RESUMO
The study included two parts, an in vitro part and in vivo one. In the in vitro part, isolated mast cells were preincubated with various concentrations of the drugs for 10 minutes before challenges with the releasers. When ova albumin was used the releaser, mast cells obtained from previously sensitized animals were used. In the in vivo part of the study, the animals were treated with the drugs for one week, after which the mast cells were collected and challenged with the releasers outside the body. The percentage histamine release was determined. In both, in vitro and in vivo, parts of the study no effect of either drug was seen on spontaneous histamine release, while a dose dependent statistically significant potentiation of histamine release induced by either compound 48/80 or ova albumin was seen with pinacidil and an inhibitory effect was noticed with glibenclamide. From these data the decision of the use of pinacidil in bronchial asthma can not be taken except after assessment of its effect on human mast cells particularly that of pulmonary origin. At the same time, a role of potassium channels in the mast cell secretory process is suggested