{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T12:31:23Z","timestamp":1779366683674,"version":"3.53.0"},"reference-count":0,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"4","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[1992,10]]},"abstract":"<jats:sec>\n            <jats:title>BACKGROUND<\/jats:title>\n            <jats:p>Experimental studies on the effects of alpha 2-adrenoceptors on regional coronary blood flow in normal and ischemic myocardium are highly controversial. A beneficial effect on regional ischemic myocardium has been demonstrated in different animal preparations with either alpha 2-adrenoceptor blockade or stimulation. Animal studies also demonstrated that postsynaptic alpha 2-adrenoceptors mediate vasoconstriction in coronary and femoral vascular beds. The aims of the study were 1) to investigate the effects of regional alpha 2-adrenoceptor stimulation on regional coronary blood flow in subjects with angiographically normal coronary arteries, 2) to assess the effect of alpha 2-adrenoceptor blockade on coronary circulation in control subjects, and 3) to examine the influence of atherosclerosis on coronary blood flow response to alpha 2-adrenoceptor blockade.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>METHODS AND RESULTS<\/jats:title>\n            <jats:p>The effect of regional administration of BHT 933 (a selective alpha 2-adrenoceptor agonist) was studied in eight subjects with angiographically normal coronary arteries. The coronary blood flow velocity was measured using a subselective intracoronary 3F Doppler catheter and coronary diameter by quantitative coronary angiography. BHT 933 induced a reduction in coronary artery diameter from 2.5 +\/- 0.6 mm to 1.8 +\/- 0.4 mm (p less than 0.05) as well as in coronary blood flow velocity (from 6.4 +\/- 0.9 cm\/sec to 4.6 +\/- 1.9 cm\/sec, p less than 0.01). In some subjects, ST segment abnormalities occurred. In patients with angiographically normal coronary arteries (n = 6), the regional infusion of a selective alpha 2-adrenoceptor blocking agent after beta-blockade did not change coronary diameter or coronary blood flow velocity. In contrast, in patients with significant coronary stenoses (n = 6), regional infusion of an alpha 2-adrenoceptor blocking agent reduced regional coronary artery diameter (from 2.3 +\/- 0.5 mm to 2.1 +\/- 0.6 mm, p less than 0.01) as well as coronary blood flow velocity (from 5.8 +\/- 0.8 cm\/sec to 3.7 +\/- 0.6 cm\/sec, p less than 0.05); in addition, alpha 2-adrenoceptor blockade significantly increased coronary sinus plasma norepinephrine levels (from 300 +\/- 144 pg\/ml to 429 +\/- 207 pg\/ml, p less than 0.01).<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>CONCLUSIONS<\/jats:title>\n            <jats:p>The selective in vivo stimulation of alpha 2-adrenoceptors produces a reduction in coronary blood flow and diameter in humans with angiographically normal coronary arteries. alpha 2-Adrenergic blockade does not change coronary blood flow in subjects with angiographically normal coronary arteries (suggesting no resting alpha 2-adrenergic vasoconstrictor tone), whereas in patients with coronary artery stenosis, regional coronary blood flow decreases after alpha 2-receptor blockade. Finally, our data also suggest that alpha 2-adrenoceptors participate in the modulation of sympathetic neuronal norepinephrine release in the human heart.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1161\/01.cir.86.4.1116","type":"journal-article","created":{"date-parts":[[2012,6,12]],"date-time":"2012-06-12T00:01:09Z","timestamp":1339459269000},"page":"1116-1124","update-policy":"https:\/\/doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":45,"title":["Role of alpha 2-adrenoceptors in normal and atherosclerotic human coronary circulation."],"prefix":"10.1161","volume":"86","author":[{"given":"C","family":"Indolfi","sequence":"first","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F","family":"Piscione","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"B","family":"Villari","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"E","family":"Russolillo","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V","family":"Rendina","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P","family":"Golino","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M","family":"Condorelli","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M","family":"Chiariello","sequence":"additional","affiliation":[{"name":"Department of Medicine, University Federico II, Napoli, Italy."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","container-title":["Circulation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ahajournals.org\/doi\/pdf\/10.1161\/01.CIR.86.4.1116","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,12]],"date-time":"2024-05-12T15:41:32Z","timestamp":1715528492000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/01.CIR.86.4.1116"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1992,10]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1992,10]]}},"alternative-id":["10.1161\/01.CIR.86.4.1116"],"URL":"https:\/\/doi.org\/10.1161\/01.cir.86.4.1116","relation":{},"ISSN":["0009-7322","1524-4539"],"issn-type":[{"value":"0009-7322","type":"print"},{"value":"1524-4539","type":"electronic"}],"subject":[],"published":{"date-parts":[[1992,10]]},"assertion":[{"value":"1992-10-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}