Otilonium is an inhibitor of L-type (IC
50 = 2.3 μM) and T-type calcium channels (IC
50s = 0.8, 1.1, and 0.4 μM for Ca
v3.1, Ca
v3.2, and Ca
v3.3, respectively).
1,2 It is also an antagonist of muscarinic acetylcholine receptors (mAChRs; IC
50s = 0.054, 0.4, 0.222, and 0.156 μM for M
1, M
2, M
4, and M
5 muscarinic receptors, respectively) and the platelet activating factor (PAF) receptor (IC
50 = 0.0552 μM).
3 Otilonium inhibits the inward calcium current in isolated rat colonic smooth muscle cells (EC
50 = 885 nM), an effect that can be blocked by the L-type calcium channel inhibitor nifedipine (Item No.
11106).
1 It inhibits contractions induced by the muscarinic acetylcholine receptor (mAChR) agonist methacholine in isolated circular muscle of the guinea pig proximal colon (IC
50 = 3.7 μM).
4 Otilonium (4 mg/kg) decreases fecal excretion and wet dog shakes and increases the tail withdrawal latency in the tail-flick test in a rat model of opioid withdrawal syndrome induced by morphine and naloxone.
5