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AIM: To evaluate the effects of beta blockers used in ophthalmology on the release of histamine from mixed cell preparations containing human leukocytes and basophils. METHODS: A mixed leukocyte and basophil preparation was obtained from the venous blood of healthy non-atopic volunteers. Cell preparations were then incubated with betaxolol, metipranolol, timolol, or carteolol. After incubation for one hour, the histamine content of the supernatant was analyzed by automated fluorometric analysis. Cell viability was tested by measuring lactate dehydrogenase (LDH) concentrations. RESULTS: Betaxolol and metipranolol in concentrations of between 10-2 M and 10-3 M liberated histamine from human blood cells in a dose-dependent manner. Carteolol and timolol had no effect on histamine at these concentrations. At the same concentrations, LDH was also detected in the supernatants of cell suspensions incubated with metipranolol or betaxolol. CONCLUSION: Betaxolol and metipranolol induced substantial histamine release from human leukocytes, probably as a result of their cytotoxic effect.
Dr. L.M. van Beek, Department of Ophthalmology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands. l.m.van_beek@lumc.nl
11.3.4 Betablocker (Part of: 11 Medical treatment > 11.3 Adrenergic drugs)