ISSN:
1432-5233
Keywords:
Key words Insulin
;
β-adrenergic
;
Blood pressure
;
Blood flow
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Insulin administration results in vasodilation, decreased mean arterial blood pressure (MAP) and increased conductances (flow/MAP) in various vascular beds. β-adrenergic blockers antagonize this response, but the mechanism of the interplay between insulin-induced vasodilation and β-adrenergic antagonism is unknown. In this study, we evaluated the effects of β-blockade using the selective β2 antagonist ICI 118551 or the general β-antagonist propranolol on insulin-induced cardiac and regional flow responses in normal rats. Insulin-induced responses were also examined following adrenalectomy. Rats were anaesthetized and the femoral vein and artery were cannulated for infusions, sampling or monitoring of MAP and heart rate (HR). The iliac, renal, and superior mesentery arteries were equipped with pulsed-Doppler flow probes. Blood samples were collected at selected intervals. Insulin decreased blood glucose, MAP and increased conductances. Pretreatment with propranolol not only antagonized the insulin-induced decrease in MAP and increased conductance but insulin also then increased MAP and decreased conductances. ICI 11851, like propranolol, antagonized the insulin-induced decrease in MAP and increased iliac and renal artery conductances. Adrenalectomy did not alter the maximum insulin-induced effects on MAP and conductances but prevented the rebound recovery phase. β-blockade following adrenalectomy had the same effects as β-blockade alone on the insulin-induced responses. We conclude that the insulin-induced decrease in MAP and the increased flow in the selective vascular beds are modulated by a sympathetic β2-receptor-mediated pathway and this response is not due primarily to the release of adrenal catecholamine.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s005920050145
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