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Rat thoracic vena cava ETB receptors re‐sensitize faster than venous ETA receptors
Author(s) -
Thakali Keshari,
Gariepy Cheryl E.,
Galligan James J.,
Fink Gregory D.,
Watts Stephanie W.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.965.11
Subject(s) - contraction (grammar) , inferior vena cava , receptor , agonist , medicine , endocrinology , aorta , chemistry , anesthesia
We previously demonstrated that aorta completely and vena cava partially desensitize to ET‐1. We hypothesized that vena cava from male ET B receptor deficient rats (sl) would completely desensitize to ET‐1, like aorta from male wild‐type (WT) rats because they both lack functional ET B receptors. Initial maximal contraction to ET‐1 (100 nM) was not different between vena cava from sl and WT rats [sl: 409±65% norepinephrine (10 μM) contraction; WT: 499±68%]. After washing out the first ET‐1 challenge, the second maximal contraction to ET‐1 (100 nM) was similarly reduced compared to the first between vena cava from sl and WT rats (sl: 99±37%; WT: 97±7%). Vena cava from male Sprague Dawley rats were contracted with the ET B receptor agonist sarafotoxin 6c (S6c, 100 nM, 15 minutes), the S6c was washed out for 15 and 30 minutes, and then challenged again with S6c (100 nM). After 15 minutes of washing, vena cava did not contract to the second S6c challenge. After 30 minutes of washing, the contraction to the second S6c challenge was the same as the initial S6c‐induced contraction [initial: 145±20% norepinephrine (10 μM) contraction; 30 min: 139±38%]. Our data demonstrate that the venous ET B receptor does desensitize, and is not involved in remaining venous ET‐1‐induced contraction after desensitization. Our data also suggest that the mechanism of ET receptor desensitization differs between arteries and veins.