Editing Gap junction (section)

===Hemichannel function===
{{Multiple image
| image1            = Epithelium Cx50.jpg
| caption1          = Lens epithelial cells with gap junctions and hemichannels at the interface with fiber cells.
| image2            = Fiber ends Cx50-1.jpg
| caption2          = Lens fiber cells ends with gap junctions and hemichannels at the interface with fiber cells.
}}
Hemichannels contribute to a cellular network of gap junctions and allow the release of [[sdenosine triphosphate]], [[glutamate]], [[Nicotinamide adenine dinucleotide]], and [[prostaglandin E2]] from cells, which can all act as messengers to cells otherwise disconnected from such messaging.<ref>{{cite journal |last1=Evans |first1=W. Howard |last2=De Vuyst |first2=Elke |last3=Leybaert |first3=Luc |title=The gap junction cellular internet: connexin hemichannels enter the signalling limelight |journal=Biochemical Journal |date=1 July 2006 |volume=397 |issue=1 |pages=1–14 |doi=10.1042/BJ20060175|pmid=16761954 |pmc=1479757 }}</ref> In this sense, a gap junction plaque forms a one-to-one relationship with the neighboring cell, daisy chaining many cells together. Hemichannels form a one to many relationship with the surrounding tissue.

On a larger scale, the one-to-many communication of cells is typically carried out by the vascular and nervous systems. This makes detecting the contribution of hemichannels to extracellular communication more difficult in whole organisms. With the eye lens, the vascular and nervous systems are absent, making reliance on hemichannels greater and their detection easier. At the interface of the lens with the aqueous humor (where the lens exchanges metabolites), both gap junction plaques and more diffused connexon distribution can be seen in the accompanying micrographs.