Table 5 Antagonistic potency of K18 at A3R mutants.

From: Pharmacological characterisation of novel adenosine A3 receptor antagonists

 

pIC50a

Eminb

Basalc

True basald

Spane

n

+ DMSO

WT

10.73 ± 0.1

35.0 ± 1.6

60.1 ± 0.9

57.7 ± 1.3

25.1 ± 2.0

11

L90A

9.03 ± 0.1****

43.3 ± 3.2

73.2 ± 2.7***

71.5 ± 2.9***

29.9 ± 1.8

8

V169A

11.33 ± 0.1****

30.9 ± 1.7

55.3 ± 2.4

54.1 ± 2.5

24.3 ± 2.1

10

M177A

7.65 ± 0.1****

38.6 ± 2.7

70.2 ± 2.0*

66.7 ± 1.8

31.6 ± 2.0

7

I249A

10.76 ± 0.1

34.9 ± 2.2

62.6 ± 2.7

59.9 ± 2.6

27.7 ± 1.3

11

L264A

10.53 ± 0.1

41.1 ± 2.2

72.0 ± 2.3**

70.8 ± 2.6**

30.9 ± 2.2

9

+ 0.1 μM K18

WT

10.64 ± 0.1

37.3 ± 1.8

63.0 ± 2.2

61.8 ± 2.6

25.8 ± 0.9

5

L90A

7.88 ± 0.1****

50.2 ± 3.4*

77.2 ± 2.6**

74.9 ± 2.8*

27.0 ± 3.1

7

V169A

11.11 ± 0.1 *

31.9 ± 1.8

62.6 ± 2.2

60.6 ± 3.1

30.6 ± 2.1

7

M177A

7.69 ± 0.1****

38.8 ± 2.5

70.9 ± 2.4

68.7 ± 2.3

32.1 ± 1.9

5

I249A

10.65 ± 0.1

35.6 ± 3.1

68.5 ± 3.3

67.0 ± 3.4

32.9 ± 1.3

8

L264A

9.86 ± 0.1***

45.7 ± 2.0

79.7 ± 2.7**

77.7 ± 3.0**

34.0 ± 2.8

7

+ 1 μM K18

WT

9.65 ± 0.1

38.3 ± 2.4

67.4 ± 1.5

63.0 ± 1.8

29.1 ± 2.0

6

L90A

6.61 ± 0.1****

54.3 ± 3.6**

76.7 ± 3.2

73.5 ± 3.1

22.4 ± 2.6

8

V169A

10.40 ± 0.1****

31.9 ± 2.3

68.8 ± 1.7

66.5 ± 2.0

36.9 ± 2.5

7

M177A

7.27 ± 0.1****

40.0 ± 3.5

71.4 ± 2.4

66.3 ± 2.5

31.4 ± 2.0

5

I249A

9.78 ± 0.1

36.9 ± 3.2

76.3 ± 3.7

73.1 ± 3.8

39.3 ± 2.1*

8

L264A

8.80 ± 0.1****

47.9 ± 2.7

83.6 ± 2.1***

79.8 ± 2.4**

35.7 ± 3.0

8

+ 10 μM K18

WT

8.38 ± 0.2

45.1 ± 1.7

72.0 ± 1.5

68.9 ± 1.6

26.9 ± 1.3

7

L90A

ND

59.9 ± 2.9**

81.7 ± 2.3

78.1 ± 2.4

22.8 ± 2.0

5

V169A

9.44 ± 0.1****

33.5 ± 1.8**

71.8 ± 1.6

69.2 ± 1.5

38.3 ± 2.0*

8

M177A

6.12 ± 0.2****

45.7 ± 3.2

72.1 ± 2.3

67.6 ± 2.4

26.6 ± 1.6

5

I249A

8.55 ± 0.2

36.6 ± 2.1*

78.0 ± 4.2

74.7 ± 4.2

38.7 ± 3.6*

8

L264A

7.98 ± 0.1

49.1 ± 3.1

85.4 ± 2.7*

82.8 ± 2.6**

33.7 ± 5.0

5

  1. cAMP accumulation as measured in Flp-In-CHO cells stably expressing WT or mutant A3R following stimulation with 10 μM forskolin, varying concentrations of IB-MECA and ±K18 at the indicated concentration.
  2. Data are expressed as mean ± SEM obtained in n separate experiments. All individual experiments were conducted in duplicate.
  3. ND indicates an incomplete dose response curve due to the increased potency of K18 at this mutant.
  4. aNegative logarithm of IB-MECA concentration required to produce a half-maximal response.
  5. bMinimum cAMP accumulation of IB-MECA as %100 μM forskolin. The lower plateau of the fitted sigmoidal dose response curve.
  6. cThe upper plateau of the fitted sigmoidal dose response curve corresponding %100 μM forskolin.
  7. dThe cAMP accumulation when stimulated with 10 μM forskolin only + DMSO/K18 at the indicated concentration.
  8. eThe difference between Emin and basal signalling.
  9. Statistical significance (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001) compared to WT IB-MECA stimulation ± K18 at each indicated concentration was determined by one-way ANOVA with Dunnett’s post-test.
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