Effects of anandamide on the binding and signaling properties of M1 muscarinic acetylcholine receptors
Section snippets
Materials
Drugs and chemicals were obtained from the following sources: [3H]NMS from NEN Life Science Products, (Boston, MA, USA), [3H]myo-inositol from Amersham Pharmacia Biotech (Buckinghamshire, UK), alcuronium chloride (generous gift from F. Hoffmann-La Roche Ltd., Basle, Switzerland), DMEM and geneticin were from Life Technologies GIBCO BRL (Grand Island, NY, USA), fetal bovine serum was from ThermoTrace, (Melbourne, VIC, Australia), and DOWEX AG1-X8 ion-exchange resin was obtained from Bio-Rad
Inhibition binding assays in CHO membranes
To examine the effects of anandamide on the binding of [3H]NMS to M1 CHO membranes, inhibition binding experiments were performed. Incubation of [3H]NMS and anandamide for 1 h revealed that the endocannabinoid was able to completely inhibit radioligand binding at the M1 mAChR, yielding a log IC50 of −5.55 ± 0.04 and nH of 2.23 ± 0.42 (n = 5; Fig. 2A). The steep Hill slope for anandamide was significantly different from unity (p < 0.05) and was not due to an equilibration artifact, since extending
Discussion
ACh and the endogenous cannabinoid, anandamide, exert profound, albeit opposing, regulatory effects on learning and memory. Although ACh mediates most of its effects through M1 mAChRs and anandamide through interaction with CB1 cannabinoid receptors, studies have recently demonstrated a direct effect of anandamide on antagonist binding to the mAChRs [21], [22]. The present study confirms and extends these previous findings, and suggests that anandamide may interact with the M1 mAChR through a
Acknowledgments
The authors are grateful to Dr. Fred Mitchelson for helpful discussions. This work was funded by Project Grant No. 209083 of the National Health and Medical Research Council (NHMRC) of Australia. Arthur Christopoulos is a senior research fellow of the NHMRC.
References (32)
- et al.
Role of cannabinoid receptors in memory storage
Neurobiol Dis
(1998) - et al.
Cannabinoids, hippocampal function and memory
Life Sci
(1999) - et al.
Muscarinic receptors involved in hippocampal plasticity
Life Sci
(1997) Muscarinic receptors-characterization, coupling and function
Pharmacol Ther
(1993)- et al.
Cannabinoid receptors and their ligands
Prostaglandins Leukot Essent Fatty Acids
(2002) - et al.
Effects of various psychotomimetic agents on the EEG and acetylcholine release from the cerebral cortex of brainstem transected cats
Neuropharmacology
(1972) - et al.
Anandamide receptors
Prostaglandins Leukot Essent Fatty Acids
(2002) - et al.
Endocannabinoids in the immune system and cancer
Prostaglandins Leukot Essent Fatty Acids
(2002) - et al.
Interaction of anandamide with the M1 and M4 muscarinic acetylcholine receptors
Brain Res
(2001) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein–dye binding
Anal Biochem
(1976)
Assessing the distribution of parameters in models of ligand–receptor interaction: to log or not to log
Trends Pharmacol Sci
Reduced high-affinity agonist binding at the M1 muscarinic receptor in Alzheimer's disease brain: differential sensitivity to agonists and divalent cations
Exp Neurol
Endogenous cannabinoid signaling
Neurobiol Dis
Cholinergic neurotransmission and synaptic plasticity concerning memory processing
Neurochem Res
Pharmacological drug treatment of Alzheimer disease: the cholinergic hypothesis revisited
J. Neuropathol Exp Neurol
International Union of PharmacologyXVII. Classification of muscarinic acetylcholine receptors
Pharmacol Rev
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Present address: Department of Pharmacology, Monash University, Clayton 3800, Australia.