Histamine H1-receptors in the guinea-pig urinary bladder.
Histamine H1-receptors were identified in the guinea-pig urinary bladder. Histamine (10(-8)-10(-3) M) produced a dose-dependent contraction which was not altered by either scopolamine or tetrodotoxin. Specific [3H]mepyramine binding to the urinary bladder was saturable and there was a single population of high affinity binding sites with an equilibrium dissociation constant (KD) of 0.77 nM and maximum binding capacity (Bmax) of 68.5 fmol/mg protein. Histamine-induced contraction and [3H]mepyramine binding were inhibited by triploridine, promethazine, d-chlorpheniramine and mepyramine but not by cimetidine. There was a good correlation between mechanical activity and [3H]mepyramine binding as shown by the inhibition affinity constant (Ki) of H1-antagonists. These results provide evidence that the histamine H1-receptor in the guinea-pig urinary bladder is involved in the histamine-induced contraction.
Kondo
M
M
Taniyama
K
K
Tanaka
C
C
D000818:Animals; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000378:metabolism; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D011738:Pyrilamine / Q000378:metabolism; D011968:Receptors, Histamine / Q000378:metabolism*; D011969:Receptors, Histamine H1 / Q000378:metabolism*; D001743:Urinary Bladder / Q000294:innervation / Q000378:metabolism*
D006634:Histamine H1 Antagonists; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D006632:Histamine; D011738:Pyrilamine