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Pretreatment with clonidine caused desensitization to WIN 55,212-2 in guinea pig ileum.
- Source :
-
Autonomic & autacoid pharmacology [Auton Autacoid Pharmacol] 2014 Jan-Mar; Vol. 34 (1-2), pp. 9-13. - Publication Year :
- 2014
-
Abstract
- Considering the existence of cross-tolerance between clonidine and morphine besides the same interaction between morphine and WIN 55,212-2 persuaded us to verify this fact between WIN 55,212-2 and clonidine in guinea pig ileum, which is a well-known model to examine the mode of action of cannabinoids and α2 -adenoceptor agonists The rectangular pulses were passed to the 0.5 g stretched ileum segments that were fixed in 20-ml organ bath. PowerLab system and Graphpad Prism were applied to record twitches and analyse the data. Electrically evoked contractions were dose-dependently inhibited by WIN 55,212-2 and clonidine (pD2 = 8.56 ± 0.41 and 7.65 ± 0.15, respectively). Tolerance to this effect could be induced by 4-h incubation with WIN 55,212-2 (3 × IC50 ) (pD2  = 6.36 ± 0.26, degree of tolerance: 159.32) (P < 0.01) but not with clonidine (2 × IC50 and 4 × IC50 ) for different time courses. Dose-response curve for inhibitory action of WIN 55,212-2 was shifted to the right after 4-h incubation with clonidine (3 × 10(-10) m) comparing to the untreated tissues (pD2  = 5.26 ± 0.69, degree of tolerance: 2000) (P < 0.001). This observation provides the evidence for the cannabinoid-noradrenergic systems interaction in the enteric nervous system as a simplified representative for central nervous system.<br /> (© 2014 John Wiley & Sons Ltd.)
- Subjects :
- Animals
Dose-Response Relationship, Drug
Electric Stimulation
Enteric Nervous System physiology
Guinea Pigs
Ileum physiology
In Vitro Techniques
Male
Muscle Contraction drug effects
Muscle Contraction physiology
Benzoxazines antagonists & inhibitors
Benzoxazines pharmacology
Clonidine pharmacology
Drug Tolerance
Enteric Nervous System drug effects
Ileum drug effects
Morpholines antagonists & inhibitors
Morpholines pharmacology
Naphthalenes antagonists & inhibitors
Naphthalenes pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1474-8673
- Volume :
- 34
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- Autonomic & autacoid pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 24674577
- Full Text :
- https://doi.org/10.1111/aap.12018