Mechanism of Action
NK2 Receptor Selectivity
Kassinin has approximately 10-fold selectivity for NK2 receptors over NK1 receptors. NK2 is expressed in smooth muscle of the bronchi, gastrointestinal tract, and urinary tract. Gq-coupled NK2 activation causes bronchoconstriction and intestinal motility changes. This receptor preference made kassinin a key tool in establishing NK2 as a distinct receptor subtype.
Bronchomotor Effects
Kassinin constricts bronchial smooth muscle via NK2 activation, mimicking aspects of airway hyperresponsiveness seen in asthma. Studies using kassinin and NK2 antagonists helped establish the role of tachykinin signaling in bronchospasm, contributing to the development of NK2 antagonists for asthma therapy.
Research Summary
NK2 Receptor Pharmacology
PreclinicalKassinin served as a pivotal tool in the discovery of NK2 receptor selectivity. Comparative studies using kassinin, substance P, and other tachykinins across multiple tissue preparations revealed differential potency profiles that could not be explained by a single receptor class, leading to the NK1/NK2/NK3 classification.
GI Motility Research
PreclinicalIn gastrointestinal pharmacology, kassinin activates NK2 on intestinal smooth muscle to stimulate propulsive contractions. This has been used to model constipation-predominant bowel disorders and to evaluate NK2 antagonists as potential motility agents.
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Research Protocols
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| NK2 receptor binding | 1-1000 nM | Single | Binding assay |
| Bronchoconstriction model | 10-300 nM | Single | Isolated trachea preparation |
Research tool only. Not used therapeutically.
Interactions
Safety Profile
Kassinin causes bronchoconstriction and blood pressure changes through NK2 and NK1 activation. Not used therapeutically. Research applications are limited to in vitro pharmacology and animal models.
References
- [1]Anastasi A et al. (1977). Kassinin, a tachykinin dodecapeptide occurring in the skin of the African frog Kassina senegalensis. Identification and pharmacological properties. Experientia, 33(7), 857-858.
- [2]Maggi CA (1995). The mammalian tachykinin receptors. General Pharmacology, 26(5), 911-944.