The Alpha ( )-Glucosidase Inhibitor, Acarbose, Attenuates the Blood Pressure and Splanchnic Blood Flow Responses to Intraduodenal Sucrose in Older Adults

Abstract

Postprandial hypotension is an important problem in the elderly and may be triggered by the increase in splanchnic blood flow induced by a meal. Acarbose attenuates the fall in blood pressure (BP) induced by oral sucrose and may be useful in the management of postprandial hypotension. It is not known whether the effect of acarbose on postprandial BP reflects slowing of gastric emptying and/or carbohydrate absorption nor whether acarbose affects splanchnic blood flow. We examined the effects of intraduodenal (ID) acarbose on the BP, heart rate, superior mesenteric artery (SMA) flow, and glycemic and insulin responses to ID sucrose in older participants--this approach excluded any "gastric" effect of acarbose. Eight healthy participants (four male and four female, age 66-77 years) received an ID infusion of sucrose (~6 kcal/min), with or without acarbose (100 mg), over 60 minutes. BP, heart rate, SMA flow, blood glucose, and serum insulin were measured. Acarbose markedly attenuated the falls in systolic (p < .01) and diastolic (p < .05) BP and rises in heart rate (p < .05), SMA flow (p < .05), blood glucose (p < .01), and serum insulin (p < .05). The maximum fall in systolic BP and peak SMA flow was inversely related on the control day (r(2) = -.53, p < .05) but not with acarbose (r(2) = .03, p = .70). We conclude that in healthy older participants receiving ID sucrose, (a) acarbose markedly attenuates the hypotensive response by slowing carbohydrate absorption and attenuating the rise in splanchnic blood flow and (b) the fall in BP is related to the concomitant increase in SMA flow.