Effects of Ketotifen on the Responsiveness of Peripheral Blood Lymphocyte β-Adrenergic Receptors

Document Type

Article

Publication Date

1-1-1988

Description

The effects of ketotifen therapy on the responsiveness of lymphocyte β-adrenergic receptors was evaluated by measuring cyclic AMP elevations caused by isoproterenol in cells isolated from patients treated with ketotifen for more than one year. Binding of 3H-dihydroalprenolol to β-receptors was also evaluated. The isoproterenol-induced rise in cyclic AMP relative to each individual's baseline level was greater in patients on current ketotifen therapy than in other asthmatic patients or non-asthmatic subjects. Ketotifen therapy increased the apparent equilibrium dissociation constant for specific 3H-dihydroalprenolol binding to the receptors. Receptor numbers in symptomatic asthma patients on standard drug therapy were decreased. The results indicate that long term ketotifen therapy is associated with increased responsiveness of β-receptors to stimulation by catecholamines and that this alteration may involve changes in the receptors themselves, their membrane environment, adenylate cyclase or components of the adenylate cyclase coupling system.

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