(N-[2-(2-CYCLOPROPYLMETHOXYPHENOXY)ETHYL]-5-CHLORO-ALPHA,ALPHA-DIMETHYL-1H-INDOLE-3-ETHANAMINE) HYDROCHLORIDE

pKi: 9.1 (α1 _A adrenoceptor in native cell membrane)
pA2: 9.8 (α1 _A adrenoceptor).

In several tissues from rat and cloned adrenoceptors, RS 17053 hydrochloride displays high affinity for the α1A-adrenoceptor (pK _i and pA ₂ estimates of 9.1-9.9) and a 30-100-fold selectivity over the α1 B and the α1 D-adrenoceptor subtypes (pK _i and pA ₂ estimates of 7.7-7.8). However, in isolated smooth muscle preparations from human LUT tissues, RS 17053 hydrochloride antagonizes responses to NE only at high concentrations. Estimates of affinity (pA ₂ ) at α1-adrenoceptors mediating NE-induced contractions are 7.5 in prostatic periurethral longitudinal smooth muscle (compared with 8.6 for prazosin), 6.9 in anterior fibromuscular stroma (prazosin, 8.9), and 7.1 in bladder neck (prazosin, 8.5).

RS 17053 hydrochloride has a rapid onset of action, and a duration of action exceeding 60 min. RS 17053 hydrochloride pretreatment significantly alteres food intake [F(4, 132) 5 6.28, p , 0.0001]. 10 mg/kg RS-17053 significantly suppresses food intake.