TABLE 3.

Responses to pharmacological agonists in precontracted coronary arteries and veins.

	Vein	Artery	Significance
Substance P
Tension at max. dose, relative to U46619 tension	0.95 ± 0.03, n = 13	0.05 ± 0.01, n = 15	p < 0.001
Acetylcholine
Tension at max. dose, relative to U46619 tension	0.39 ± 0.07, n = 12	3.31 ± 0.54, n = 12	p < 0.001
Noradrenaline
Tension at max. dose, relative to U46619 tension	1.39 ± 0.04, n = 12	0.06 ± 0.01, n = 12	p < 0.001

The responses to substance P, acetylcholine and noradrenaline in vessels precontracted with 10⁻⁷ M U46619 were determined. The tensions at maximal dose of the agonists are given relative to the U46619 induced tension. Three to four animals were used for arteries and veins, respectively. Statistical comparisons were made using Student’s t-test or Mann-Whitney rank sum test.