title: Neurotransmitter influence on human meibomian gland epithelial cells.
abstract: OBJECTIVE
  A striking characteristic of the human meibomian gland is its rich sensory, sympathetic, and parasympathetic innervation, yet the functional relevance of these nerve fibers remains unknown. Acting on the hypothesis that neurotransmitters are released in the vicinity of the gland, act on glandular receptors, and influence the production, secretion, and/or delivery of meibomian gland secretions to the ocular surface, the goal in this study was to begin to determine whether neurotransmitters influence the meibomian gland.
  
  
  METHODS
  Immortalized human meibomian gland epithelial (SLHMG) cells were examined for the presence of vasoactive intestinal peptide (VIP) and muscarinic acetylcholine (mACh) receptor transcripts and proteins. Cells were also exposed to VIP, carbachol, forskolin, and/or 3-isobutyl-1-methylxanthine (IBMX) to determine whether these agents, alone or in combination, modulate the adenylyl cyclase pathway, the accumulation of intracellular free calcium ([Ca2+]i), or cell proliferation.
  
  
  RESULTS
  Results demonstrate that SLHMG cells transcribe and translate VIP and mACh receptors; VIP, with either IBMX or forskolin, activates the adenylyl cyclase pathway, and the effect of VIP and forskolin together is synergistic; both VIP and carbachol increase intracellular [Ca2+] in SLHMG cells; and VIP with forskolin stimulates SLHMG cell proliferation.
  
  
  CONCLUSIONS
  This study shows that parasympathetic neurotransmitters and their agonists influence the function of human meibomian gland epithelial cells. It remains to be determined whether this action alters the production, secretion, and/or delivery of meibum to the ocular surface.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Wendy R
authors.initials: WR
authors.lastname: Kam
authors.forename: David A
authors.initials: DA
authors.lastname: Sullivan
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002461:Cell Line, Transformed; D018679:Cholinergic Agonists / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008537:Meibomian Glands / Q000166:cytology* / Q000294:innervation*; D017777:Parasympathetic Fibers, Postganglionic / Q000502:physiology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000235:genetics / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D018679:Cholinergic Agonists; D010726:Phosphodiesterase Inhibitors; D011976:Receptors, Muscarinic; D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D002217:Carbachol; D000262:Adenylyl Cyclases; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine