively. This evidence suggests a functional involvement of 5-hydroxytryptaminergic transmission in the descending inhibition of rabbit colon.
- Subjects :
- Male
medicine.medical_specialty
medicine.drug_class
Colon
Biology
In Vitro Techniques
Hexamethonium
5-HT3 receptor
chemistry.chemical_compound
Internal medicine
Reflex
medicine
Animals
Receptor
5-HT receptor
Pharmacology
Receptor antagonist
Vasodilation
Endocrinology
chemistry
Receptors, Serotonin
Tetrodotoxin
biology.protein
Female
Rabbits
Serotonin Antagonists
Acetylcholine
medicine.drug
Subjects
Details
- ISSN :
- 00142999
- Volume :
- 286
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- European journal of pharmacology
- Accession number :
- edsair.doi.dedup.....53ab60a41dda7ab34da2788f9f715e6c