Article date: May 1993
By: N. Miasiro, C.R. Nakaie, A.C.M. Paiva, in Volume 109, Issue 1, pages 68-72
In the guinea‐pig ileum the C‐terminal hexapeptide of the endothelins, endothelin (16–21), induced a biphasic effect (relaxation followed by contraction) qualitatively similar to that seen in the responses to endothelins 1 and 3. Both components of the response were concentration‐dependent in the range studied (2–100 μm).
The response induced by endothelin (16–21) was inhibited in low‐sodium (80 mm) medium.
Repeated administration of endothelin (16–21) induced no desensitization of the preparation, contrasting with the tachyphylaxis induced by endothelin‐1 and endothelin‐3 in the guinea‐pig ileum.
Tissues rendered tachyphylatic to endothelin‐1 or endothelin‐3 responded normally to endothelin (16–21).
The results suggest that the C‐terminal tail of the endothelins contains the message for the biphasic response, whereas the N‐terminal domain may be responsible for the strong binding to the receptor and for the tachyphylactic properties of endothelin‐1 and endothelin‐3, in the guinea‐pig isolated ileum. However, the possibility that endothelin (16–21) may be acting on a site other than the endothelin receptor cannot be ruled out.
In the guinea‐pig ileum the C‐terminal hexapeptide of the endothelins, endothelin (16–21), induced a biphasic effect (relaxation followed by contraction) qualitatively similar to that seen in the responses to endothelins 1 and 3. Both components of the response were concentration‐dependent in the range studied (2–100 μm).
The response induced by endothelin (16–21) was inhibited in low‐sodium (80 mm) medium.
Repeated administration of endothelin (16–21) induced no desensitization of the preparation, contrasting with the tachyphylaxis induced by endothelin‐1 and endothelin‐3 in the guinea‐pig ileum.
Tissues rendered tachyphylatic to endothelin‐1 or endothelin‐3 responded normally to endothelin (16–21).
The results suggest that the C‐terminal tail of the endothelins contains the message for the biphasic response, whereas the N‐terminal domain may be responsible for the strong binding to the receptor and for the tachyphylactic properties of endothelin‐1 and endothelin‐3, in the guinea‐pig isolated ileum. However, the possibility that endothelin (16–21) may be acting on a site other than the endothelin receptor cannot be ruled out.
DOI: 10.1111/j.1476-5381.1993.tb13532.x
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