Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1996-4-16
pubmed:abstractText
Endothelin (ET)-1 (10 nanoM) is about six times more effective than ET-3 in contracting the isolated iris sphincter muscle; the ET-1-induced contraction is insensitive to indomethacin treatment. The effect of ET-2 is intermediatory between ET-1 and ET-3 in contracting the muscle. The relative potency of the ETs to stimulate inositol phosphates (InsPs) in the iris-ciliary processes is ET-1 > ET-2 > ET-3, with ET-1 about six times more potent then ET-3; these effects are also insensitive to indomethacin. Studies utilizing the polymerase chain reaction (PCR) show that ETB receptors are present. Although no evidence could be found for the occurrence of ETA receptors, their presence cannot be excluded. These results suggest that the stimulation of InsPs and contraction of the iris sphincter muscle by ET is mediated by ETB receptors and that products generated via activation of phospholipase A2 are not directly involved in the observed responses. However, another type of ET receptor is indicated by the finding that ET-1 reduced the forskolin-elevated cAMP levels in the iris-ciliary epithelium. Autoradiographic results show that specific [125I]ET-1 binding sites are associated with the iris, ciliary processes and the corneal endothelium. As in the iris-ciliary process tissues, ET-1 is the most effective of the three ETs stimulating InsPs in the cornea, although statistically the differences were insignificant. Moreover, ET-1 was found to have not effect on the forskolin-elevated cAMP levels in the cornea. Whether these results reflect true differences between the ET receptors in the iris-ciliary processes and corneal endothelium remains to be established.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-4835
pubmed:author
pubmed:issnType
Print
pubmed:volume
56
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
721-8
pubmed:dateRevised
2009-9-29
pubmed:meshHeading
pubmed-meshheading:8595814-Animals, pubmed-meshheading:8595814-Autoradiography, pubmed-meshheading:8595814-Base Sequence, pubmed-meshheading:8595814-Binding Sites, pubmed-meshheading:8595814-Ciliary Body, pubmed-meshheading:8595814-Cornea, pubmed-meshheading:8595814-Cyclic AMP, pubmed-meshheading:8595814-DNA Primers, pubmed-meshheading:8595814-Endothelins, pubmed-meshheading:8595814-Forskolin, pubmed-meshheading:8595814-Inositol Phosphates, pubmed-meshheading:8595814-Iris, pubmed-meshheading:8595814-Molecular Sequence Data, pubmed-meshheading:8595814-Muscle, Smooth, pubmed-meshheading:8595814-Muscle Contraction, pubmed-meshheading:8595814-Polymerase Chain Reaction, pubmed-meshheading:8595814-Rabbits, pubmed-meshheading:8595814-Receptors, Endothelin, pubmed-meshheading:8595814-Second Messenger Systems
pubmed:year
1993
pubmed:articleTitle
Endothelin receptors in the cornea, iris and ciliary processes. Evidence from binding, secondary messenger and PCR studies.
pubmed:affiliation
Nuffield Laboratory of Ophthalmology, Oxford University, U.K.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't