Effects of cannabinoid receptor ligands on electrophysiological properties of myenteric neurones of the guinea-pig ileum
Article first published online: 5 FEB 2009
1997 British Pharmacological Society
British Journal of Pharmacology
Volume 122, Issue 2, pages 330–334, September 1997
How to Cite
López-Redondo, F., Lees, G. M. and Pertwee, R. G. (1997), Effects of cannabinoid receptor ligands on electrophysiological properties of myenteric neurones of the guinea-pig ileum. British Journal of Pharmacology, 122: 330–334. doi: 10.1038/sj.bjp.0701393
- Issue published online: 5 FEB 2009
- Article first published online: 5 FEB 2009
- (Received April 7, 1997, Revised June 16, 1997, Accepted June 20, 1997)
- Cannabinoid CB1 receptors;
- cholinergic neurotransmission;
- NANC neurotransmission;
- fast e.p.s.p.;
- slow e.p.s.p.;
- guinea-pig myenteric neurones
- 1The effect of cannabinoid receptor agonists was studied in guinea-pig myenteric neurones in vitro by use of conventional intracellular recording techniques.
- 2Exposure of myenteric neurones of the S-cell type to the cannabinoid receptor agonists WIN 55,212-2 (100 nM) and CP 55,940 (100 nM) reversibly and significantly depressed the amplitude of fast excitatory synaptic potentials (fast e.p.s.ps) by 46% and 37%, respectively.
- 3The depressant effect of WIN 55,212-2 and CP 55,940 on fast e.p.s.p. amplitude (expressed as the area above the amplitude-time curve (mVs)) was significantly greater than that of the vehicle, Tween 80, which had no detectable effect.
- 4The inhibitory effect of WIN 55,212-2 appeared to be concentration-dependent over the range 1–100 nM. WIN 55,212-3, its (−)-enantiomer (100 nM), was inactive.
- 5The cannabinoid CB1 receptor antagonist, SR141716A (1 μM), reversed the inhibitory effects of WIN 55,212-2 on fast e.p.s.ps in 38% of neurones tested (3/8) and acetylcholine (ACh)-induced depolarizations in 42% of neurones tested (5/12).
- 6When tested on its own, SR141716A (1 μM) caused a 40–50% reduction in the amplitude of fast e.p.s.ps (n=9).
- 7WIN 55,212-2 reversibly depressed the amplitude of the slow e.p.s.p. and, in 2 out of 7 neurones, this effect was reversed by SR141716A (1 μM).
- 8It is concluded that cannabinoid-induced inhibition of fast cholinergic synaptic transmission occurred by reversible activation of both presynaptic and postsynaptic CB1 receptors and that slow excitatory synaptic transmission can also be reversibly depressed by cannabinoids. Furthermore, it would seem that subpopulations of myenteric S-neurones and their synapsing cholinergic and non-cholinergic, non-adrenergic terminals are not endowed with cannabinoid receptors.
British Journal of Pharmacology (1997) 122, 330–334; doi:10.1038/sj.bjp.0701393