Table 1.

Binding affinities for various α₁-adrenoceptor antagonists estimated at [³H]-silodosin and [³H]-prazosin-binding sites in rabbit prostate

Drug	[3H]-silodosin			[3H]-prazosin
	Segments		Membranes	Membranes
	pKi high (% high)	pKi low	pKi	pKi
Prazosin	8.8±0.1	7.1±0.2	9.9±0.2	9.8±0.2
	(42±4%)
Bunazosin	9.1±0.1	7.8±0.2
	(34±7%)
Silodosin	9.5±0.1		9.8±0.1	10.1±0.1
Tamsulosin	9.7±0.1
RS-17053	9.6±0.6	6.8±0.3
	(27±8%)
5-Methylurapidil	9.6±0.2	7.6±0.1	9.5±0.3	9.8±0.2
	(45±5%)
BMY-7378		5.2±0.2

Values from four or five experiments.

pK_i high and pK_i low: negative logarithm of equilibrium dissociation constants at high- and low-affinity sites for tested drugs.

% high: proportion of high-affinity sites.