Table 2

Comparative functional antagonistic potencies of fiduxosin and standard α₁-adrenoceptor antagonists at α₁-adrenoceptors in isolated smooth muscle in vitro

Compound	Tissue and Receptor Subtype
Compound	Rat Vas Deferens α_1A	Canine Prostate α_1A	Rabbit Urethra α_1L	Rat Spleen α_1B	Rat Aorta α_1D
Fiduxosin^2-a
pA₂(±S.E.M.)	9.62 (±0.44)	8.51 (±0.23)	7.58 (±0.19)	7.08 (±0.07)	8.92 (±0.86)
Slope (±S.E.M.)	0.83 (±0.07)	0.80 (±0.05)	0.92 (±0.13)	0.90 (±0.05)	0.78 (±0.08)
[n]	[18]	[20]	[15]	[14]	[20]
Terazosin^2-b
pA₂(±S.E.M.)	8.04 (±0.45)	7.44 (±0.24)	6.77 (±0.30)	8.60 (±0.46)	8.65 (±0.29)
Slope (±S.E.M.)	0.83 (±0.17)	0.79 (±0.09)	0.99 (±0.07)	0.94 (±0.14)	0.99 (±0.13)
[n]	[12]	[35]	[13]	[12]	[9]
Tamsulosin^2-c
pA₂(±S.E.M.)	9.47 (±0.21)	9.54 (±0.17)	8.86 (±0.22)	9.69 (±0.44)	10.6 (±0.43)
Slope (±S.E.M.)	1.06 (±0.14)	1.12 (±0.08)	1.41 (±0.26)	0.84 (±0.15)	0.94 (±0.11)
[n]	[22]	[20]	[8]	[16]	[10]

Isolated smooth muscle strips or rings were incubated in tissue baths in the presence or absence of various concentrations of fiduxosin and standard α₁-adrenoceptor antagonists, as described underExperimental Procedures.

↵2-a One-way analysis of variance indicated the following potency order of statistically significant differences for fiduxosin: rat vas deferens > rat aorta ≅ canine prostate > rabbit urethra > rat spleen α₁-adrenoceptor antagonism.
↵2-b One-way analysis of variance indicated the following potency order of statistically significant differences for terazosin: rat aorta ≅ rat spleen > rat vas deferens > canine prostate > rabbit urethra α₁-adrenoceptor blockade.
↵2-c One-way analysis of variance indicated the following potency order of statistically significant differences for tamsulosin: rat aorta > canine prostate > rabbit urethra, but canine prostate ≅ rat vas deferens ≅ rat spleen and rat vas deferens ≅ rat spleen ≅ rabbit urethra α₁-adrenoceptor antagonism.