Topical anti-inflammatory activity of beta 2-adrenoceptor agonists in the conjunctiva

Increased microvascular permeability is believed to involve the contraction of venular endothelial cells, which results in the formation of leaking gaps in the postcapillary segment of the microvasculature. Several reports have suggested that interendothelial cell gap formation caused by permeability factors may be functionally antagonized by locally administered beta 2-adrenoceptor agonists. This represents a potentially novel approach for reducing inflammatory episodes in a variety of externally accessible tissues. The studies described herein extend these findings to the conjunctiva, where the relatively selective beta 2-adrenoceptor agonists salbutamol and terbutaline reduced the microvascular permeability response to histamine. Similarly, pretreatment with salbutamol or terbutaline inhibited the increase in conjunctival microvascular permeability associated with experimental immediate hypersensitivity, which indicates potential utility for allergic conjunctivitis.