Effects of aging on cerebral vascular responses to serotonin in rats

M. A. Hajdu, R. T. McElmurry, D. D. Heistad, G. L. Baumbach

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24 Scopus citations

Abstract

The purpose of this study was to examine effects of aging on responses of large cerebral arteries to serotonin. We measured cerebral microvascular pressure (with a micropipette and servo-null method), diameter of pial arterioles, and cerebral blood flow (microspheres) in adult (12- to 14-mo- old, n = 15) and aged (24- to 27-mo-old, n = 14) Wistar rats. Responses to intra-atrial infusion of serotonin (5 and 50 μg · kg-1 · min-1) were examined. Infusion of the low dose of serotonin decreased mean arterial pressure and pial arteriolar pressure in adult and aged rats to similar levels. Cerebral blood flow was not reduced in adult or aged rats during infusion of the low dose of serotonin. The high dose of serotonin did not affect mean arterial pressure but reduced pial arteriolar pressure [from 46 ± 4 to 23 ± 2 (SE) in adult rats and from 52 ± 3 to 18 ± 4 mmHg in aged rats]. The high dose of serotonin increased large-artery resistance from 0.9 ± 0.1 to 1.6 ± 0.2 in adult rats and from 0.9 ± 0.1 to 2.7 ± 0.6 mmHg · ml-1 · min · 100 g in aged rats. Cerebral blood flow was reduced significantly in aged rats (from 59 ± 3 to 41 ± 6 ml · min-1 · 100 g- 1), but not in adult rats, during infusion of the high dose of serotonin. We conclude that aging augments constrictor responses of large cerebral arteries to intravascular serotonin, which results in a reduction of cerebral blood flow in aged but not adult rats.

Original languageEnglish (US)
Pages (from-to)H2136-H2140
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume264
Issue number6 33-6
DOIs
StatePublished - 1993

Keywords

  • angiotensin
  • cerebral arteries
  • cerebral arterioles
  • cerebral blood flow

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