Comparison of endothelin-1 and noradrenaline stimulated inositol phosphate formation in cultured aortic smooth muscle cells from spontaneously hypertensive and Wistar Kyoto rats.
Total [3H]-inositol phosphate formation was measured in cultured aortic smooth muscle cells from 6 and 14 week spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) normotensive rats. Basal inositol phosphate formation was significantly increased in cells cultured from SHR compared to WKY at both 6 and 14 weeks as was basal phosphatidylinositol formation. This difference in basal values was apparent after 9 h or more incubation with [3H]-myoinositol. Both endothelin-1 and noradrenaline stimulated inositol phosphate formation was unchanged in cultured smooth muscle cells from 6-week SHR compared to WKY. In cultured smooth muscle cells from 14-week SHR a decrease was observed in endothelin-1 stimulated inositol phosphate formation compared to controls. Noradrenaline stimulated inositol phosphate formation was increased in cultured cells from 14 week SHR. Endothelin-1 and noradrenaline stimulated inositol phosphate formation does not appear to be involved in the development (at 6 weeks) of hypertension in this model. However, in established hypertension (14 weeks) cells from SHR have altered total [3H] inositol phosphate formation in response to stimulation with noradrenaline and endothelin-1 although these changes are in opposite directions. Therefore, in cultured smooth muscle cells from 14-week rats noradrenaline and endothelin-1 appear to be regulated independently with regard to their effects on the phosphatidylinositol cycle.
Nixon
G F
GF
University Department of Medicine and Therapeutics, Gardiner Institute, Western Infirmary, Glasgow, UK.
Hamilton
C A
CA
Wadsworth
R M
RM
Reid
J L
JL
D000367:Age Factors; D000818:Animals; D002478:Cells, Cultured; D016232:Endothelins / Q000494:pharmacology*; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D007295:Inositol Phosphates / Q000096:biosynthesis*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D016232:Endothelins; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D009638:Norepinephrine