Histamine H2-binding on guinea pig cerebral cortex.
The Kd-values of some histamine H2-active compounds, obtained from radio-ligand-binding studies on a homogenate of the guinea-pig cerebral cortex with 3H-tiotidine as the labelled H2-ligand, were compared with the pA2/pD2-value of these compounds on the guinea-pig right atrium and guinea-pig isolated gastric fundus. A good correlation was found between the pKd of the H2-antagonists and their pA2 on the guinea-pig right atrium. A much poorer correlation however was obtained between the pKd of the agonists on the cerebral cortex and their pD2-values on the guinea-pig right atrium and the gastric fundus. This poor correlation between true affinity and H2-activity of the agonists might be explained by spare receptors as a much better correlation was obtained between pKd and pD2 of partial agonists.
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D002927:Cimetidine / Q000031:analogs & derivatives / Q000378:metabolism; D005744:Gastric Acid / Q000378:metabolism; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism; D011968:Receptors, Histamine / Q000378:metabolism*; D011970:Receptors, Histamine H2 / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D014316:Tritium
D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D014316:Tritium; D002927:Cimetidine; D006632:Histamine; C023990:tiotidine