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Differential effects of anandamide on acetylcholine release in the guinea‐pig ileum mediated via vanilloid and non‐CB 1 cannabinoid receptors

Differential effects of anandamide on acetylcholine release in the guinea‐pig ileum mediated via... The effects of anandamide on (3H)‐acetylcholine release and muscle contraction were studied on the myenteric plexus‐longitudinal muscle preparation of the guinea‐pig ileum preincubated with (3H)‐choline. Anandamide increased both basal (3H)‐acetylcholine release (pEC50 6.3) and muscle tone (pEC50 6.3). The concentration‐response curves for anandamide were shifted to the right by 1 μM capsazepine (pKB 7.5 and 7.6), and by the combined blockade of NK1 and NK3 tachykinin receptors with the antagonists CP99994 plus SR142801 (each 0.1 μM). The CB1 and CB2 receptor antagonists, SR141716A (1 μM) and SR144528 (30 nM), did not modify the facilitatory effects of anandamide. Anandamide inhibited the electrically‐evoked release of (3H)‐acetylcholine (pEC50 5.8) and contractions (pEC50 5.2). The contractile response to the muscarinic agonist methacholine was not significantly affected by 10 μM anandamide. The inhibitory effects of anandamide were not changed by either capsazepine (1 μM), SR144528 (30 nM) or CP99994 plus SR142801 (each 0.1 μM). SR141716A (1 μM) produced rightward shifts in the inhibitory concentration‐response curves for anandamide yielding pKB values of 6.6 and 6.2. CP55940 inhibited the evoked (3H)‐acetylcholine release and contractions, and SR141716A (0.1 μM) shifted the concentration‐response curves of CP55940 to the right with pKB values of 8.4 and 8.9. The experiments confirm the existence of release‐inhibitory CB1 receptors on cholinergic myenteric neurones. We conclude that anandamide inhibits the evoked acetylcholine release via stimulation of a receptor that is different from the CB1 and CB2 receptor. Furthermore, anandamide increases basal acetylcholine release via stimulation of vanilloid receptors located at primary afferent fibres. British Journal of Pharmacology (2001) 134, 161–167; doi:10.1038/sj.bjp.0704220 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png British Journal of Pharmacology Wiley

Differential effects of anandamide on acetylcholine release in the guinea‐pig ileum mediated via vanilloid and non‐CB 1 cannabinoid receptors

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References (24)

Publisher
Wiley
Copyright
2001 British Pharmacological Society
ISSN
0007-1188
eISSN
1476-5381
DOI
10.1038/sj.bjp.0704220
pmid
11522608
Publisher site
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Abstract

The effects of anandamide on (3H)‐acetylcholine release and muscle contraction were studied on the myenteric plexus‐longitudinal muscle preparation of the guinea‐pig ileum preincubated with (3H)‐choline. Anandamide increased both basal (3H)‐acetylcholine release (pEC50 6.3) and muscle tone (pEC50 6.3). The concentration‐response curves for anandamide were shifted to the right by 1 μM capsazepine (pKB 7.5 and 7.6), and by the combined blockade of NK1 and NK3 tachykinin receptors with the antagonists CP99994 plus SR142801 (each 0.1 μM). The CB1 and CB2 receptor antagonists, SR141716A (1 μM) and SR144528 (30 nM), did not modify the facilitatory effects of anandamide. Anandamide inhibited the electrically‐evoked release of (3H)‐acetylcholine (pEC50 5.8) and contractions (pEC50 5.2). The contractile response to the muscarinic agonist methacholine was not significantly affected by 10 μM anandamide. The inhibitory effects of anandamide were not changed by either capsazepine (1 μM), SR144528 (30 nM) or CP99994 plus SR142801 (each 0.1 μM). SR141716A (1 μM) produced rightward shifts in the inhibitory concentration‐response curves for anandamide yielding pKB values of 6.6 and 6.2. CP55940 inhibited the evoked (3H)‐acetylcholine release and contractions, and SR141716A (0.1 μM) shifted the concentration‐response curves of CP55940 to the right with pKB values of 8.4 and 8.9. The experiments confirm the existence of release‐inhibitory CB1 receptors on cholinergic myenteric neurones. We conclude that anandamide inhibits the evoked acetylcholine release via stimulation of a receptor that is different from the CB1 and CB2 receptor. Furthermore, anandamide increases basal acetylcholine release via stimulation of vanilloid receptors located at primary afferent fibres. British Journal of Pharmacology (2001) 134, 161–167; doi:10.1038/sj.bjp.0704220

Journal

British Journal of Pharmacology – Wiley

Published: Sep 1, 2001

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