Pharmacological characterization of a rat 5-hydroxytryptamine type_3 receptor subunit (r5-HT_3A(b)) expressed in Xenopus laevis oocytes

摘要

The present study has utilized the two electrode voltage-clamp technique to examine the pharmacological profile of a splice variant of the rat orthologue of the 5-hydroxytryptamine type 3A subunit (5-HT_3A(b)) heterologously expressed in Xenopus laevis oocytes. At negative holding potentials, bath applied 5-HT (300 nM-10μM) evoked a transient, Concentration-dependent (EC_50=1.1±0.1 μM), inward current. The response reversed in sign at a Holding potential of -2.1±1.6 mV. The response to 5-HT was mimicked by the 5-HT_3 receptor selective agonists 2-methyl-5-HT (EC_50 =4.1±0.2μM), 1-phenylbiguanide(EC_50 = 3.0±0.4μM), 3-chlorophenylibiguanide (EC_50 = 140± 10 nM), 3,5-dichlorophenylbiguanide(EC_50 = 14.5±0.4nM) and 2,5-dichlorophenylbiguanide(EC_50 = 10.2±0.6 mM).