EurekaMag.com logo
+ Translate

Regulation of large coronary vessels by adrenergic mechanisms in conscious dogs


, : Regulation of large coronary vessels by adrenergic mechanisms in conscious dogs. Basic Research in Cardiology 76(5): 508-517

The effects of .alpha.- and .beta.-adrenergic stimulation were examined in conscious dogs on measurements of left circumflex coronary blood flow and coronary arterial diameter and on calculations of mean coronary resistance (MCR) and left circumflex coronary internal cross-sectional area (CSA). Methoxamine (50 .mu.g/kg per min), after transiently increasing left circumflex coronary dimensions, induced sustained reductions in left circumflex coronary diameter (9 .+-. 2%) and CSA (27 .+-. 5%) at a time when mean arterial pressure rose by 65 .+-. 5%, left ventricular (LV) dP/dt [change in pressure over time] had decreased only slightly, and heart rate and mean coronary blood flow were at control levels. Isoproterenol (0.1 .mu.g/kg per min) increased heart rate by 66 .+-. 8%, LV dP/dt by 58 .+-. 5%, and CSA by 17 .+-. 3%, while it decreased mean arterial pressure by 12 .+-. 1% and MCR by 44 .+-. 5%. After .beta.1-adrenergic receptor blockade and with heart rate held constant, isoproterenol did not increase LV dP/dt but decreased mean arterial pressure similarly (13 .+-. 2%) and induced attenuated increases in CSA (6 .+-. 1%), and decreases in MCR (17 .+-. 3%). After combined .beta.1- and .beta.2-adrenergic receptor blockades isoproterenol induced no significant effects. In the conscious dog, large coronary vessels not only react passively to changes in aortic pressure but also undergo substantial active changes. .alpha.-Adrenergic stimulation is sufficiently powerful to reduce CSA, despite the opposing elevation of distending pressure. Large vessels appear to be regulated by .beta.1-adrenergic mediated increase in myocardial metabolic demands and by .beta.2-adrenergic mediated vasodilation.

Accession: 006288964

PMID: 6272684

DOI: 10.1007/bf01908352

Download PDF Full Text: Regulation of large coronary vessels by adrenergic mechanisms in conscious dogs


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Related references

Vatner, S.F.; Knight, D.; Hintze, T.H., 1984: Beta 1-adrenergic regulation of large coronary arteries in conscious dogs. Bibliotheca Cardiologica: 169-177

Vatner S.F.; Macho P., 1980: Regulation of large coronary vessels by augmented myo cardial metabolism in conscious dogs. Blood Vessels 17(3): 167

Vatner, S.F.; Hintze, T.H.; Macho, P., 1982: Regulation of large coronary arteries by beta-adrenergic mechanisms in the conscious dog. We examined, in conscious dogs, the effects of beta-adrenergic stimulation on measurements of left circumflex coronary arterial diameter and blood flow and on calculations of late diastolic coronary resistance (LDCR) and left circumflex coronary i...

Hashimoto K.; Ohbayashi Y.; Bito K.; Kinoshita M., 1988: Effects of beta adrenergic blockades on epicardial coronary artery and coronary resistance vessels in conscious dogs. Japanese Circulation Journal 52(9): 1018

Heloire, Fçois.; Hittinger, L.; Champagne, Séphane.; Suto, Y.; Houel, Rémi.; Ennezat, P-Vladimir.; Sambin, L.; Crozatier, B.; Su, J.Bo., 2002: Different effects of mibefradil and amlodipine on coronary vessels and during beta-adrenergic stimulation in conscious dogs. Coronary effects of Ca2+-channel blockers mibefradil and amlodipine were compared in conscious dogs. Ten dogs were instrumented for measurement of aortic and left ventricular pressures, circumflex coronary blood flow velocity (CBFv), and coronary...

Hintze T.; Macho P.; Vatner S.F., 1980: Effects of nifedipine on large and small coronary vessels in the presence and absence of coronary vaso constriction in conscious dogs. Circulation Supplement 62(3): III-253

Okajima, M.; Parent, R.; Thorin, E., 2004: Pathophysiological plasma ET-1 levels antagonize b-adrenergic dilation of coronary resistance vessels in conscious dogs. American Journal of Physiology 287(4): 476-H1483

Vatner S.F., 1981: Effects of acetyl choline on large coronary vessels in conscious dogs. Federation Proceedingspart 1: 707

Nishijima H.; Tomoike H.; Adachi H.; Egashira S.; Nakamura M., 1987: Effect of 5 hydroxytryptamine 5 ht on large and resistance coronary vessels in conscious dogs. Japanese Circulation Journal 51(7): 713

Zhang J.; Somers M.J.; Cobb F.R., 1992: Differential sensitivity of coronary conductance cv and resistance vessels rv to nitroglycerin ntg is due to different metabolic rather than local coronary hemodynamic or anatomic mechanisms in conscious dogs. FASEB Journal 6(5): A1802