Table 1.

(A) Dopamine receptor agonists. The main dopamine receptors on which the commonly used dopamine receptor agonist acts are listed here in five columns. Dopamine is an agonist at all dopamine receptors, albeit with varying affinities. One would predict in the heart that first high-affinity dopamine receptors, and thereafter, low-affinity receptors, will be stimulated by dopamine. Note that there is no drug currently available that allows for distinguishing between D₁-dopamine and D₅-dopamine receptors. Usually, antagonists do not distinguish between D₂-, D₃-, D₄-dopamine receptors. Moreover, at higher concentrations, for instance, fluphenazine antagonizes also at the D₁-dopamine receptors. Moreover, antagonists usually are not dopamine receptor-selective. For instance, metoclopramide also acts antagonistically on cardiac 5-HT₄-serotonin receptors and domperidon on cardiac potassium channels. (B) Dopamine receptor antagonists. The main dopamine receptors on which commonly used dopamine receptor antagonists act are listed here in five columns. Note that there is no antagonist that is currently available that allows to distinguish between D₁-dopamine and D₅-dopamine receptors. Usually, antagonists do not distinguish between D₂-, D₃-, D₄-dopamine receptors. Moreover, at higher concentrations, for instance, fluphenazine antagonizes also at D₁-dopamine receptors. Moreover, antagonists usually are not dopamine receptor-selective. For instance, metoclopramide also acts antagonistically on cardiac 5-HT₄-serotonin receptors, and domperidon acts antagonistically on cardiac potassium channels. Superscript numbers indicate which drug was used in which reference. Ki indicates the half maximum concentration to inhibit a function and pKi represents its negative decadic logarithm.

(A) Dopamine Receptor Agonists
D1	D2	D3	D4	D5	Reference
dopamine pKi: 4.3–5.6	dopamine pKi: 4.3–5.6	dopamine pKi: 6.3–7.4	dopamine pKi: 7.6	dopamine pKi: 6.6	Myslivecek 2022 [1]
1 SKF-38393	2 MLS1547			1 SKF-38393	1 Ding et al. 2008 [2] 2 Myslivecek 2022 [1]
AT77636	rotigotine	rotigotine	rotigotine	AT77636	Myslivecek 2022 [1]
1SKF-81297	1 ropinirole	1 ropinirole	2 quinpirole	1 SKF-81297	1 Myslivecek 2022 [1] 2 Yamaguchi et al., 1997 [3]
1 SKF-83959	1,2 pramipexol	1,2 pramipexol	2 pramipexol	1 SKF-83959	1 Myslivecek 2022 [1] 2 Piercey et al., 1996 [4]
fenoldopam (=SKF 82526)	2 PD 128907	PD 128907		fenoldopam (=SKF 82526)	Myslivecek 2022 [1]
2A68930	1 PD16077		1PD16077		1 Myslivecek 2022 [1] 2 DeNinno et al., 1990 [5]
2 chloro APB	1 A412997	1A412997	1 A412997		1 Myslivecek 2022 [1] 2 Neumeyer et al., 1991 [6]
dihydrexidine					Salmi et al., 2004 [7]
	apomorphine				Myslivecek 2022 [1]
	propylbutyl-dopamine				Zhao et al. 1990 [8]
	SKF81297				Rashid et al., 2007 [9]
	quinpirole				Rashid et al., 2007 [9]
bromocriptine 0.1 µM (as Ki)	bromocriptine				Kvernmo et al., 2008 [10]
pergolide 0.6 µM (as Ki)	pergolide				Kvernmo et al., 2008 [10]
(B) Dopamine Receptor Antagonists
D1	D2	D3	D4	D5	Reference
2 haloperidol	2 haloperidol	2 S33084	2 L745870		2 Myslivecek 2022 [1]
1 SCH-38390	2 pipotiazine	2 SB277011-A	2 sonepiprazole	1 SCH-39390	1 Ding et al. 2008 [2]
2,3 SKF-83566	2 perospirone	2 perospirone	2 perospirone	2 SKF-83566	2 Myslivecek 2022 [1] 3 Kopia and Valocik 1989 [11]
2 ecopipam	2 raclopride	2 raclopride	2 A-381393	2 ecopipam	2 Myslivecek 2022 [1]
2 SCH23982	2 ML321	2 sulpiride	2 sulpiride		2 Myslivecek 2022 [1]
1 odapipam (=NNC 756 Ki: 0.17 nM)	1 odapipam (Ki: 942 nM) 2 prochlorperazine	2 prochlorperazine	2 prochlorper-azine		1 Andersen et al., 1992 [12] 2 Myslivecek 2022 [1]
	NGB 2904	NGB 2904	NGB 2904		Myslivecek 2022 [1]
	metoclopramide	S14297	S14297		Myslivecek 2022 [1]
	domperidon				Myslivecek 2022 [1]
	pimozide	pimozide	pimozide		Lumley et al., 1977 [13]
fluphenazine	fluphenazine				Vettel et al., 2014 [14]
	melperone				Lencesova et al., 2017 [15]
cabergoline	cabergoline				Myslivecek 2022 [1]

Pergolide and bromocriptine have an affinity of 0.1 µM (as Ki) or 0.6 µM at D₁-dopamine receptors; therefore, they can act as agonists at D₁-dopamine receptors.