Table 4: IC50 Values (μM) of 30 Known Cholinergic Antagonists Determined in the IP-One and Intracellular Calcium Assays in M1-CHO Cells

Compound Property Calcium Assay IP-One Assay
Tropicamide MAR anta. (M4) 2.00 3.16
Atropine methyl bromide MAR anta. 0.01 0.003
Atropine sulfate MAR anta. 0.01 0.001
Atropine methyl nitrate MAR anta. 0.013 0.001
BW 284c51 Ach. Inh. 6.31 12.6
Aminobenztropine MAR anta. 0.016 0.003
Benztropine mesylate MAR anta. 0.008 0.013
4-DAMP methiodide M3 and M5 MAR anta. 0.016 0.006
Dicyclomine hydrochloride MAR anta. 0.039 0.631
4-DAMP mustard hydrochloride Irreversible MAR anta. 0.10 0.126
L-Hyoscyamine MAR anta. 0.01 0.501
Ipratropium bromide MAR anta. 0.016 0.004
DL-Homatropine hydrobromide MAR anta. 0.16 0.001
Hexahydro-sila-difenidol hydrochloride, p-fluoro analog MAR anta. 0.16 1.58
MG 624 NAR anta. 0.13 0.398
Methoctramine tetrahydrochloride MAR anta.(M2 selective) 1.00 3.98
Orphenadrine hydrochloride MAR anta. 0.50 1.00
Pancuronium bromide skeletal muscle relaxant 10.0 12.6
Oxybutynin Chloride MAR anta. 0.025 0.039
Pirenzepine dihydrochloride MAR anta. 0.10 0.126
Propantheline bromide MAR anta. 0.012 0.001
(-)-Scopolamine hydrobromide MAR anta. 0.012 0.004
(-)-Scopolamine methyl nitrate MAR anta. 0.012 0.001
(-)-Scopolamine,n-Butyl-, bromide MAR anta. 0.16 0.50
(-)-Scopolamine methyl bromide MAR anta. 0.013 0.001
Trihexyphenidyl hydrochloride MAR anta. 0.025 0.0251
N,N,N-trimethyl-1-(4-trans-stilbenoxy)-2-propylammonium NAR anta. 3.98 7.94
Telenzepine dihydrochloride MAR anta. (M1 select) 0.032 0.025
WB 64 MAR anta. 0.398 0.398
9-Amino-1,2,3,4-tetrahydroacridine Ach inh. 15.8 10.0

Note: MAR - muscarinic acetylcholine receptor; anta. – antagonist; Ach. Inh. – acetylcholinesterase inhibitor; NAR - Nicotinic acetylcholine receptor.