Alpha2-adrenergic receptors are present in normal human conjunctiva.
OBJECTIVE
Despite the passage of medications, including antiglaucoma drugs, through the ocular surface, and despite the increasing relevance of neurogenic inflammation in the ocular surface, the presence of some neuroreceptors in the conjunctiva has not been ascertained. This study describes the presence of alpha2-adrenergic receptors in normal human conjunctiva.


METHODS
Immunofluorescence microscopy, electrophoresis, and Western blot analyses were done in human conjunctival biopsies and rat control tissues. Antibodies against alpha2-adrenergic receptor subtypes alpha2A, alpha2B, and alpha2C were used.


RESULTS
Immunoreactivity for alpha2A- and alpha2B-, but not alpha2C-adrenergic receptors was evenly distributed in epithelial cells of human conjunctiva cryosections. Immunoreactive bands were detected for the three alpha2-adrenergic receptor subtypes: a major band of 48-50 kDa and fellow bands of 65-67 kDa.


CONCLUSIONS
Normal human conjunctival epithelial cells express alpha2A-, alpha2B-, and alpha2C-adrenergic receptors. Further studies to determine the functional implications of these receptors in ocular surface homeostasis are warranted.
Diebold
Yolanda
Y
IOBA, University of Valladolid, Valladolid, Spain. yol@ioba.med.uva.es
Enríquez de Salamanca
Amalia
A
Calonge
Margarita
M
Sáez
Victoria
V
Callejo
Sagrario
S
Stern
Michael E
ME
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015153:Blotting, Western; D003228:Conjunctiva / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D051381:Rats; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*
D018341:Receptors, Adrenergic, alpha-2