Endothelin Receptors in the Cornea, Iris and Ciliary Processes. Evidence from Binding, Secondary Messenger and PCR Studies

N. N. Osborne, N. L. Barnett, W. Luttmann

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)

Abstract

Endothelin (ET)-1 (10 nM) 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 than 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 indirectly involved in the observed responses. However, another type of ET receptor is indicated by the finding that ET-1 reduces 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 no 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.

Original languageEnglish
Pages (from-to)721-728
Number of pages8
JournalExperimental Eye Research
Volume56
Issue number6
DOIs
Publication statusPublished - 1 Jan 1993
Externally publishedYes

Fingerprint

Endothelin Receptors
Endothelin-1
Iris
Cornea
Polymerase Chain Reaction
Endothelin-3
Inositol Phosphates
Endothelin-2
Corneal Endothelium
Colforsin
Indomethacin
Muscles
Phospholipases A2
Endothelins
Epithelium
Binding Sites

Cite this

@article{f70092eebcea493f8fcbb7c4eeb4625a,
title = "Endothelin Receptors in the Cornea, Iris and Ciliary Processes. Evidence from Binding, Secondary Messenger and PCR Studies",
abstract = "Endothelin (ET)-1 (10 nM) 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 than 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 indirectly involved in the observed responses. However, another type of ET receptor is indicated by the finding that ET-1 reduces 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 no 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.",
author = "Osborne, {N. N.} and Barnett, {N. L.} and W. Luttmann",
year = "1993",
month = "1",
day = "1",
doi = "10.1006/exer.1993.1089",
language = "English",
volume = "56",
pages = "721--728",
journal = "Experimental Eye Research",
issn = "0014-4835",
publisher = "Academic Press Inc.",
number = "6",

}

Endothelin Receptors in the Cornea, Iris and Ciliary Processes. Evidence from Binding, Secondary Messenger and PCR Studies. / Osborne, N. N.; Barnett, N. L.; Luttmann, W.

In: Experimental Eye Research, Vol. 56, No. 6, 01.01.1993, p. 721-728.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Endothelin Receptors in the Cornea, Iris and Ciliary Processes. Evidence from Binding, Secondary Messenger and PCR Studies

AU - Osborne, N. N.

AU - Barnett, N. L.

AU - Luttmann, W.

PY - 1993/1/1

Y1 - 1993/1/1

N2 - Endothelin (ET)-1 (10 nM) 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 than 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 indirectly involved in the observed responses. However, another type of ET receptor is indicated by the finding that ET-1 reduces 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 no 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.

AB - Endothelin (ET)-1 (10 nM) 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 than 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 indirectly involved in the observed responses. However, another type of ET receptor is indicated by the finding that ET-1 reduces 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 no 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.

UR - http://www.scopus.com/inward/record.url?scp=0027284790&partnerID=8YFLogxK

U2 - 10.1006/exer.1993.1089

DO - 10.1006/exer.1993.1089

M3 - Article

VL - 56

SP - 721

EP - 728

JO - Experimental Eye Research

JF - Experimental Eye Research

SN - 0014-4835

IS - 6

ER -