Distribution of adrenergic receptor subtypes in the retractor muscles of the upper eyelid

Purpose: To identify adrenergic receptor subtypes and their relative distribution in the retractor muscles of the upper eyelid, the levator palpebrae superioris, and the Muller muscle. The pattern of distribution of these receptors in the Muller muscle was further compared in patients with dysthyroid eyelid retraction and in normal subjects. Methods; Muller muscle specimens were collected from 19 patients undergoing ptosis correction and from 8 patients undergoing repair of dysthyroid eyelid retraction. Immunohistochemical staining for α1-, α2-, β1-, and β2-adrenergic receptors was performed using antihuman rabbit polyclonal antibodies. Results: α2-Adrenergic receptors were the predominant subtype in the Muller muscle, and β1-adrenergic receptors were the predominant subtype in the levator muscle. There was no significant difference in the staining pattern between specimens collected from patients with dysthyroid eyelid retraction and those from normal subjects. Conclusions: The interaction between the α2 and β1 receptors in the upper eyelid retractor muscles may be important in the control of the upper eyelid position and may contribute to the development of dysthyroid eyelid retraction. Specific α2 antagonists could be developed and may be effective pharmacologic agents for the treatment of eyelid retraction.