P4.16 Role of M2 and M3 muscarinic receptor subtypes in mediating the cholinergic excitatory junction potentials in mouse ileum

Abstract

Functional roles of muscarinic acetylcholine receptors in generation of cholinergic excitatory junction potentials (EJPs) in the ileum were examined using mice genetically lacking muscarinic M2 and/or M3 receptors and their corresponding wild-type (WT) mice. Membrane potential responses were recorded in ileal longitudinal muscle strips using the conventional microelectrode technique, and EJPs were evoked by transmural electrical stimulation (TES: 0.5 ms duration, 30 V, five pulses at 20 Hz). When pertussis toxin (PTX) was pretreated, it was injected into mice at a dose of 100 μg/kg body weight (i.p.) and 70–74 h later, muscle strips were prepared from the mice.