Figure 6.

Effect of agonists specific to histamine receptor subtypes (H₁R, [A]; H₂R, [B]; H₃R, [C]; and H₄, [D]) on goblet cell glycoconjugate secretion. Cultured rat goblet cells were incubated with agonists specific to histamine receptor subtypes (10⁻⁷–10⁻⁴ M) for 2 hours. Glycoconjugate secretion was measured by enzyme-linked lectin assay. Data are mean ± SEM of four (4-methylhistamine) or five (histamine dimaleate, amthamine, and α-methylhistamine) independent experiments. * indicates statistical significance from no addition (0).