Histamine-induced cutaneous wheal responses were measured in 24 healthy subjects. The effect of the potent H, blocker, hydroxyaine HCL the % blocker, cimetidine, and the two drugs in combination was detern¢¥iined. The H, blocker alone produced a mean wheal suppression of 770/o(p(0.005). The % blocker alone produced a mean wheal suppression of 35%(p <0.01). The Hi plus q blocker produced 79% suppression. But the augmented suppression of H,-plus HZ blocker vs H, blocker was not statistically significant (p > 0.05). The result pro-vide evidence that % receptors are present in the human cutaneous blood vessel, but additional studies must be performed to determine the significance of combined Hi and % blockade over H, blocker alone in suppression of histamine-induced wheal formation.
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