PT  - JOURNAL ARTICLE
AU  - Y Shimamoto
AU  - H Shimamoto
AU  - C Y Kwan
AU  - E E Daniel
TI  - Rauwolscine induces contraction in the dog mesenteric artery precontracted with KCl and endothelin-1: mediation via 5-hydroxytryptamine1-like receptors.
DP  - 1993 Jan 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 201--209
VI  - 264
IP  - 1
4099  - http://jpet.aspetjournals.org/content/264/1/201.short
4100  - http://jpet.aspetjournals.org/content/264/1/201.full
SO  - J Pharmacol Exp Ther1993 Jan 01; 264
AB  - Rauwolscine, a selective alpha-2 adrenoceptor antagonist, elicited a sustained contraction in the dog mesenteric artery precontracted with 20 mM KCl or 10(-9) M endothelin-1. Cumulative concentration-response curves to rauwolscine were not shifted by spiperone, propranolol, pindolol, mianserin, ketanserin, prazosin or phenoxybenzamine at the concentration of 10(-6) M. The pA2 values against rauwolscine were 8.34 +/- 0.32 for methysergide, 8.52 +/- 0.22 for methiothepin and 5.84 +/- 0.27 for phentolamine, which were in good agreement with the pA2 values for those antagonists against 5-hydroxytryptamine (5-HT) in the dog mesenteric artery precontracted with 20 mM KCl. Contractile responses to 5-HT after pretreatment with 20 mM KCl were antagonized in an apparently competitive manner by 10(-5) M rauwolscine. In the absence of precontraction, rauwolscine also shifted 5-HT-induced contractions in a parallel manner. These data suggest that rauwolscine is a partial agonist with a lower intrinsic activity than 5-HT and acts at the same 5-HT1-like receptors as 5-HT, most probably 5-HT1D receptors, in the dog mesenteric artery precontracted with KCl.