title: Identification of GABA receptors in chick cornea.
abstract: OBJECTIVE
  The cornea has an important role in vision, is highly innervated and many neurotransmitter receptors are present, e.g., muscarine, melatonin, and dopamine receptors. γ-aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the retina and central nervous system, but it is unknown whether GABA receptors are present in cornea. The aim of this study was to determine if GABA receptors are located in chick cornea.
  
  
  METHODS
  Corneal tissues were collected from 25, 12-day-old chicks. Real time PCR, western blot, and immunohistochemistry were used to determine whether alpha(1) GABA(A), GABA(B), and rho(1) GABA(C) receptors were expressed and located in chick cornea.
  
  
  RESULTS
  Corneal tissue was positive for alpha(1) GABA(A) and rho(1) GABA(C) receptor mRNA (PCR) and protein (western blot) expression but was negative for GABA(B) receptor mRNA and protein. Alpha(1) GABA(A) and rho(1) GABA(C) receptor protein labeling was observed in the corneal epithelium using immunohistochemistry.
  
  
  CONCLUSIONS
  These investigations clearly show that chick cornea possesses alpha(1) GABA(A), and rho(1) GABA(C) receptors, but not GABA(B) receptors. The purpose of the alpha(1) GABA(A) and rho(1) GABA(C) receptors in cornea is a fascinating unexplored question.
authors.affiliation: Myopia Center, Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, Shandong, China.
authors.forename: Zhen-Ying
authors.initials: ZY
authors.lastname: Cheng
authors.forename: Mary
authors.initials: M
authors.lastname: Chebib
authors.forename: Katrina L
authors.initials: KL
authors.lastname: Schmid
mesh_terms: D000818:Animals; D002645:Chickens; D003315:Cornea / Q000378:metabolism*; D015870:Gene Expression; D007150:Immunohistochemistry; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D018079:Receptors, GABA / Q000235:genetics* / Q000378:metabolism; D011963:Receptors, GABA-A / Q000235:genetics* / Q000378:metabolism; D018080:Receptors, GABA-B / Q000235:genetics / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: C087200:GABA-C receptor; D021122:Protein Subunits; D012333:RNA, Messenger; D018079:Receptors, GABA; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D005680:gamma-Aminobutyric Acid