Topical ophthalmic β blockers may cause release of histamine through cytotoxic effects on inflammatory cells
- aDepartment of Ophthalmology, Leiden University Medical Centre, Netherlands, bNetherlands Ophthalmic Research Institute, Netherlands, cDepartment of Allergy, CLB and Laboratory for Experimental and Clinical Immunology, Academic Medical Centre, University of Amsterdam, Netherlands, dDepartment of Ophthalmology, eInstitute for Animal Science and Health, Lelystad, Netherlands
- Dr L M van Beek, Department of Ophthalmology, Leiden University Medical Centre, P O Box 9600, 2300 RC Leiden, Netherlands l.m.van_beek{at}lumc.nl
- Accepted 26 April 2000
Abstract
AIM To evaluate the effects of β blockers used in ophthalmology on the release of histamine from mixed cell preparations containing human leucocytes and basophils.
METHODS A mixed leucocyte and basophil preparation was obtained from venous blood of healthy non-atopic volunteers. Cell preparations were then incubated with betaxolol, metipranolol, timolol, or carteolol. After incubation for 1 hour the histamine content of the supernatant was analysed by automated fluorometric analysis. Cell viability was tested by measuring lactate dehydrogenase (LDH) concentrations.
RESULTS Betaxolol and metipranolol in concentrations 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.
CONCLUSIONS Betaxolol and metipranolol induce substantial histamine release from human leucocytes, probably as a result of their cytotoxic effect.
