Effects of histamine on alpha adrenergic receptor expression on the lymphocytes of normal and asthmatic subjects.

Low levels of [3H]-dihydroergocryptine (DHE) (alpha adrenergic receptor) binding to peripheral blood mononuclear leukocytes from asthmatic subjects were significantly increased following incubation with histamine. In contrast, [3H]-DHE binding was undetectable both before and after histamine incubation using cells from nonasthmatic subjects. The change in binding showed a biphasic dose dependence on histamine and was not associated with changes in DHA (beta-2 receptor) or yohimbine (alpha-2 receptor) binding. The induction of alpha adrenergic receptors by the ubiquitous inflammatory mediator histamine may help explain the alpha adrenergic hyperresponsiveness seen in asthmatic patients.