Table 3.

Relaxation induced by P1 purinoceptor agonists

	n	pEC50	R (%)
Adenosine	10	4.3 ± 0.2	85.4 ± 8.8
NECA	8	7.5 ± 0.1*	99.1 ± 0.9
2-Cl-cyclopentyladenosine	6	5.2 ± 0.2*#	64.4 ± 11.8*#
CGS21680	8	6.4 ± 0.1*#Ω	100.0 ± 0.0Ω
2-Cl-IB-MECA	8	4.5 ± 0.1#ΩΨ	91.6 ± 5.5Ω

Results are expressed as mean ± SEM of n experiments.

^*#ΩΨP < 0.05 versus adenosine, NECA, 2-Cl-cyclopentyladenosine and CGS21680 respectively (analysis of variance followed by Bonferroni method).

2-Cl-cyclopentyladenosine, 2-chloro-N⁶-cyclopentyladenosine; 2-Cl-IB-MECA, 1-2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-b-D-ribofuranuronamide; CGS21680, 4-2[[6-amino-9-(N-ethyl-b-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzene propanoic acid hydrochloride; NECA, 5′-N-ethylcarboxamidoadenosine; pEC₅₀ = −log EC₅₀, where EC₅₀ is the concentration of agonist producing 50% relaxation of phenylephrine (PhE)-induced contraction; R is the relaxation, expressed as a percentage of the PhE-induced contraction, evoked at the highest concentration of agonist used: adenosine, 1 mM; NECA, 10 µM; 2-Cl-cyclopentyladenosine, 100 µM; CGS21680, 30 µM; and 2-Cl-IB-MECA, 100 µM.