Background:

Homatropine methylbromide (Homatropine methobromide) is muscarinic AChR antagonist, inhibits endothelial and smooth muscle muscarinic receptors of WKY-E and SHR-E with IC50 of 162.5 nM and 170.3 nM, respectively.

Homatropine methylbromide (Homatropine methobromide) (20 μM) alone produces a dose ratio of 259 in atrium from guinea-pigs. Homatropine methylbromide (Homatropine methobromide) (20 μM) produces a dose ratio of only 95.0 when combined with hexamethonium in atrium from guinea-pigs.

Pre-treatment with Homatropine methylbromide (Homatropine methobromide) (20 mg/kg) was comparable with atropine (10 mg/kg) in preventing lethality in this rat model of acute OC poisoning.

参考文献:
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[2]. Bryant SM et al. Intramuscular ophthalmic homatropine vs. atropine to prevent lethality in rates with dichlorvos poisoning. J Med Toxicol. 2006 Dec;2(4):156-9.
[3]. Leung E et al. Modification by hexamethonium of the muscarinic receptors blocking activity of pancuronium and homatropine in isolated tissues of the guinea-pig.Eur J Pharmacol. 1982 May 7;80(1):11-7.