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CORONARY AND PERIPHERAL VASCULAR RESISTANCE IN THE ANAESTHETIZED DIABETIC SHEEP
Author(s) -
Hoffman Linda,
Yong A. C.,
Heath J.,
Kilpatrick D.
Publication year - 1985
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1985.tb00900.x
Subject(s) - methoxamine , medicine , vascular resistance , blood pressure , peripheral , endocrinology , basal (medicine) , diabetes mellitus , cardiology , receptor , agonist
SUMMARY 1. To determine whether vascular resistance was altered in diabetes, the vascular resistance in both the peripheral arterial bed and the circumflex coronary artery was compared in six normal and five diabetic adult sheep, under pentobarbitone anaesthesia. Diabetes induced by alloxan significantly increased blood glucose (15.6mmol/l, s.e.m. = 2.8, vs 5.5 mmol/l, s.e.m. =0.6; P >0.001) compared with controls. 2. Systolic blood pressure was lower in diabetics (92 mmHg, s.e.m. = 12, vs 123 mmHg, s.e.m. =5; P <0.025) as was diastolic blood pressure (73 mmHg, s.e.m. = 15, vs 104 mmHg, s.e.m. =4; P > 0.05). 3. Basal peripheral resistance was lower in diabetics than controls (36.0 mmHg. min/1, s.e.m. = 7.9, vs 42.3 mmHg.min/1, s.e.m. =2.8), but not significantly so. 4. Methoxamine markedly increased peripheral vascular resistance in both groups, but did not change coronary vascular resistance, due to autoregulation. The dose‐response curves of peripheral or coronary arteries to methoxamine showed no significant difference between diabetic and control sheep. Dose‐response curves for isoprenaline and noradrenaline infusion suggested there may be altered β‐receptor sensitivity in diabetes. 5. In conclusion, there are marked differences in the vascular beds of diabetic and normal sheep under basal conditions. In contrast to previous studies, α‐adrenoceptors are not different in diabetics, but further studies in unanaesthetized animals are indicated, as β‐receptor sensitivity may be altered in diabetes.