Table 2

Agonist potency ratios of histamine receptors

HistamineH1 100H2 100H3 100
2-(3-(Trifluoromethyl)phenyl)histamine1282-a <0.12-a n.d.
2-(3-Bromophenyl)histamine1122-a <0.12-a n.d.
Nα-methylhistamine722-b 742-c 2702-d
2-(2-Thiazolyl)ethylamine262-b 2.22-b <0.0082-d
2-Methylhistamine172-c 42-c <0.082-d
2-(2-Pyridyl)ethylamine5.62-b 2.52-b n.d.
ArpromidineAntagonist2-e 10,2302-e
ImpromidineAntagonist2-f 4,8102-f Antagonist2-d , 2-o
Sopromidine22-g 7402-g Antagonist2-h , 2-p
Amthamine12-i 1502-i 0.0022-i
Dimaprit<0.00012-j 712-j Antagonist2-d , 2-q
4-Methylhistamine0.22-c 432-c <0.0082-d
Imetit<0.12-k 0.62-k 62002-k
Immepipn.d.n.d.24572-l
R-α-methylhistamine0.52-m 12-m 15502-m
S-α-methylhistamine0.52-b 1.72-b 132-m
R-α,S-β-dimethylhistamine0.072-n 0.12-n 18002-n
  • Values determined from guinea pig ileum contraction (H1), guinea pig atrium (chronotropic stimulation, H2), and inhibition of K+-stimulated histamine release from rat cerebral cortical slices (H3), or inhibition of electrically stimulated contraction of guinea pig ileum (H3). n.d., not determined.

  • 2-a Leschke et al. (1995)

  • 2-b Ganelin (1982)

  • 2-c Black et al. (1972)

  • 2-d Arang et al. (1983)

  • 2-e Sellier et al. (1992)

  • 2-f Durant et al. (1978)

  • 2-g Elz et al. (1989)

  • 2-h Arrang et al. (1985c)

  • 2-i Eriks et al. (1992)

  • 2-j Durant et al. (1977)

  • 2-k Garbarg et al. (1992)

  • 2-l Vollinga et al. (1994)

  • 2-m Arrang et al. (1987)

  • 2-n Lipp et al. (1992)

  • 2-o See table4.

  • 2-p KB = 56 nM.

  • 2-q KB = 3 μM.